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Brown, Richard. "Microbrachytherapy treatment planning." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30180/document.
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Une nouvelle modalité de radiothérapie, la micro-curiethérapie, est en cours de développement. Cette thérapie cible des tumeurs solides inopérables en effectuant des injections de liquide contenant des microsphères radioactives en suspension. Plusieurs injections sont nécessaires pour suffisamment irradier la zone tumorale et donc, afin d'optimiser le positionnement de ces injections, une méthode de planification de traitement nécessaire a été développée et validée au cours de cette thèse. Tout au long de ce travail, trois thèmes principaux seront discutés : • Comment réaliser la dosimétrie particulière de cette micro-curiethérapie ? • Comment effectuer la planification de traitement pour cette modalité ? • Comment optimiser le plan de traitement afin qu'il soit le plus efficace possible ? La dosimétrie en micro-curiethérapie a été réalisée en calculant la distribution de dose absorbée pour une injection. Cette distribution a été convoluée à la position des autres injections dans la tumeur pour calculer la distribution de dose absorbée dans le patient. Pour effectuer la dosimétrie spécifique dans la tumeur et les organes à risque, les histogrammes dose-volume (HDV) ont été extraits et analysés. Une fois la méthode de dosimétrie établie, nous avons développé une méthodologie de planification de traitement pour développer et optimiser le plan pour chaque patient. Pour cela, nous avons testé et comparé trois algorithmes : la méthode de Nelder-Mead, l'algorithme des abeilles et l'algorithme "Non-Dominated Sorting Genetic Algorithm II" (NSGA II). Nous avons montré que, grâce à l'optimisation multiobjectif, le NSGA II donne plus de liberté à l'utilisateur ; c'est pourquoi il a été utilisé par la suite. Enfin, nous avons effectué une comparaison entre les paramètres d'injection. Nous avons mis en évidence qu'entre les radio-isotopes 90Y, 166Ho, 131I and 177Lu, les injections de 90Y sont optimales. Nous avons testé des injections de 5, 10 et 20 µL et des activités initiales de 5, 10 et 20 MBq. Nous avons trouvé que des injections de 20 µL avec 20 MBq sont optimales car celles-ci permettent de minimiser le nombre d'injections requis. Cette nouvelle technologie associée aux développements réalisés dans ses travaux démontre la faisabilité, qui a pu être validée sur animal, de pouvoir injecter un liquide contenant des microsphères radioactives en suspension afin de pouvoir traiter efficacement, tout en préservant les tissus sains environnants, des tumeurs inopérables encore de mauvais pronostic aujourd'hui, mais surement mieux prises en charge dans un proche avenirAn innovative form of radiotherapy, microbrachytherapy, is under development. This therapy targets solid, inoperable tumours by performing injections of liquid containing radioactive microspheres in suspension. Many injections are required to sufficiently cover the tumoural volume, and so to be able to deliver the position of these injections, a method of treatment planning has been developed and validated throughout this research. Throughout this work, three main questions are addressed: • How to perform the dosimetry for microbrachytherapy? • How to perform treatment planning for this modality? • What are the optimal injection properties to deliver the most efficient treatment? Microbrachytherapy dosimetry was performed by calculating the absorbed dose distribution for an injection. This distribution was then convolved at each injection position within the tumour to calculate the patient's absorbed dose distribution. Dosimetry of the tumour and the organs at risk was performed by extracting and analysing dose-volume histograms (DVHs). Once a method of dosimetry was put in place, optimisation algorithms were developed to generate patient-specific treatment plans. For this, three algorithms were tested and compared: Nelder-Mead Simplex, the Bees algorithm and the non-dominated sorting genetic algorithm II. It was found that, thanks to its MO optimisation, the non-dominated sorting algorithm II was the most flexible, and was used preferentially. Lastly, a comparison of injection parameters was performed. It was found that between 90Y, 166Ho, 131I and 177Lu, optimal injections consisted of microspheres of 90Y. Injection volumes of 5, 10 and 20 µL and initial activities of 5, 10 and 20 MBq were tested. It was found that 20 µL injections with 20 MBq were optimal because they minimise the number of injections required. This new technology combined with developments shown in this work demonstrate the feasibility - that was validated on animals - the ability to inject liquid containing radioactive microspheres in suspension to efficiently treat inoperable tumours whilst protecting surrounding healthy tissue. Such tumours, despite still having a poor prognosis, will surely have better support in the near future
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Neufeld, Esra. "High resolution hyperthermia treatment planning." Konstanz Hartung-Gorre, 2008. http://d-nb.info/992327873/04.
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Qasrawi, Radwan. "Treatment planning methods for clinical electroporation." Doctoral thesis, Universitat Pompeu Fabra, 2017. http://hdl.handle.net/10803/441753.
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Two treatment modalities based on the electroporation phenomenon, electro-chemotherapy and irreversible electroporation, have been developed in the last decades to destroy solid tumors. These treatments are based on the delivery of short high voltage pulses across electrodes and their success depends on covering the whole tumor with an adequate electric field magnitude. This leads to a need for software tools capable of allowing patient-specific treatment planning. In particular, there is a need for treatment planning tools similar to those used in radiotherapy in order to plan the location of the electrodes and the voltage magnitudes to be applied across these electrodes.
Here it is described a treatment planning platform prototype which allows users to perform the complete treatment planning sequence in a single environment. The planned treatment volume is represented on the patient medical images after computing, by the finite element method, the electric field magnitude generated by needle-shaped electrodes.
Here it is also reported a study in which the above prototype was employed for analyzing the potential impact of liver blood vessels on tumor ablation by irreversible electroporation. From this study it is concluded that those vessels must not be neglected in treatment planning and that undertreatment around those vessels may be occurring frequently in current irreversible electroporation treatments of liver tumors.
Finally, it is described the implementation and characterization of a fast semi-analytical algorithm for computing the electric field distribution generated by needle-shaped electrodes. This algorithm is intended to rapidly pre-visualize the expected treatment region before proceeding with an accurate, but laborious and slow, computation based numerical methods.Dos modalidades de tratamiento basadas en el fenómeno de la electroporación, la electroquimioterapia y la electroporación irreversible, han sido desarrolladas en las últimas décadas para destruir tumores sólidos. Estos tratamientos se basan en la aplicación de pulsos cortos de alta tensión a través de electrodos y para su éxito se requiere abarcar todo el tumor con una magnitud de campo eléctrico adecuada. Esto lleva a la necesidad de herramientas software que permitan la planificación de tratamiento específica del paciente. En particular, existe la necesidad de herramientas de planificación de tratamiento similares a las utilizadas en radioterapia para planificar la ubicación de los electrodos y las magnitudes de voltaje a aplicar a través de estos electrodos. Aquí se describe un prototipo de plataforma de planificación de tratamiento que permite a los usuarios realizar la secuencia completa de planificación de tratamiento en un solo entorno. El volumen planificado de tratamiento se representa sobre las imágenes médicas del paciente después de calcular, mediante el método de elementos finitos, la magnitud del campo eléctrico generada por electrodos en forma de aguja. Aquí también se detalla un estudio en el que el prototipo anterior se empleó para analizar el impacto potencial de los vasos sanguíneos hepáticos sobre la ablación de tumores por electroporación irreversible. De este estudio se concluye que estos vasos no deben ser descuidados en la planificación del tratamiento y que alrededor de esos vasos se puede estar produciendo sub-tratamiento frecuentemente en los tratamientos de electroporación irreversible que actualmente se aplican para tumores hepáticos. Finalmente, se describe la implementación y caracterización de un algoritmo semi-analítico rápido para calcular la distribución de campo eléctrico generada por electrodos en forma de aguja. Este algoritmo está destinado a pre-visualizar rápidamente la región de tratamiento esperada antes de proceder con un preciso, pero laborioso y lento, proceso de cálculo basado en métodos numéricos.
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Perera, Bel Enric. "Treatment planning in electroporation-based therapies." Doctoral thesis, Universitat Pompeu Fabra, 2021. http://hdl.handle.net/10803/673102.
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Diverses teràpies mèdiques es basen en l’electroporació. Entre d’altres, l’electroporació s'usa per al tractament de tumors sòlids. Com que només afecta les cèl·lules i la matriu extracel·lular queda intacta, amb l’electroporació es poden tractar tumors propers a teixits vitals. Tot i aquest clar avantatge respecte d’altres teràpies físiques, els tractaments s’han de planificar amb precisió perquè el resultat és altament dependent dels paràmetres del procediment i de les propietats dels teixits.
Aquesta tesi se centra en el desenvolupament d’eines i models per a la planificació de tractaments amb teràpies basades en electroporació, concretament, per al tractament de tumors interns. A continuació, es relacionen les aportacions d’aquesta tesi. Primer, es descriu el desenvolupament d’una plataforma web que il·lustra la forta dependència de l’electroporació dels paràmetres del tractament i de les propietats elèctriques del teixit, en particular, la dependència del nombre i posició dels elèctrodes, el voltatge aplicat entre parells d’elèctrodes i la conductivitat elèctrica del teixit. Segon, s’estudien models que descriuen la mort cel·lular per predir el volum electroporat en casos de superposició de tractaments amb múltiples parells d’elèctrodes, cosa freqüent en les teràpies basades en electroporació. Per a aquest estudi, es van superposar tractaments per caracteritzar els models de mort cel·lular i, després, aquests models es van usar per analitzar fins a quint punt el volum del tractament es veu afectat en teràpies basades en electroporació. Tercer, es presenta una plataforma per a la planificació de tractaments amb teràpies basades en electroporació. La inserció òptima dels elèctrodes pot ser planificada preoperativament simulant el volum del tractament en models precisos específics per a cada pacient de forma senzilla i ràpida.Tissue electroporation is the basis of several therapies. Among others, it is used in treatments of solid tumors. Because electroporation exclusively targets cells and leaves the extracellular matrix unaffected, tumor treatment near vital structures is feasible, which is a clear advantage over other therapies based on physical methods. However, careful treatment planning is required because electroporation is highly dependent on procedure parameters and tissue properties. This thesis focuses on the development of tools and models for treatment planning in electroporation-based therapies, specifically, for the treatment of internal tumors. The contributions of this thesis are as follows. First, the development of a web platform which illustrates the strong dependence of electroporation on treatment parameters and tissue electrical properties is described. Namely, the dependence on electrode number and positioning, voltage applied between electrode pairs, and tissue electrical conductivity. Second, models which describe cell are presented to predict treatment outcome in cases of treatment overlap with multiple electrode pairs, which are frequent in electroporation-based therapies. This study was performed by first characterizing the cell death models with overlapping treatments, and then, using these models to analyze how the treatment volume was affected in electroporation-based therapies. Third, a platform for treatment planning in electroporation-based therapies is presented. The optimal electrode insertion path can be planned preoperatively by simulating the predicted treatment volume on accurate patient-specific models in an easy-to-use and fast way.
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Huang, Jian. "Visibility problems occurring in radiation treatment planning." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ61012.pdf.
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Moerland, Marinus Adriaan. "Magnetic resonance imaging in radiotherapy treatment planning." [S.l.] : Utrecht : [s.n.] ; Universiteitsbibliotheek Utrecht [Host], 1996. http://www.library.uu.nl/digiarchief/dip/diss/01760825/inhoud.htm.
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Kok, Henny Petra. "Treatment planning for locoregional and intraluminal hyperthermia." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2007. http://dare.uva.nl/document/46767.
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Goorley, John Timothy 1974. "Boron neutron capture therapy treatment planning improvements." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/49670.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1998.Includes bibliographical references.
The Boron Neutron Capture Therapy (BNCT) treatment planning process of the Harvard/MIT team used for their clinical Phase I trials is very time consuming. If BNCT proves to be a successful treatment, this process must be made more efficient. Since the Monte Carlo treatment planning calculations were the most time consuming aspect of the treatment planning process, requiring more than thirty six hours for scoping calculations of three to five beams and final calculations for two beams, it was targeted for improvement. Three approaches were used to reduce the calculation times. A statistical uncertainty analysis was performed on doses rates and showed that a fewer number of particles could not be used and still meet uncertainty requirements in the region of interest. Unused features were removed and assumptions specific to the Harvard/MIT BNCT treatment planning calculations were hard wired into MCNP by Los Alamos personnel, resulting in a thirty percent decrease in runtimes. MCNP was also installed in parallel on the treatment planning computers, allowing a factor of improvement by roughly the number of computers linked together in parallel. After theses enhancements were made, the final executable, MCNPBNCT, was tested by comparing its calculated dose rates against the previously used executable, MCNPNEHD. Since the dose rates in close agreement, MCNPBNCT was adopted. The final runtime improvement to a single beam scoping run by linking the two 200MHz Pentium Pro computers was to reduce the wall clock runtime from 2 hours thirty minutes to fifty nine minutes. It is anticipated that the addition of ten 900 MHz CPUs will further reduce this calculation to three minutes, giving the medical physicist or radiation oncologist the freedom to use an iterative approach to try different radiation beam orientations to optimize treatment. Additional aspects of the treatment planning process were improved. The previously unrecognized phenomenon of peak dose movement during irradiation and its potential for overdosing the subject was identified. A method of predicting its occurrence was developed to prevent this from occurring. The calculated dose rate was also used to create dose volume histograms and volume averaged doses. These data suggest an alternative method for categorizing the subjects, rather than by peak tissue dose.
by John Timothy Goorley.
S.M.
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McGowan, Stacey Elizabeth. "Incorporating range uncertainty into proton therapy treatment planning." Thesis, University of Cambridge, 2015. https://www.repository.cam.ac.uk/handle/1810/248787.
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This dissertation addresses the issue of robustness in proton therapy treatment planning for cancer treatment. Proton therapy is considered to be advantageous in treating most childhood cancers and certain adult cancers, including those of the skull base, spine and head and neck. Protons, unlike X-rays, have a finite range highly dependent on the electron density of the material they are traversing, resulting in a steep dose gradient at the distal edge of the Bragg peak. These characteristics, together with advancements in computation and technology have led to the ability to plan and deliver treatments with greater conformality, sparing normal tissue and organs at risk. Radiotherapy treatment plans aim to meet set dosimetric constraints, and meet them at every fraction. Plan robustness is a measure of deviation between the delivered dose distribution and the planned dose distribution. Due to the same characteristics that make protons advantageous, conventional means of using margins to create a Planning Target Volume (PTV) to ensure plan robustness are inadequate. Additional to this, without a PTV, a new method of analysing plan quality is required in proton therapy. My original contribution to the knowledge in this area is the demonstration of how site- and centre- specific robustness constraints can be established. Robustness constraints can be used both for proton plan analysis and to identify patients that require plans of greater individualisation. I have also used the daily volumetric imaging from patients previously treated with conventional radiotherapy to quantify range uncertainty from inter- and intra-fraction motion. These new methods of both quantifying and analysing the change in proton range in the patient can aid in the choice of beam directions, provide input into a multi- criteria optimisation algorithm or can be used as criteria to determine when adaptive planning may be required. This greater understanding in range uncertainty better informs the planner on how best to balance the trade-off between plan conformality and robustness in proton therapy. This research is directly relevant to furthering the knowledge base in light of HM Government pledging £250 million to build two proton centres in England, to treat NHS patients from 2018. Use of methods described in this dissertation will aid in the establishment of clear and pre-defined protocols for treating patients in the future.
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Neath, Cathy. "Dosimetric evaluation and verification of treatment planning systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ53113.pdf.
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Hodefi, Deborah. "Evaluation of CadPlan for electron beam treatment planning." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80289.
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The electron pencil beam algorithm particular to the CadPlan treatment planning system (Varian) was evaluated for energies and field sizes spanning the clinical range. Calculated distributions were compared to measured data from an Elekta SL 25 linear accelerator. Excellent accordance was achieved between measured and calculated distributions for all energies and field sizes in cases of a uniform medium with a flat surface, perpendicular beam incidence and the standard source to surface distance (SSD) of 100 cm. CadPlan was also proficient at producing accurate distributions involving varied SSDs within the range typically employed in the clinic, 98--102 cm. However, when beam incidence was non-orthogonal to the surface, calculated distributions differed from measurement by up to 2.5 mm or 7%. The most severe discrepancies were observed for larger gantry angles. Calculated percent depth dose (PDD) curves in cases of simple slab heterogeneities were found to deviate from measured curves by at most 1.5 mm. Discontinuities appeared in all CadPlan-predicted curves, worsening in instances of non-standard conditions. Many errors stemming from such discontinuity problems could be eliminated by interpolating between values of fitting parameters tabulated in CadPlan and by offering more pencil beam and calculation grid sizes. As CadPlan has no means of accounting for scattered radiation specific to the jaws and applicator, it is unable to predict output factors with any accuracy.
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Wang, Changgui. "An objective approach to regional wastewater-treatment planning." Thesis, University of Newcastle Upon Tyne, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310027.
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Mathayomchan, Boonyanit. "MULTIOBJECTIVE APPROACH TO MORPHOLOGICAL BASED RADIATION TREATMENT PLANNING." Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1131365356.
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Flower, Emily Elizabeth, and not supplied. "Comparison of Two Planning Methods for Heterogeneity Correction in Planning Total Body Irradiation." RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070511.163728.
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Total body irradiation (TBI) is often used as part of the conditioning process prior to bone marrow transplants for diseases such as leukemia. By delivering radiation to the entire body, together with chemotherapy, tumour cells are killed and the patient is also immunosupressed. This reduces the risk of disease relapse and increases the chances of a successful implant respectively. TBI requires a large flat field of radiation to cover the entire body with a uniform dose. However, dose uniformity is a major challenge in TBI. (AAPM Report 17) The ICRU report 50 recommends that the dose range within the target volume remain in the range of -5% to +7%. Whilst it is generally accepted that this is not possible for TBI, it is normally clinically acceptable that ±10% of the prescribed dose to the whole body is sufficiently uniform, unless critical structures are being shielded. TBI involves complex dosimetry due to the large source to treatment axis distance (SAD), dose uniformity and flatness over the large field, bolus requirements, extra scatter from the bunker walls and floor and large field overshoot. There is also a lack of specialised treatment planning systems for TBI planning at extended SAD. TBI doses at Westmead Hospital are prescribed to midline. Corrections are made for variations in body contour and tissue density heterogeneity in the lungs using bolus material to increase dose uniformity along midline. Computed tomography (CT) data is imported into a treatment planning system. The CT gives information regarding tissue heterogeneity and patient contour. The treatment planning system uses this information to determine the dose distribution. Using the dose ratio between plans with and without heterogeneity correction the effective chest width can be calculated. The effective chest width is then used for calculating the treatment monitor units and bolus requirements. In this project the tissue heterogeneity corrections from two different treatment planning systems are compared for calculating the effective chest width. The treatment planning systems used were PinnacleTM, a 3D system that uses a convolution method to correct for tissue heterogeneity and calculate dose. The other system, RadplanTM, is a 2D algorithm that corrects for tissue heterogeneity using a modified Batho method and calculates dose using the Bentley - Milan Algorithm. Other possible differences between the treatment planning systems are also discussed. An anthropomorphic phantom was modified during this project. The chest slices were replaced with PerspexTM slices that had different sized cork and PerspexTM inserts to simulate different lung sizes. This allowed the effects of different lung size on the heterogeneity correction to be analysed. The phantom was CT scanned and the information used for the treatment plans. For each treatment planning system and each phantom plans were made with and without heterogeneity corrections. For each phantom the ratio between the plans from each system was used to calculate the effective chest width. The effective chest width was then used to calculate the number of monitor units to be delivered. The calculated dose per monitor unit at the extended TBI distance for the effective chest width from each planning system is then verified using thermoluminescent dosimeters (TLDs) in the unmodified phantom. The original phantom was used for the verification measurements as it had special slots for TLDs. The isodose distributions produced by each planning system are then verified using measurements from Kodak EDR2 radiographic film in the anthropomorphic phantom at isocentre. Further film measurements are made at the extended TBI treatment SAD. It was found that only the width of the lungs made any significant difference to the heterogeneity correction for each treatment planning system. The height and depth of the lungs will affect the dose at the calculation point from changes to the scattered radiation within the volume. However, since the dose from scattered radiation is only a fraction of that from the primary beam, the change in dose was not found to be significant. This is because the calculation point was positioned in the middle of the lungs, so the height and depth of the lungs didn't affect the dose at the calculation point. The dose per monitor unit calculated using the heterogeneity correction for each treatment planning system varied less than the accuracy of the TLD measurements. The isodose distributions measured by film showed reasonable agreement with those calculated by both treatment planning systems at isocentre and a more uniform distribution at the extended TBI treatment distance. The verification measurements showed that either treatment planning system could be used to calculate the heterogeneity correction and hence effective chest width for TBI treatment planning.
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Vaidya, Rohit Subhash. "Experimental testing of a computer aided heat treatment planning system." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0827103-111212.
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Vader, Ranjeet D. "Development of computer aided heat treatment planning system (CAHTPS)." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-0830102-113605.
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Kimstrand, Peter. "Beam Modelling for Treatment Planning of Scanned Proton Beams." Doctoral thesis, Uppsala University, Oncology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8640.
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Scanned proton beams offer the possibility to take full advantage of the dose deposition properties of proton beams, i.e. the limited range and sharp peak at the end of the range, the Bragg peak. By actively scanning the proton beam, laterally by scanning magnets and longitudinally by shifting the energy, the position of the Bragg peak can be controlled in all three dimensions, thereby enabling high dose delivery to the target volume only. A typical scanned proton beam line consists of a pair of scanning magnets to perform the lateral beam scanning and possibly a range shifter and a multi-leaf collimator (MLC). Part of this thesis deals with the development of control, supervision and verification methods for the scanned proton beam line at the The Svedberg laboratory in Uppsala, Sweden.
Radiotherapy is preceded by treatment planning, where one of the main objectives is predicting the dose to the patient. The dose is calculated by a dose calculation engine and the accuracy of the results is of course dependent on the accuracy and sophistication of the transport and interaction models of the dose engine itself. But, for the dose distribution calculation to have any bearing on the reality, it needs to be started with relevant input in accordance with the beam that is emitted from the treatment machine. This input is provided by the beam model. As such, the beam model is the link between the reality (the treatment machine) and the treatment planning system. The beam model contains methods to characterise the treatment machine and provides the dose calculation with the reconstructed beam phase space, in some convenient representation. In order for a beam model to be applicable in a treatment planning system, its methods have to be general.
In this thesis, a beam model for a scanned proton beam is developed. The beam model contains models and descriptions of the beam modifying elements of a scanned proton beam line. Based on a well-defined set of generally applicable characterisation measurements, ten beam model parameters are extracted, describing the basic properties of the beam, i.e. the energy spectrum, the radial and the angular distributions and the nominal direction. Optional beam modifying elements such as a range shifter and an MLC are modelled by dedicated Monte Carlo calculation algorithms. The algorithm that describes the MLC contains a parameterisation of collimator scatter, in which the rather complex phase space of collimator scattered protons has been parameterised by a set of analytical functions.
Dose calculations based on the phase space reconstructed by the beam model are in good agreement with experimental data. This holds both for the dose distribution of the elementary pencil beam, reflecting the modelling of the basic properties of the scanned beam, as well as for complete calculations of collimated scanned fields.
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Xian, Zheng. "Dose verification of a stereotactic IMRT treatment planning system." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/23810.
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In this project, ion chamber measurement and film dosimetry were used to verify dose distributions for a new stereotactic IMRT (Intensity Modulated Radiation Therapy) treatment planning system. This technique combines the principles of stereotactic radiosurgery and IMRT to significantly increase the positioning accuracy compared with conventional IMRT . Ion chamber measurements reveal that the discrepancy between the measured and the calculated dose at the isocenter can be up to 2%. Angular dependence of ion chamber sensitivity and the tissue equivalence of the phantom material were determined to be the main sources of this discrepancy. Radiochromic film was used as the film dosimeter in the project. A set of performance tests of Gafchromic EBT film indicated that the uncertainty in Gafchromic EBT film dosimety was expected to be 2.5%. However, the discrepancies we found in measurements of clinical cases using the film were much larger than this. And further investigation into this discrepancy was beyond the scope of this thesis.
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Rowbottom, Carl Graham. "Optimisation of beam-orientations in conformal radiotherapy treatment planning." Thesis, Institute of Cancer Research (University Of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314088.
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Mackin, Neil. "Development of an expert system for planning orthodontic treatment." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238890.
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Battersby, Nicholas John. "Planning treatment and predicting outcomes in low rectal cancer." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/60835.
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Introduction: Low rectal cancer management presents a unique challenge. On one hand more radical measures are required to address poor oncological outcomes and on the other hand there is a need to avoid unacceptably high permanent colostomy rates and suboptimal post-treatment function. This thesis investigates radiological, surgical, pathological and quality of life factors in low rectal cancer, in order to predict outcomes and provide a patient-tailored approach to low rectal cancer management. Methods: The majority of data presented within this thesis will be from the ongoing Low Rectal Cancer Study (MERCURY II). This multidisciplinary study prospectively collected surgical, radiological, pathological and QoL data in consecutive patients undergoing treatment for low rectal cancer. In addition, a multicentre crosssectional quality of life study was performed. This was designed to evaluate post-operative bowel function using patient reported outcome measures (PROMs). Results: Analysis from 279 low rectal cancer patients from the MERCURY II study suggested that MRI assessment of the low rectal plane (mrLRP) guided selection for pre-operative therapy and for restorative resection. MRI assessment contributed to the low (9%, 25/279) pathological circumferential resection margin (pCRM) involvement; significantly lower than the pre-stated target of ≤15% and lower than published studies. Multivariate analysis identified three other predictors for pCRM involvement: tumour ≤4cm from the anal verge; anterior quadrant tumour invasion; and MRI evidence of EMVI. This thesis also validates the English translation of a Danish PROM (LARS score). This data was also used to predict for post-operative bowel-related quality of life (BQoL) impairment following a restorative anterior resection. Finally, the UK LARS data was used to develop a model that predicts post-operative bowel dysfunction (POLARS) with external validation with Danish data. Future Work: The predictors for pCRM involvement require external validation. Future studies should also explore the relationship between these predictors and long-term survival. The POLARS and the LARS score should be used in clinical practice to identify patients who may benefit from additional support for postoperative bowel dysfunction. The value of the post-treatment MRI requires further investigation and the TRIGGER trial has been designed for this purpose.
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Norell, Emil. "Gamma Knife treatment planning with new degrees of freedom." Thesis, KTH, Optimeringslära och systemteori, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-246149.
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The Leksell Gamma Knife® is an instrument designed for high precision treatment of tumours and lesions located in the brain and upper spine. Today, the radioactive cobalt-60 sources can only move linearly along the radiation unit, but the machine could be modified to include rotational motion as well. We extend an existing linear programming approach to inverse planning for the Gamma Knife by examining the benefits from rotational degrees of freedom. The improvements offered from rotations are limited, but easy to make use of. We investigate the model in four patient cases, and find that an upper bound on the improvement of the optimization cost function is between 4.5% and 7.0% depending on case. With a total of four angles distributed uniformly over a 45 degree interval, one can in each case achieve a solution that performs up to within 1% of this bound. The average maximal improvements in terms of clinical metrics are 0.5% selectivity and 1.9% gradient index, at the cost of 5.9% worse beam-on time. No statistically significant change in coverage is found. A dynamic model based on column generation is proposed, which allows treatment during constant velocity angular motion and can achieve practically the same plan quality as the model with uniformly distributed angles at a significantly lower problem size. A similar algorithm can be designed to locate the most effective angles in a non-uniform manner that achieves better plans with fewer added rotational degrees of freedom. Trade-offs between memory and solution times are used to successively reduce the RAM occupation by around 90% and make significantly larger models computationally feasible to solve. A voxel clustering approach with emphasis on surface voxels, adapted to the radiosurgical framework, can significantly reduce the problem size while still producing competitive plans.Strålkniven Leksell Gamma Knife® är ett instrument designat för högprecisionsbestrålning av tumörer och lesioner i hjärnan och övre delen av ryggraden. Idag kan de radioaktiva källorna endast förflyttas linjärt under behandlingen, men maskinen skulle kunna modifieras för att även tillåta rotationsrörelser. Vi utvidgar ett ramverk för inversplanering, formulerat som ett linjär-programmeringsproblem, genom att undersöka fördelarna med nya rotationsfrihetsgrader. Förbättringarna som rotationer möjliggör är begränsade, men kan relativt enkelt tas till vara. Vi undersöker de potentiella förändringarna i fyra patientfall och finner att den övre gränsen av förbättringarna för målfunktionsvärdet i optimeringsproblemet är mellan 4.5% och 7.0% beroende på fall. Genom att tillåta rotation av källorna till fyra jämnt fördelade vinklar över 45 grader kan man i samtliga fall hitta en lösning som är inom 1% från det bästa målfunktionsvärdet. De genomsnittliga förbättringarna i form av kliniska metriker är 0.5% selektivitet och 1.9% gradient-index, dock på bekostnad av en försämring av bestrålningstiden med 5.9%. Ingen tydlig förändring av täckningen kunde påvisas. En modell baserad på kolumngenerering, som tillåter behandling under rotation av kollimator-kroppen med konstant hastighet, föreslås. I denna modell kan praktiskt taget lika bra lösningar uppnås som för likformigt fördelade vinklar, men med betydligt mindre problemstorlek. En liknande algoritm kan lokalisera de mest effektiva vinklarna och åstadkomma samma plankvalitet med färre, men olikformt fördelade, rotationsfrihetsgrader. RAM-användningen kan reduceras med cirka 90% genom avvägningar mellan minne och beräknings-tider, vilket möjliggör lösning av probleminstanser som tidigare var beräkningsmässigt omöjliga. Klustringsmetoder av voxlar anpassade till strålkniven kan minska problemstorleken betydelsefullt medan de resulterande behandlingsplanerna är fortsatt konkurrenskraftiga.
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Haas, O. C. L. "Optimisation and control systems modelling in radiotherapy treatment planning." Thesis, Coventry University, 1997. http://curve.coventry.ac.uk/open/items/fc7aad2f-a43a-4045-adb0-9afa7e9033b3/1.
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Albritton, James Raymond 1977. "Computational aspects of treatment planning for neutron capture therapy." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/57683.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, February 2010.Cataloged from PDF version of thesis.
Includes bibliographical references.
Boron Neutron Capture Therapy (BNCT) is a biochemically targeted form of binary radiation therapy that has the potential to deliver radiation to cancers with cellular dose selectivity. Accurate and efficient treatment planning calculations are essential to maximizing the efficacy of BNCT and ensuring patient safety. This thesis investigates computational aspects of BNCT treatment planning with the aim of improving both the accuracy and efficiency of the planning process as well as developing a better understanding of differences in computational dosimetry that exist between the different BNCT clinical sites around the world. A suite of computational dosimetry reference problems were developed as a basis for comprehensively testing, comparing, and analyzing current and future BNCT treatment planning systems (TPSs) under conditions relevant to both patient planning and planning system calibration. Using these reference problems, four of the TPSs that have been used in clinical BNCT (MacNCTPlan, NCTPlan, BNCTRtpe, and SERA) were compared to reference calculations performed with the well-benchmarked Monte Carlo radiation transport code MCNP5. The comparison of multidimensional dose data in the form of dose profiles, isodose contours, dose difference distributions and dose-volume histograms yielded many clinically significant differences. Additional calculations were performed to further investigate and explain significant deviations from the reference calculations.
(cont.) A combined 81 brain tumor patients have been treated in dose escalation trials of Neutron Capture Therapy (NCT) in the USA at Harvard-Massachusetts Institute of Technology (MIT) and Brookhaven National Laboratory (BNL). Pooling the clinical data from these and other trials will allow the evaluation of the safety and efficacy of NCT with more statistical rigor. However, differences in physical and computational dosimetry between the institutions that make a direct comparison of the clinical dosimetry difficult must first be addressed before clinical data can be compared. This study involves normalizing the BNL clinical dosimetry to that of Harvard-MIT for combined NCT dose response analysis using analysis of MIT measurements and calculations with the BNL treatment planning system (TPS), BNCTRtpe, for two different phantoms. The BNL TPS was calibrated to dose measurements made by MIT at the Brookhaven Medical Research Reactor (BMRR) in the BNL calibration phantom, a Lucite cube, and then validated by MIT dose measurements at the BMRR in an ellipsoidal water phantom. Using the newly determined TPS calibration, treatment plans for all BNL patients were recomputed, yielding reductions in reported mean brain doses of 10% on average in the initial 15 patients treated with the 8 cm collimator and 27% in the latter 38 patients treated with a 12 cm collimator. These reductions in reported doses have clinically significant implications for those relying on reported BNL doses as a basis for initial dose selection in clinical studies and reaffirm the importance of collaborative dosimetric comparisons within the NCT community.
(cont.) The dosimetric adjustments allowed the BNL clinical data to be legitimately combined with the Harvard-MIT clinical data for a combined dose response analysis of the incidence of radiation-induced somnolence syndrome. Probit analysis of the composite data set for the incidence of somnolence yielded ED5o values of 5.76 Gyw and 14.4 Gy, for mean and maximum brain dose. The applicability and optimization of variance reduction techniques for BNCT Monte Carlo treatment planning calculations were investigated using MCNP5. The preexisting variance reduction scheme in the Monte Carlo model of the fission converter beam (FCB) at MIT was optimized, resulting in improved energy-dependent neutron and photon weight windows. Using these weight windows, a more precise surface source representation of the FCB was produced downstream at the patient position with improved statistical properties that increased the mean efficiency of in-phantom dose calculations by a factor of 9. The variance reduction techniques available in MCNP were also explored as a means of increasing the efficiency of dose calculations in the patient model. By disabling implicit neutron capture and using fast neutron source biasing and photon production biasing techniques, the mean efficiency of dose calculations was improved by a factor of 2.2. Constructing an accurate description of a neutron beam is critical to achieving accurate calculations of dose in NCT treatment planning.
(cont.) This study compares two methods of neutron beam source definition commonly used in BNCT treatment planning calculations, the phase space file (MCNP surface source file) and source variable probability distributions (MCNP SDef). To facilitate the comparison, a novel software tool was developed to analyze MCNP surface source files and construct MCNP SDef representations. This tool was applied to the MIT FCB, which has a well-validated Monte Carlo model. Each source type (surface source file and SDef) was used to simulate transport of the beam through voxel models of the modified Snyder head phantom, where doses were calculated. Compared to the surface source file, the initial dose calculations with the SDef produced significant errors of ~15%. Using a patched version of MCNP that allowed the observed radial dependence of the relative azimuthal angle to be modeled in the SDef, errors in all dose components in the head phantom at Dmax were reduced to acceptably small levels with none being statistically significant except for the induced photon error of 0.5%. Errors in the calculated doses introduced by sampling the azimuthal component of particle direction uniformly in the SDef vary spatially, are phantom-dependent, and thus cannot be accurately corrected by a simple scaling of doses.
by James Raymond Albritton.
Ph.D.
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Crews, Joseph MacNeal. "The planning and design of mental health treatment centres." Thesis, University of Greenwich, 1999. http://gala.gre.ac.uk/8730/.
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This research thesis was developed as a planning and design reference for mental health treatment centres. This text is intended to assist planners, designers, and health practitioners to optimize patient health and comfort by providing suitable environments to facilitate care and treatment. This thesis examines and provides guidance on security issues, environmental design, the cognitive environment, and site development. Sample facility plans are also provided to demonstrate the design principles advocated. The foreword examines the historical background of mental health treatment facilities in relation to the context of care. The continuing problem of the alienating and dehumanizing effects of psychiatric hospitals on patients is also addressed. Security requirements are investigated in relation to patients' rights and personal needs. This text also examines related fire safety requirements and design measures to minimize the risks of suicides, self injuries, and assaults. Environmental design issues, including lighting, color, acoustics, construction materials, air quality, and spatial relationships, are examined in relation to mental and physical health. Cognitive issues such as wayfinding, mental maps, symbolism, and perceptions of physical environments and architectural design are explored in relation to mental health treatment facilities. Earlier research suggests that patients have difficulty making the cognitive adjustment to typical mental health treatment facilities, and this can negatively effect their therapy and potential recovery. An illustrated questionnaire was developed to help determine the types of facilities patients can relate to and experience relative comfort. This questionnaire was used to examine perceptions of buildings and designs in relation to the provision of comfortable and healthy environments. The survey revealed that patients, health care providers, and students shared similar perceptions of the built environment, and that buildings possessing features generally associated with domestic buildings (houses) were considered more comfortable than other building types. In particular, buildings with pitched roofs and brick exteriors were considered most suggestive of comfort. Horizontal windows were preferred to more common vertically oriented windows. This effect was more pronounced when windows framed a pleasant natural view. Curved interior forms were also found to be suggestive of comfort. Past, current, and emerging patterns of site and facility development are reviewed in association with their environmental context. The role of nature in the healing process, from ancient Greece to recent discoveries, is also examined. The final chapter of this thesis is a demonstration of design principles with annotated drawings of a hypothetical inpatient unit and outpatient clinic. These drawings are provided to demonstrate an integration of thesis findings and design principles. These drawings are not a definitive design or prototype, because every site and building program are different and require their own design solution.
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Gardner, Joseph Kingsley. "Integration of VMC++ into a Commercial Treatment Planning System." VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd/990.
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Recently, there has been interest to integrate VMC++ into the commercial treatment planning system at VCU as another Monte Carlo code option, since it has been shown to increase efficiency dramatically without introducing a significant amount of systematic error. Also, independent validation of VMC++ for photon beams is of interest since this has not been performed previously in literature. This study included several tests required to integrate VMC++. Output factor normalization was performed and found to agree with experiment to within 1% for all field sizes except 1x1 cm2. Geometric validation was successful. Dosimetric validation was performed with respect to DOSXYZnrc on a water phantom, resulting in agreement within statistical uncertainty except for slight differences at the surface of the phantom. Dosimetric comparison was made for a head-and-neck patient case, showing that 5% of the voxels did not agree within 2.8% of maximum dose. The ability of VMC++ to compute dose-to-water was compared to an in-house algorithm and found to agree within statistical uncertainty.
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Kumar, Arvind. "Novel methods for intensity modulated radiation therapy treatment planning." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011543.
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Zhang, Tianfang. "Machine learning multicriteria optimization in radiation therapy treatment planning." Thesis, KTH, Matematisk statistik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-257509.
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In radiation therapy treatment planning, recent works have used machine learning based on historically delivered plans to automate the process of producing clinically acceptable plans. Compared to traditional approaches such as repeated weighted-sum optimization or multicriteria optimization (MCO), automated planning methods have, in general, the benefits of low computational times and minimal user interaction, but on the other hand lack the flexibility associated with general-purpose frameworks such as MCO. Machine learning approaches can be especially sensitive to deviations in their dose prediction due to certain properties of the optimization functions usually used for dose mimicking and, moreover, suffer from the fact that there exists no general causality between prediction accuracy and optimized plan quality.In this thesis, we present a means of unifying ideas from machine learning planning methods with the well-established MCO framework. More precisely, given prior knowledge in the form of either a previously optimized plan or a set of historically delivered clinical plans, we are able to automatically generate Pareto optimal plans spanning a dose region corresponding to plans which are achievable as well as clinically acceptable. For the former case, this is achieved by introducing dose--volume constraints; for the latter case, this is achieved by fitting a weighted-data Gaussian mixture model on pre-defined dose statistics using the expectation--maximization algorithm, modifying it with exponential tilting and using specially developed optimization functions to take into account prediction uncertainties.Numerical results for conceptual demonstration are obtained for a prostate cancer case with treatment delivered by a volumetric-modulated arc therapy technique, where it is shown that the methods developed in the thesis are successful in automatically generating Pareto optimal plans of satisfactory quality and diversity, while excluding clinically irrelevant dose regions. For the case of using historical plans as prior knowledge, the computational times are significantly shorter than those typical of conventional MCO.Inom strålterapiplanering har den senaste forskningen använt maskininlärning baserat på historiskt levererade planer för att automatisera den process i vilken kliniskt acceptabla planer produceras. Jämfört med traditionella angreppssätt, såsom upprepad optimering av en viktad målfunktion eller flermålsoptimering (MCO), har automatiska planeringsmetoder generellt sett fördelarna av lägre beräkningstider och minimal användarinteraktion, men saknar däremot flexibiliteten hos allmänna ramverk som exempelvis MCO. Maskininlärningsmetoder kan vara speciellt känsliga för avvikelser i dosprediktionssteget på grund av särskilda egenskaper hos de optimeringsfunktioner som vanligtvis används för att återskapa dosfördelningar, och lider dessutom av problemet att det inte finns något allmängiltigt orsakssamband mellan prediktionsnoggrannhet och kvalitet hos optimerad plan. I detta arbete presenterar vi ett sätt att förena idéer från maskininlärningsbaserade planeringsmetoder med det väletablerade MCO-ramverket. Mer precist kan vi, givet förkunskaper i form av antingen en tidigare optimerad plan eller en uppsättning av historiskt levererade kliniska planer, automatiskt generera Paretooptimala planer som täcker en dosregion motsvarande uppnåeliga såväl som kliniskt acceptabla planer. I det förra fallet görs detta genom att introducera dos--volym-bivillkor; i det senare fallet görs detta genom att anpassa en gaussisk blandningsmodell med viktade data med förväntning--maximering-algoritmen, modifiera den med exponentiell lutning och sedan använda speciellt utvecklade optimeringsfunktioner för att ta hänsyn till prediktionsosäkerheter.Numeriska resultat för konceptuell demonstration erhålls för ett fall av prostatacancer varvid behandlingen levererades med volymetriskt modulerad bågterapi, där det visas att metoderna utvecklade i detta arbete är framgångsrika i att automatiskt generera Paretooptimala planer med tillfredsställande kvalitet och variation medan kliniskt irrelevanta dosregioner utesluts. I fallet då historiska planer används som förkunskap är beräkningstiderna markant kortare än för konventionell MCO.
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Staley, Noah D. "An Investigation into the Accuracy of the Photon Beam Energy Spectrum Modeled by the Pinnacle Treatment Planning System and Its Effects on Treatment Planning." University of Toledo Health Science Campus / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=mco1481308003486075.
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Tuncer, Ozgur. "Segmentation, Registration And Visualization Of Medical Images For Treatment Planning." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1093368/index.pdf.
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Medical imaging has become the key to access inside human body for the
purpose of diagnosis and treatment planning. In order to understand the
effectiveness of planned treatment following the diagnosis, treated body part may
have to be monitored several times during a period of time. Information gained
from successive imaging of body part provides guidance to next step of treatment.
Comparison of images or datasets taken at different times requires registration of
these images or datasets since the same conditions may not be provided at all
times. Accurate segmentation of the body part under treatment is needed while
comparing medical images to achieve quantitative and qualitative measurements.
This segmentation task enables two dimensional and three dimensional
visualizations of the region which also aid in directing the planning strategy.
In this thesis, several segmentation algorithms are investigated and a hybrid
segmentation algorithm is developed in order to segment bone tissue out of head
CT slices for orthodontic treatment planning. Using the developed segmentation algorithm, three dimensional visualizations of segmented bone tissue out of head
CT slices of two patients are obtained. Visualizations are obtained using the
MATLAB Computer software’
s visualization library. Besides these, methods are developed for automatic registration of twodimensional and three-dimensional CT images taken at different time periods. These methods are applied to real and synthetic data. Algorithms and methods used in this thesis are also implemented in MATLAB computer program.
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Rødal, Jan. "On functional imaging and treatment planning for biologically adapted radiotherapy." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16154.
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Tumours show large variations in response to radiotherapy, both across tumour types and within individual tumours. One way to counteract radioresistance is to increase the radiation dose to resistant regions by so-called biologically adapted therapy. Visualisation of these regions based on properties related to radioresistance, such as metabolism, hypoxia, proliferation, and vascularisation, can act as basis for target definition, and can be obtained by PET/CT, dynamic MRI, and dynamic CT imaging. One aim of the present work was to improve tumour visualisation in images obtained before and during radiotherapy. An analysis of dynamic FDG-PET (D-PET) and dynamic contrast-enhanced CT (DCE-CT) images of three canine patients showed similarities between the two image modalities with respect to tumour vascularisation. The results indicated that D-PET may be used alone for assessment of both tumour perfusion and metabolic activity, simplifying the image acquisition. We also investigated a new method for tumour visualisation by use of image subtraction in CE cone-beam CT (CE-CBCT) images, obtained during IMRT of one of the dogs. The method was shown to be feasible and produced images with a clearly visualised tumour. We further aimed to investigate the radiobiological effect of biologically adapted dose delivery. An IMRT planning study based on CE-CBCT images of the first canine IMRT patient demonstrated that such dose planning was feasible. This approach gave the highest effect on the tumour and thus showed that biologically adapted treatment was the best choice for this treatment case. Furthermore, a hypoxia dose painting study with a highly heterogeneous tumour model, where MLC leaf widths and IMRT parameters were varied, indicated that reducing the leaf widths from 10 to 5 or 2.5 mm gave increased tumour control probability. We also implemented dose painting by contours in an anthropomorphic phantom. An optimal dose delivery was not achieved. In conclusion, dynamic FDG-PET before radiotherapy and CE-CBCT during radiotherapy may be valuable. Dose painting should preferably be delivered by MLCs with small leaf widths. However, a high radiobiological effect from high-resolution dose painting could not be demonstrated in practice. An alternative dose painting approach or treatment modality may thus be required for biologically adapted dose delivery to highly heterogeneous tumours.
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Kwa, William. "Asymmetric collimation : dosimetric characteristics, treatment planning algorithm, and clinical applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/nq27182.pdf.
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Bokrantz, Rasmus. "Multicriteria optimization for managing tradeoffs in radiation therapy treatment planning." Doctoral thesis, KTH, Optimeringslära och systemteori, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122663.
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Treatment planning for radiation therapy inherently involves tradeoffs, such as between tumor control and normal tissue sparing, between time-efficiency and dose quality, and between nominal plan quality and robustness. The purpose of this thesis is to develop methods that can facilitate decision making related to such tradeoffs. The main focus of the thesis is on multicriteria optimization methods where a representative set of treatment plans are first calculated and the most appropriate plan contained in this representation then selected by the treatment planner through continuous interpolation between the precalculated alternatives. These alternatives constitute a subset of the set of Pareto optimal plans, meaning plans such that no criterion can be improved without a sacrifice in another. Approximation of Pareto optimal sets is first studied with respect to fluence map optimization for intensity-modulated radiation therapy. The approximation error of a discrete representation is minimized by calculation of points one at the time at the location where the distance between an inner and outer approximation of the Pareto set currently attains its maximum. A technique for calculating this distance that is orders of magnitude more efficient than the best previous method is presented. A generalization to distributed computational environments is also proposed. Approximation of Pareto optimal sets is also considered with respect to direct machine parameter optimization. Optimization of this form is used to calculate representations where any interpolated treatment plan is directly deliverable. The fact that finite representations of Pareto optimal sets have approximation errors with respect to Pareto optimality is addressed by a technique that removes these errors by a projection onto the exact Pareto set. Projections are also studied subject to constraints that prevent the dose-volume histogram from deteriorating. Multicriteria optimization is extended to treatment planning for volumetric-modulated arc therapy and intensity-modulated proton therapy. Proton therapy plans that are robust against geometric errors are calculated by optimization of the worst case outcome. The theory for multicriteria optimization is extended to accommodate this formulation. Worst case optimization is shown to be preferable to a previous more conservative method that also protects against uncertainties which cannot be realized in practice.En viktig aspekt av planering av strålterapibehandlingar är avvägningar mellan behandlingsmål vilka står i konflikt med varandra. Exempel på sådana avvägningar är mellan tumörkontroll och dos till omkringliggande frisk vävnad, mellan behandlingstid och doskvalitet, och mellan nominell plankvalitet och robusthet med avseende på geometriska fel. Denna avhandling syftar till att utveckla metoder som kan underlätta beslutsfattande kring motstridiga behandlingsmål. Primärt studeras en metod för flermålsoptimering där behandlingsplanen väljs genom kontinuerlig interpolation över ett representativt urval av förberäknade alternativ. De förberäknade behandlingsplanerna utgör en delmängd av de Paretooptimala planerna, det vill säga de planer sådana att en förbättring enligt ett kriterium inte kan ske annat än genom en försämring enligt ett annat. Beräkning av en approximativ representation av mängden av Paretooptimala planer studeras först med avseende på fluensoptimering för intensitetsmodulerad strålterapi. Felet för den approximativa representationen minimeras genom att innesluta mängden av Paretooptimala planer mellan inre och yttre approximationer. Dessa approximationer förfinas iterativt genom att varje ny plan genereras där avståndet mellan approximationerna för tillfället är som störst. En teknik för att beräkna det maximala avståndet mellan approximationerna föreslås vilken är flera storleksordningar snabbare än den bästa tidigare kända metoden. En generalisering till distribuerade beräkningsmiljöer föreslås även. Approximation av mängden av Paretooptimala planer studeras även för direkt maskinparameteroptimering, som används för att beräkna representationer där varje interpolerad behandlingsplan är direkt levererbar. Det faktum att en ändlig representation av mängden av Paretooptimala lösningar har ett approximationsfel till Paretooptimalitet hanteras via en metod där en interpolerad behandlingsplan projiceras på Paretomängden. Projektioner studeras även under bivillkor som förhindrar att den interpolerade planens dos-volym histogram kan försämras. Flermålsoptimering utökas till planering av rotationsterapi och intensitetsmodulerad protonterapi. Protonplaner som är robusta mot geometriska fel beräknas genom optimering med avseende på det värsta möjliga utfallet av de föreliggande osäkerheterna. Flermålsoptimering utökas även teoretiskt till att innefatta denna formulering. Nyttan av värsta fallet-optimering jämfört med tidigare mer konservativa metoder som även skyddar mot osäkerheter som inte kan realiseras i praktiken demonstreras experimentellt.
QC 20130527
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Orfali, Anas. "Verification of a 3D external photon beam treatment planning system." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24374.
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Treatment planning is recognized as a fundamental step in clinical radiotherapy. The increased availability and complexity of three dimensional (3D) computerized treatment planning systems necessitates a full verification protocol to be completed prior to the implementation of the treatment planning system in routine use.We have designed and performed a detailed experimental verification program aimed at evaluating each individual dosimetric aspect of our 3D computerized treatment planning system (Varian CADPLAN, version 2.62). The verification tests ranged in complexity from the most basic standard geometry to a simulation of a full treatment case. Results from each individual testing geometry are presented, and an overall evaluation is discussed. We have concluded that our 3D treatment planning system is acceptable for clinical use.
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Al-Yahya, Khalid S. "Implementation of Monte Carlo treatment planning for lung cancer patients." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29412.
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Current dose photon calculation algorithms have shortcomings in calculating dose distributions accurately in complex, heterogeneous phantoms. In this work, using existing Monte Carlo (MC) algorithms, we implemented and validated a comprehensive MC treatment planning system (MCTPS). We compared MCTPS with the corrected pencil beam algorithm used in the commercial TPS, CadPlan (V2.7.3). The accuracy of dose distributions calculated by MCTPS was studied for six lung cancer patients in two modes: without correction for inhomogeneity (the clinically used method) and with the equivalent tissue air ratio (EgTAR) inhomogeneity correction switched on. Without the use of inhomogeneity corrections, absorbed dose estimated by CadPlan is in error by more than 10% in the planning target volume (PTV). With the EgTAR correction, good agreement was observed for the dose to the PTV, however, in regions close to an interface, where a significant density gradient occurs, the error is up to 10%. Dose errors in other organs were studied using differential dose volume histograms.
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Obata, Yasunori, and Hiroshi Oguchi. "Commissioning of modulator-based IMRT with XiO treatment planning system." AIP Publishing, 2009. http://hdl.handle.net/2237/20613.
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Aly, Moamen. "The application of positron emission tomography in radiotherapy treatment planning." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/the-application-of-positron-emission-tomography-in-radiotherapy-treatment-planning(23a8d56c-c6da-4e3f-a27e-6ecbc979c86e).html.
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Positron emission tomography (PET) is a molecular imaging technique that provides a direct and accurate evaluation of tissue function in vivo. PET of the glucose analogue 18F-fluoro-deoxy-glucose, is increasingly in use to aid in gross target volume delineation in radiotherapy treatment planning (RTP) where it shows reduced inter-observer variability. The aim of this thesis was to develop and investigate a new technique for delineating PET-GTV with sufficient accuracy for RTP. A new technique, volume and contrast adjusted thresholding (VCAT), has been developed to automatically determine the optimum threshold value that measures the true volume on PET images. The accuracy was investigated in spherical and irregular lesions in phantoms using both iterative and filtered back-projection reconstructions and different image noise levels. The accuracy of delineation for the irregular lesions was assessed by comparison with CT using the Dice Similarity Coefficient and Euclidean Distance Transformation. A preliminarily investigation of implementing the newly developed technique in patients was carried out. VCAT proved to determine volumes and delineate tumour boundaries on PET/CT well within the acceptable errors for radiotherapy treatment planning irrespective of lesion contrast, image noise level and reconstruction technique.
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Men, Chunhua. "Optimization models for radiation therapy treatment planning and patient scheduling /." [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0025021.
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Mason, Joshua William. "Advanced dose calculations and imaging in prostate brachytherapy treatment planning." Thesis, University of Leeds, 2014. http://etheses.whiterose.ac.uk/7623/.
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Brachytherapy using low dose rate (LDR) permanent seed implant or high dose rate (HDR) temporary implant is a well established treatment for prostate cancer. This study investigates the use of advanced dose calculation and imaging techniques to improve clinical prostate brachytherapy treatments. Monte Carlo (MC) simulations are used to assess the impact of source interactions and tissue composition effects that are ignored by the TG-43U1 dose calculation algorithm used in clinical practice. MC simulation results are validated using experimental phantom measurements. The development of prostate cancer may be driven by a dominant intra-prostatic lesion (DIL) but standard brachytherapy treatments prescribe the same dose level to the whole prostate. This study assesses the feasibility of multi-parametric (mp-MRI) guided focal boost treatments that escalate dose to the DIL to improve tumour control and of focal treatments that target the DIL to reduce treatment related side effects. Source interactions and tissue effects are shown to reduce the dose that is delivered to patients in LDR treatments, particularly for patients with calcifications, however the dosimetric impact is small compared to other uncertainties in LDR seed implant brachytherapy. For HDR treatments attenuation by steel catheters has only a small impact on dose distributions. Feasibility of mp-MRI guided focal boost HDR prostate brachytherapy is demonstrated in terms of tumour delineation and the ability to dose escalate the DIL without increased dose to normal tissues. The dosimetric feasibility of LDR and HDR focal therapy treatments is demonstrated. Focal therapy treatments are shown to be more sensitive to source position errors than whole gland treatments. MC simulations of focal therapy treatments show that there are no additional concerns in terms of dosimetric accuracy compared to standard whole gland treatments. Advanced dose calculation and imaging techniques can improve clinical prostate brachytherapy treatments.
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Jonsson, Joakim H., Magnus G. Karlsson, Mikael Karlsson, and Tufve Nyholm. "Treatment planning using MRI data: an analysis of the dose calculation accuracy for different treatment regions." Umeå universitet, Radiofysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-35610.
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BACKGROUND: Because of superior soft tissue contrast, the use of magnetic resonance imaging (MRI) as a complement to computed tomography (CT) in the target definition procedure for radiotherapy is increasing. To keep the workflow simple and cost effective and to reduce patient dose, it is natural to strive for a treatment planning procedure based entirely on MRI. In the present study, we investigate the dose calculation accuracy for different treatment regions when using bulk density assignments on MRI data and compare it to treatment planning that uses CT data. METHODS: MR and CT data were collected retrospectively for 40 patients with prostate, lung, head and neck, or brain cancers. Comparisons were made between calculations on CT data with and without inhomogeneity corrections and on MRI or CT data with bulk density assignments. The bulk densities were assigned using manual segmentation of tissue, bone, lung, and air cavities. RESULTS: The deviations between calculations on CT data with inhomogeneity correction and on bulk density assigned MR data were small. The maximum difference in the number of monitor units required to reach the prescribed dose was 1.6%. This result also includes effects of possible geometrical distortions. CONCLUSIONS: The dose calculation accuracy at the investigated treatment sites is not significantly compromised when using MRI data when adequate bulk density assignments are made. With respect to treatment planning, MRI can replace CT in all steps of the treatment workflow, reducing the radiation exposure to the patient, removing any systematic registration errors that may occur when combining MR and CT, and decreasing time and cost for the extra CT investigation.
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Alshamrany, Abdullah. "Determination Of Dose Effects When Including Attenuation Of The Treatment Table Into Treatment Planning Computer Modeling." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1520859358953399.
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Garland, Adam D. "The Effectiveness of Utilizing the Treatment Support Measure for Treatment Planning in Youth Mental Health Services." BYU ScholarsArchive, 2017. https://scholarsarchive.byu.edu/etd/6591.
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The use of treatment support tools to enhance client outcomes is not well understood in the youth treatment literature. Adult outcome researchers have found that the use of Clinical Support Tools (CST) leads to improved outcomes with clients identified as at risk for treatment failure. However, the American Psychological Association (APA) has noted that understanding important client factors that influence treatment is critical during the clinical formulation and treatment planning phase of therapy. No studies to date have evaluated the effectiveness of utilizing a CST as a treatment planning tool with youth clients. The purpose of this study was to evaluate the effectiveness of the Treatment Support Measure, a CST, for the purpose of treatment planning rather than as a reaction to clients who became at-risk for treatment failure. Two hundred and eight youth participants and their caregivers from three outpatient community mental health clinics were randomly assigned to a feedback (TSM-FB) or Non-FB condition. All participants completed the Youth Outcome Questionnaire (Y-OQ) at each session. The TSM was administered to clients in the TSM-FB condition during the intake session. Only therapists whose clients were in the TSM-FB condition received TSM and Y-OQ data. A multilevel model was created to evaluate for differences between conditions on the dependent variable. The initial randomization failed to create similar groups at intake and a statistically and clinically significant difference was detected on the Y-OQ at intake. As such, no conclusions can be drawn for hypotheses tied to the primary dependent variable. Premature termination (PT) rates were significantly lower for the TSM-FB condition when defined as attending more than one session. Contrastingly, there was no difference between conditions on PT when defining PT based on the therapist's opinion. A significant minority of therapists (40%) found that the TSM was useful for treatment planning compared to 10% which did not.
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Miller, William Harley. "AN INTRODUCTION TO A HYPERTHERMIA PATIENT PLANNING AND PATIENT TREATMENT EVALUATION SYSTEM (NUMERICAL, CANCER)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275373.
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Nill, Simeon. "Development and application of a multi-modality inverse treatment planning system." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963121413.
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Orlowski, Piotr. "Treatment planning for the embolization of arteriovenous malformations of the brain." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669969.
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Beckham, Wayne Allan. "Application of magnetic resonance imaging to radiotherapy treatment planning and neurosurgery /." Title page and table of contents only, 1997. http://web4.library.adelaide.edu.au/theses/09PH/09phb397.pdf.
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Mitrou, Ellis. "Monte Carlo based electron treatment planning and cutout output factor calculations." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106456.
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Electron radiotherapy (RT) offers a number of advantages over photons. The high surface dose, combined with a rapid dose fall-off beyond the target volume presents a net increase in tumor control probability and decreases the normal tissue complication for superficial tumors. Electron treatments are normally delivered clinically without previously calculated dose distributions due to the complexity of the electron transport involved and greater error in planning accuracy. This research uses Monte Carlo (MC) methods to model clinical electron beams in order to accurately calculate electron beam dose distributions in patients as well as calculate cutout output factors, reducing the need for a clinical measurement. The present work is incorporated into a research MC calculation system: McGill Monte Carlo Treatment Planning (MMCTP) system. Measurements of PDDs, profiles and output factors in addition to 2D GAFCHROMIC EBT2 film measurements in heterogeneous phantoms were obtained to commission the electron beam model. The use of MC for electron TP will provide more accurate treatments and yield greater knowledge of the electron dose distribution within the patient. The calculation of output factors could invoke a clinical time saving of up to 1 hour per patient.La radiotherapie d'électrons offre plusieurs avantages en comparaison avec les photons. La dose de surface élevée, en combinaison avec une dose descendante plus rapide au-delà du volume prévu présente un taux plus élevé de la probabilité de contrôle tumoral et diminue les complications dans les tissus normaux en évitant les tumeurs superficiel. Les traitements d'électrons sont habituellement utilisés cliniquement sans calculations de doses prévu, due à leurs complexités du transport d'électron qui sont impliqués et plusieurs erreurs de precision en planification. Cette recherche utilise les methodes de Monte Carlo (MC) pour démontrer cliniquement les faisceaux d'électrons pour précisément calculer la dose d'électron distribuée au patients mais aussi pour pouvoir calculer les facteurs de dendements de cutout, et ceci réduit le besoin d'une mesure clinique. Ce projet a été élaboré dans un environnement de calculation par MC: McGill Monte Carlo Treatment Planning (MMCTP) System. Mesure de pourcentage de dose en profondeur, profiles et les facteurs de rendements de cutout ainsi que de doses mesurés avec des films GAFCHROMIC EBT2 dans les phantoms hétérogène ont été obtenu pour déléguer la modèle de faisceau d'électron. L'utilisation de MC pour l'électrode TP sera apporter des traitements plus précis et en consequence produire plus de connaissance de la dose d'electrons plus approprié pour le patient. Ces attributions pourront sauver jusqu'à une heure par patient en terme de temps passé en clinique.
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Bazalova, Magdalena. "The use of computed tomography images in Monte Carlo treatment planning." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32513.
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Monte Carlo (MC) dose calculations cannot accurately assess the dose delivered to the patient during radiotherapy unless the patient anatomy is well known. This thesis focuses on the conversion of patient computed tomography (CT) images into MC geometry files. Metal streaking artifacts and their effect on MC dose calculations are first studied. A correction algorithm is applied to artifact-corrupted images and dose errors due to density and tissue mis-assignment are quantified in a phantom and a patient study. The correction algorithm and MC dose calculations for various treatment beams are also investigated using phantoms with real hip prostheses. As a result of this study, we suggest that a metal artifact correction algorithm should be a part of any MC treatment planning. By means of MC simulations, scatter is proven to be a major cause of metal artifacts. The use of dual-energy CT (DECT) for a novel tissue segmentation scheme is thoroughly investigated. First, MC simulations are used to determine the optimal beam filtration for an accurate DECT material extraction. DECT is then tested on a CT scanner with a phantom and a good agreement in the extraction of two material properties, the relative electron density rho_e and the effective atomic number Z is found. Compared to the conventional tissue segmentation based on rho_e-differences, the novel tissue segmentation scheme uses differences in both rho_e and Z. The phantom study demonstrates that the novel method based on rho_e and Z information works well and makes MC dose calculations more accurate. This thesis demonstrates that DECT suppresses streaking artifacts from brachytherapy seeds. Brachytherapy MC doseLes calculs de dose Monte Carlo (MC) ne peuvent précisément déterminer la dose délivrée au patient, à moins de bien connaître son anatomie. Cette thèse se concentre sur la conversion des images tomographiques du patient en fichier de géométrie Monte Carlo. Les artefacts métalliques et leur effet sur les calculs de dose MC sont étudiés. Un algorithme de correction est appliqué sur les images avec artefacts et les erreurs de dose dues au mauvais assignement des densités et tissus sont quantifiées dans un fantôme et une étude de patient. L'algorithme de correction est aussi testé sur des fantômes avec de réelles prothèses de hanches et l'effet de correction sur les calculs de dose MC est étudié. En tant que résultat de cette étude, nous suggérons qu'un algorithme de correction des artefacts métalliques soit intégré à tout plan de traitement MC. Par le biais de simulations MC, le diffusé est prouvé être une cause majeure des artefacts métalliques. L'utilisation d'un scanner double énergie pour une méthode novatrice de segmentation de tissu est minutieusement étudiée. Tout d'abord, les simulations MC sont utilisées pour déterminer la filtration optimale de faisceau pour une extraction précise du matériau en scanner double énergie. La méthode à double énergie est ensuite testée sur un scanner avec un fantôme et un bon accord dans l'extraction des propriétés des deux matériaux, la densité électronique relative rho_e et le nombre effectif atomique Z est trouvé. Comparé à la segmentation conventionnelle des tissus réalisée sur la base des différents rho_e, la méthode novatrice de segmentation de tissu utilise les diff
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Bandeira, de Oliveira Patricia. "Comparing two methods of surgical treatment planning with mini dental implants." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114551.
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Objective: This study evaluated the discrepancies between dental implant treatment planning for surgical guide fabrication using Cone Beam Computerized Tomography (CBCT) with imaging software and a Conventional method based on anatomic landmarks and prosthetic design. Methods: Based on anatomical landmarks in the interforaminal area, four metal guiding sleeves were installed in radiographic templates fabricated on mandibular casts for placement of 64 implants in 16 patients (n=16). Each patient enrolled in the study underwent a CBCT scan with the template in the mouth. The metal sleeves were identified in the tomogram, and their positions were compared to the positions of implants virtually determined with the implant treatment planning software. Using specific tools provided by the software, differences in bony entrance points and angulations, in the mesial-distal and labial-lingual directions, were measured for each implant. Median differences were compared using Wilcoxon signed rank test for clustered data. Results: Median differences (interquartile ranges) of the entrance points based either on anatomical landmarks or imaging software were 0.8 (±0.0–0.85) mm in the mesial-distal direction and 0.7 (±0.0–5.0) mm in the lingual-labial direction (p<0.001). A significant angle difference was observed between the two methods in the mesial-distal and labial-lingual directions (p<0.001). The median (interquartile range) differences in angulations between the two methods were 2.2 (0.0–10.05) degrees and 4.9 (0.0–18.7) degrees (p<0.001), respectively. Conclusion: Planning the placement of implants using CBCT imaging software leads to different implant location and angulations than with conventional treatment planning based on anatomical landmarks; these differences may have an impact on clinical outcomes.Objectif : Cette étude évalue les différences entre la planification de traitements avec implants dentaires utilisant un guide chirurgical fabriqué à l'aide de la tomographie volumétrique numérisée 3D (Cone Beam Computed Tomography, CBCT) et d'un logiciel d'imagerie, et l'utilisation d'une méthode conventionnelle basée sur des repères anatomiques et sur la conception de prothèses. Méthodes: En se basant sur des repères anatomiques de la région interforaminale, quatre manches métalliques servant de guide ont été installés dans des modèles de radiographie fabriqués sur moule mandibulaire pour le placement de 64 implants chez 16 patients (n = 16). Chaque patient participant à l'étude a passé un examen CBCT avec le modèle dans la bouche. Les manches en métal ont été localisées sur le scan, et leurs positions ont été comparées aux positions d'implants déterminées avec le logiciel de planification d'implants. En utilisant des outils spécifiques fournis par le logiciel, les différences entre les points d'entrée osseux ainsi que les angulations, dans les directions mésio-distale et bucco-linguale, ont été mesurées pour chaque implant. Les différences médianes ont été comparées en utilisant le test des rangs signés de Wilcoxon pour échantillons appariés. Résultats: Les différences médianes (intervalles interquartiles) des points d'entrée basés soit sur la méthode des repères anatomiques ou la méthode du logiciel d'imagerie étaient de 0,8 (0,0 à 0,85) mm dans le sens mésio-distal et 0,7 (0,0 à 5,0) mm dans la direction linguale-labiale (p<0,001). Une différence d'angle significative a été observée entre les deux méthodes dans les directions mésio-distale et labial-linguale (p<0,001). Les différences médianes (intervalle interquartile) des angulations entre les deux méthodes étaient de 2,2 (0,0 à 10,05) degrés et 4,9 (0,0 à 18,7) degrés (p<0,001) respectivement. Conclusion: La planification du placement des implants à l'aide d'un logiciel d'imagerie CBCT a pour résultat une variation dans le positionnement et l'angulation des implants en comparaison à la planification du traitement en utilisant la méthode conventionnelle basée sur les points de repère anatomiques. Ces différences peuvent avoir un impact sur les résultats cliniques.
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Wilson, Dale Louise. "An improved planning protocol for the endovascular treatment of intracranial aneurysms." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298720.
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