Bibliografie tematiche / Linear accelerators in medicine

Letteratura scientifica selezionata sul tema "Linear accelerators in medicine"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 29 gennaio 2023

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Articoli di riviste sul tema "Linear accelerators in medicine"

Vorogushin, M. F., Yu N. Gavrish, M. I. Demskii, V. M. Nikolaev, Yu V. Myasnikov, V. I. Petrunin e S. A. Ogorodnikov. "Linear electron accelerators for industry and medicine". Atomic Energy 87, n. 2 (agosto 1999): 596–600. http://dx.doi.org/10.1007/bf02673225.

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Kalinić, Venera, Dragan Babić, Inga Marijanović e Darjan Franjić. "LINEAR ACCELERATORS IN TELERADIOTHERAPY". Zdravstveni glasnik, n. 16 (30 novembre 2022): 67–76. http://dx.doi.org/10.47960/2303-8616.2022.16.67.

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Vretenar, M., A. Mamaras, G. Bisoffi e P. Foka. "Production of radioisotopes for cancer imaging and treatment with compact linear accelerators". Journal of Physics: Conference Series 2420, n. 1 (1 gennaio 2023): 012104. http://dx.doi.org/10.1088/1742-6596/2420/1/012104.

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Abstract Accelerator-produced radioisotopes are widely used in modern medicine, for imaging, for cancer therapy, and for combinations of therapy and diagnostics (theragnostics). Clinical trials are well advanced for several radioisotope-based treatments that might open the way to a strong request of specific accelerator systems dedicated to radioisotope production. While cyclotrons are the standard tool in this domain, we explore here alternative options using linear accelerators. Compared to cyclotrons, linacs have the advantage of modularity, compactness, and reduced beam loss with lower shielding requirements. Although in general more expensive than cyclotrons, linacs are competitive in cost for production of low-energy proton beams, or of intense beams of heavier particles. After a review of radioisotopes of potential interest, in particular produced with low-energy protons or helium, this paper presents two linac-based isotope production systems. The first is a compact RFQ-based system for PET (Positron Emission Tomography) isotopes, and the second is an alpha-particle linac for production of alpha-emitters. The accelerator systems are described, together with calculations of production yields for different targets.

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Vladimir Kuzmich Shilov, Aleksandr Nikolaevich Filatov e Aleksandr Evgenevich Novozhilov. "High frequency power supply to improve operation stability of linear electron accelerator". Nexo Revista Científica 34, n. 04 (28 ottobre 2021): 1515–20. http://dx.doi.org/10.5377/nexo.v34i04.12697.

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The use of linear electron accelerators in medicine and industry is explained by the simplicity of the input and output of accelerated electrons and adjusting the energy and dose rate, as well as the high dose rate of bremsstrahlung. The purpose of this work is to increase the stability of their work. A standing wave accelerator containing a high-frequency generator, a phase shifter, a waveguide bridge, a high-frequency load, and an accelerating system of two accelerating sections is equipped with two waveguide tees. Their inputs are connected to the output arms of the waveguide bridge, and the first and second output arms of each tee are connected to the first and last accelerating cells of each section, respectively. In this system, due to the introduction of several elements that do not require large costs for manufacturing and tuning, a significantly greater frequency separation of the operating mode of oscillations from neighboring ones is ensured, or even a single-frequency excitation mode is implemented, which makes it possible to significantly increase the stability of the accelerator operation. This technique can be used to increase the stability of operation in the design and calculation of linear accelerators of electrons with a standing wave.

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Bradshaw, A. L. "Linear Accelerators for Radiation Therapy". Physics Bulletin 37, n. 4 (aprile 1986): 176. http://dx.doi.org/10.1088/0031-9112/37/4/032.

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Shilov, Vladimir Kuz'mich, Aleksandr Nikolaevich Filatov e Aleksandr Evgen'evich Novozhilov. "Focusing Properties of a Modified Retarding Structure for Linear Electron Accelerators". International Journal of Electrical and Computer Engineering (IJECE) 7, n. 2 (1 aprile 2017): 741. http://dx.doi.org/10.11591/ijece.v7i2.pp741-747.

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When using accelerators in industry and medicine, important are the dimensions of the device used, especially the radial ones. In the linear electron accelerators based on a biperiodic retarding structure, which operates in the standing wave mode, there is a possibility to provide focusing of the accelerated particles with the help of high-frequency fields without the use of external focusing elements. In the accelerating cell, due to the presence of the far protruding drift sleeves, the electric field lines become strongly curved, which leads to the appearance in the regions adjacent to these sleeves of a substantial in magnitude radial component of the electric field. The particles entering the accelerating gap experience the action of a force directed toward the axis of the system, and at the exit, of a force directed away from the axis. Under certain conditions, alternation of the focusing and defocusing fields can lead to a general focusing effect. In the paper we study the focusing properties of a modified biperiodic structure with standing wave. The main attention is paid to the possibility of using the focusing properties of the electromagnetic accelerating field for guiding the electron beam through the aperture of the accelerating system, which will lead to a significant reduction in the accelerator sizes. The proposed method can be applied in the calculation and design of linear electron accelerators.

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Greene, D., e P. Fallas. "Long-term performance of linear accelerators". British Journal of Radiology 58, n. 690 (giugno 1985): 556–57. http://dx.doi.org/10.1259/0007-1285-58-690-556.

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McDermott, Patrick N. "Photon skyshine from medical linear accelerators". Journal of Applied Clinical Medical Physics 21, n. 3 (marzo 2020): 108–14. http://dx.doi.org/10.1002/acm2.12833.

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Konefał, Adam, Andrzej Orlef e Maria Sokół. "Application of therapeutic linear accelerators for the production of radioisotopes used in nuclear medicine". Polish Journal of Medical Physics and Engineering 28, n. 3 (28 luglio 2022): 107–16. http://dx.doi.org/10.2478/pjmpe-2022-0013.

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Abstract This review paper summarizes the possibilities of the use of therapeutic linear electron accelerators for the production of radioisotopes for nuclear medicine. This work is based on our published results and the thematically similar papers by other authors, directly related to five medical radioisotopes as 99Mo/99mTc, 198Au, 186Re, 188Re, 117mSn, produced using therapeutic linacs. Our unpublished data relating to the issues discussed have also been used here. In the experiments, two types of radiation were included in the analysis of the radioisotope production process, i.e. the therapeutic twenty-megavolt (20 MV) X-rays generated by Varian linacs and neutron radiation contaminating the therapeutic beam. Thus, the debated radioisotopes are produced in the photonuclear reactions and in the neutron ones. Linear therapeutic accelerators do not allow the production of radioisotopes with high specific activities, but the massive targets can be used instead. Thus, the amount of the produced radioisotopes may be increased. Apart from linear accelerators, more and more often, the production of radioisotopes is carried out in small medical cyclotrons. More such cyclotrons are developed, built, and sold commercially than for scientific research. The radioisotopes produced with the use of therapeutic linacs or cyclotrons can be successfully applied in various laboratory tests and in research.

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Velten, Christian, Yi‐Fang Wang, John Adamovics e Cheng‐Shie Wuu. "3D isocentricity analysis for clinical linear accelerators". Medical Physics 47, n. 4 (14 febbraio 2020): 1460–67. http://dx.doi.org/10.1002/mp.14039.

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Tesi sul tema "Linear accelerators in medicine"

Klick, George. "High-technology, high energy medical linear accelerators : a review of contemporary problems". Thesis, Queensland University of Technology, 1989. https://eprints.qut.edu.au/35939/1/35939_Klick_1989.pdf.

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The original aim of this project was to study the factors affecting the decision to adopt high energy linear accelerators. including administrative. technical and cltnical aspects. However the potential enormity of the task soon became evident resulting in limitations being placed on the scope of the study. The group of topics finally chosen as the basis for this review-study (listed below) were principally derived from those nominated in the paper by Drew (1987): 1. Optimum Accelerator Energy 2. Aspects of Photon and Electron Dosimetry 3. Dose Delivery Errors 4. Computer Control Systems Reliability 5. Problems with Neutrons at High Energies Each of the above topics is covered in varying degrees of detail which is justified in that the assumed target audience would have some medical physics background but not necessartly at a professional level in radiotherapy. As a result some sections include broader background material. for example NCRP 79 ( 1984) was relied on extensively to introduce the various sections of the neutron aspect of high energy accelerators, following which a review of more recent material is presented.

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Delaney, Geoffrey Paul SWSAHS Clinical School UNSW. "The Development of a New Measure of Linear Accelerator Throughput in Radiation Oncology Treatment Delivery - The Basic Treatment Equivalent (B.T.E.)". Awarded by:University of New South Wales. SWSAHS Clinical School, 2001. http://handle.unsw.edu.au/1959.4/33381.

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The measurement of productivity in health care is difficult. Studies in various specialty disciplines of medicine have identified that the variation in complexities (casemix) between departments or hospitals will vary and therefore will affect any basic productivity statistics that are produced. Radiation oncology is a discipline of medicine where no such studies into radiotherapy casemix variations and the effect that these may have on productivity measures have been performed, despite the high capital expenditure involved in the delivery of radiotherapy. Radiation oncology productivity on linear accelerators is currently measured by the number of patients treated or number of treatment fields treated per unit time (usually per hour). These statistics have been collected for many years and productivity assessments were made on the variations in these statistics that exist between departments. However, these statistics do not consider the variations in casemix that occur between departments. These complexity differences may be quite marked and therefore may strongly influence the ability of a department to achieve a high patient or treatment field throughput. This may be seen as 'reduced productivity' with no consideration of the complexity of the caseload seen in the department. In addition, future technological changes that improve patient outcome may be introduced. These changes may make treatment more complex. Using older measures of productivity such as fields per hour or patients per hour will not consider these technological changes and the subsequent changes in complexity and hence departments may be seen as less productive in the future using current methods of analysis unless a more valid measure of productivity that considers complexity variations is introduced. There have only been 3 previous attempts at developing measures of linear accelerator productivity. Each of these models have been developed empirically and have not been clinically validated. No previous attempts have been made in determining a scientifically-derived complexity model that considers the variations in treatment technique. This thesis describes research performed between 1995 and 2001. This research study???s primary aims were to study the factors that affect radiotherapy treatment time and treatment complexity and to develop a model of linear accelerator productivity that does consider complexity variations in radiotherapy treatment delivery. This model is called the Basic Treatment Equivalent (B.T.E.). This series of trials examines the old models of linear accelerator productivity, describes the derivation and validation of the BTE model both in Australasia and the United Kingdom, identifies the factors that contribute to treatment time and treatment complexity, describes the development of a pilot model of productivity of gynaecological brachytherapy and outpatient chemotherapy using similar BTE methodology, discusses the potential uses of the BTE model, recent independent reviews of BTE by other groups, and the advantages and disadvantages of using such a model. This research has shown that it is possible to identify the various factors that contribute to treatment time and treatment complexity and to derive a model of linear accelerator productivity that considers the variations in complexity. The BTE model has been clinically validated in Australia, New Zealand and a couple of departments in the United Kingdom and Canada and has been adopted as a new measure by various groups. It requires regular updating to maintain currency particularly as there are frequent improvements in radiation treatment technology. Future studies should identify the differences these technological enhancements make to productivity. The BTE derived from outpatient chemotherapy delivery and gynaecological brachytherapy delivery shows promise although these models require further research with the assistance of other departments.

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Satory, Philip Reynard. "An Investigation into EPID Flood Fields Independent from the Linear Accelerator Beam". Thesis, University of Canterbury. Physics and Astronomy, 2008. http://hdl.handle.net/10092/2185.

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The EPID (electronic portal imaging device) was designed for in vivo imaging of patients during radiotherapy treatment. The ability of EPIDs to promptly acquire two dimensional data, lends them to be considered for use in quality assurance of the linac. This thesis set out to investigate the possibility of using a radionuclide, technetium 99 m (Tc99m), to produce a flood field for the calibration of an EPID, because using a beam calibrated EPID to measure the beam is self-referential. The difference in relative response between the energy spectrum of a 6MV beam and the Tc99m was investigated using EGSNRC DoseXYZ Monte Carlo Modelling. The relative output ratio was calculated to be less than 1.6%. The dose response of the EPID with respect to dose rate was checked using different activities of Tc99m and found to be linear. The flatness from a phantom was calculated, with a model in MATLAB, for a range of heights, overlaps, thickness, and deformations, to find the optimum balances between signal strength and flatness. This model was checked for accuracy using diagnostic radiographic film. The culmination of the energy response, linearity and the calculated flatness is a flood field taken with a flood phantom on the EPID with low signal strength. To get a signal to noise ratio of 3% the mean of over 2000 flood field images were used. This accuracy was not adequate for clinical use but the averaging of pixels it is accurate enough for QA.

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Cashmore, Jason. "Operation, characterisation & physical modelling of unflattened medical linear accelerator beams and their application to radiotherapy treatment planning". Thesis, University of Birmingham, 2013. http://etheses.bham.ac.uk//id/eprint/4616/.

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The flattening filter is a conical shaped piece of metal sitting within the treatment head of a linear accelerator, used to produce a flat, uniform beam of X-rays from the forward-peaked distribution exiting the target. Despite their routine use since the introduction of the linac in the 1950’s, however, there are still several unresolved issues surrounding their use. The photon scatter and electron contamination introduced by modifying the fluence are difficult to model, as is the variation in energy spectrum caused by differential absorption across the field. Leakage radiation also causes increased whole body doses to the patient, and the filter itself causes acts as an amplifier for beam bending and steering issues. With advances in tumour imaging, dose optimisation and in-room image-guidance it is now possible to locate a tumour accurately in space and to design radiation fields to conform to its shape, avoiding adjacent normal and critical tissues. This active production of non-flat fields means that the prerequisite for flat fields no longer exists, and the filter is potentially no longer a necessary component. This thesis reports on research to produce a filter-free linear accelerator, from basic operation and optimisation, dosimetric characterisation and beam modelling, through to treatment planning and dose delivery. FFF beams have been shown reduce many of the problems seen with the current generation of linear accelerators, producing beams that are inherently more stable, simple to model and with reduced patient leakage (leading to reduced secondary cancers). The increase in dose rate also translates into shorter treatment times for many treatments, aiding patient comfort and reducing problems associated with intra-fraction motion.

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Horne, Christopher Douglas. "Design and analysis of linear induction accelerators". Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309929.

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Crossman, John S. P. "Microdosimetry of photoneutrons around medical linear accelerators". Thesis, University of St Andrews, 1997. http://hdl.handle.net/10023/13366.

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Photoneutrons produced in the vicinity of medical linear accelerators for therapy, constitute a hazard which is difficult to assess and monitor. The aims of the project were to develop new techniques, using microdosimetry, which would be suitable for the improved quality control of pulsed photon beams and for the assessment of the associated photoneutron hazard in typical treatment facilities from the perspective of the patients and staff. The measurements of photoneutron yields and equivalent doses were obtained using activation analysis detectors around a 10 MV LINAC. To obtain adequate statistical precision, an optimum thickness of 2.5 cm of polyethylene was used that doubled the detector's sensitivity. This enabled the yields and spatial distribution of the low intensity field to be recorded. Photoneutron equivalent dose-rates of up to 0.104 Sv.h-1, or 0.1% of the useful photon dose- rates, were measured. In the literature, however, it was found that equivalent dose-rates could reach as high as 1 % of the useful photon treatment dose-rate for machines operating at X ray energies of ≥18 MV. Thus it is recommended that to uphold the principle of ALARA, such high energies (≥18 MV) should only be used when no lower energy machine is available. Microdosimetry with a tissue equivalent proportional counter (TEPC) microdosimeter, enabled the photoneutron contribution to the quality spectrum to be identified in the maze to the treatment room of the 10 MV LIN AC, and the photoneutrons there were assigned a radiation weighting factor of 20. The known problems concerning the rf interference and very high pulsed dose-rates inside the treatment room proved too severe to obtain meaningful results with the TEPC. The microdosimeter did however provide useful diagnostic information. Furthermore, a novel calibration technique for TEPC's was developed and an established one, the proton-edge method, was improved. A new approach was adopted to conduct microdosimetry in the vicinity of medical accelerators. This involved the design of a condensed phase microdosimeter comprising, a miniature CsI(T1) scintillator coupled to an optical fibre 20 m long, for conducting in-beam, on-line measurements of quality spectra. However, Cerenkov light and scintillation light produced in the optical fibre by the radiation fields was the cause of strong interference that has yet to be overcome. The application of the microdosimeter, which is still under development, to brachytherapy is proposed for in-vivo measurements.

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Plostinar, Ciprian. "Design principles for high power linear accelerators". Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:c425c3c8-772c-49a0-8764-257ae6af5bd6.

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The demand for high power proton beams is at an all time high. The global community has identified many applications ranging from spallation sources, material irradiation facilities and secondary beams factories to accelerator driven systems for energy production, transmutation of waste or production of tritium. The typical path to high power beams involves the use of a linac at least in the lower energy stages. For high intensity, high power operation, significant developments are needed particularly in the linac section and the front end of the machine. Consequently, this thesis brings original contributions in tackling several limiting aspects to do with two major pillars of high power operation in linacs: energy and intensity. One of the major decisions in any linac design concerns the choice of normal accelerating structures. The general aim of every designer is to find the optimal path to the final energy without compromising the beam quality or increasing excessively the structure complexity. In the absence of a much needed comparative assessment of accelerating cavities, this choice was often made based on available local expertise rather than solid reasoning. This problem is tackled at length in two chapters of this thesis in which a framework is created for a methodical examination of available structures. The result is the first systematic analysis of normal conducting structures for proton acceleration which includes beam dynamics, electromagnetic, mechanical, thermal and vacuum aspects of cavity design. On the intensity side, several innovative developments have arisen through involvement in the Front End Test Stand Project (FETS) and the ISIS linac upgrade efforts. Beam dynamics studies for the Medium Energy Beam Transport line (MEBT) of FETS, as well as an analysis of several other MEBT designs for existing international projects, highlighted the difficulty in reducing beam loss and emittance growth in high current MEBT lines incorporating beam choppers. Through end-to-end tracking studies, it was shown that the initial beam quality produced in the MEBT will heavily influence the emittance evolution, halo development and beam loss in subsequent structures. As a result, a novel distributed MEBT design is proposed as an alternative, allowing better matching and chopping as well as higher intensity, lossless operation. Further downstream, the beam quality is not only affected by initial mismatch and MEBT beam quality, but by the choice of operating points as well. Theoretical work developed over the last two decades indicate that safe tunes outside conventional equipartitioning limits can be found, but the lack of experimental verification remains a problem. This problem was tackled through an experimental campaign at J-PARC, where for the first time emittance exchange driven by the kz/kt = 2 resonance was measured in a linac with emittance ratios close to 1. Finally, these principles are applied to the design of a future upgrade of the ISIS linac. Three linac options have been developed accelerating the beam to 100, 180 and 800 MeV opening the possibility of MW-level operation in ISIS.

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Wang, Yi Zhen 1965. "Photoneutrons and induced activity from medical linear accelerators". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81453.

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This study involves the measurement of the neutron equivalent dose ( NED) and the induced activity produced from medical linear accelerators. For the NED, various parameters such as the profile, field effects and energy responses were studied. The NED in a Solid Water(TM) phantom was measured and a new quantity, the neutron equivalent dose tissue-air ratio (NTAR), was defined and determined. Neutron production for electron beams was also measured. For the induced activity, comparisons were carried out between different linacs, fields and dose rates. The half life and activation saturation were also studied. A mathematical model of induced activity was developed to explain the experimental results. Room surveys of NED and induced activity were performed in and around a high energy linear accelerator room. Unwanted doses from photoneutrons and induced activity to the high energy linear accelerator radiotherapy staff and patient were estimated.

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Taheri, Faissal Bakkali. "Numerical and experimental studies of coherent Smith-Purcell radiation". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:d483c501-ba46-4e08-9d38-5af29211aedc.

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This thesis investigates the properties of coherent Smith-Purcell radiation (cSPr) at femtosecond-scale in the case of electrons bunches in the ultrarelativistic regimes. Of particular interest is the use of cSPR as a diagnostic tool to determine the longitudinal time profiles of such bunches, the study of azimuthal distribution of the radiated energy, and a contribution to the understanding of polarization properties. The study consists in a first theoretical part carried mostly in the context of the surface-current theory, supported with insights from particle-in-cell simulations. Then, as a step toward a better determination of time profile, the question of phase reconstruction is addressed through the design of a new algorithm proposed in this thesis and tested in known challenging cases. Experimental results are then presented, spanning shifts having taken place at the FACET facility at SLAC, Stanford, between 2013 and 2015.

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Rodríguez, Castillo Miguel Lázaro. "Automation of the Monte Carlo simulation of medical linear accelerators". Doctoral thesis, Universitat Politècnica de Catalunya, 2016. http://hdl.handle.net/10803/392626.

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The main result of this thesis is a software system, called PRIMO, which simulates clinical linear accelerators and the subsequent dose distributions using the Monte Carlo method. PRIMO has the following features: (i) it is self- contained, that is, it does not require additional software libraries or coding; (ii) it includes a geometry library with most Varian and Elekta linacs; (iii) it is based on the general-purpose Monte Carlo code PENELOPE; (iv) it provides a suite of variance-reduction techniques and distributed parallel computing to enhance the simulation efficiency; (v) it is graphical user interfaced; and (vi) it is freely distributed through the website http://www.primoproject.net In order to endow PRIMO with these features the following tasks were conducted: - PRIMO was conceived with a layered structure. The topmost layer, named the GLASS, was developed in this thesis. The GLASS implements the GUI, drives all the functions of the system and performs the analysis of results. Lower layers generate geometry files, provide input data and execute the Monte Carlo simulation. - The geometry of Elekta linacs from series SU and MLCi were coded in the PRIMO system. - A geometrical model of the Varian True Beam linear accelerator was developed and validated. This model was created to surmount the limitations of the Varian distributed phase-space files and the absence of released information about the actual geometry of that machine. This geometry model was incorporated into PRIMO. - Two new variance-reduction techniques, named splitting roulette and selective splitting, were developed and validated. In a test made with an Elekta linac it was found that when both techniques are used in conjunction the simulation efficiency improves by a factor of up to 45. - A method to automatically distribute the simulation among the available CPU cores of a computer was implemented. The following investigations were done using PRIMO as a research tool : - The configu ration of the condensed history transport algorithm for charged particles in PENELOPE was optimized for linac simulation. Dose distributions in the patient were found to be particularly sensitive to the values of the transport parameters in the linac target. Use of inadequate values of these parameters may lead to an incorrect determination of the initial beam configuration or to biased dose distributions. - PRIMO was used to simulate phase-space files distributed by Varian for the True Beam linac. The results were compared with experimental data provided by five European radiotherapycenters. It was concluded thatthe latent variance and the accuracy of the phase-space files were adequate for the routine clinical practice. However, for research purposes where low statistical uncertainties are required the phase-space files are not large enough. To the best of our knowledge PRIMO is the only fully Monte Carlo-based linac and dose simulation system , addressed to research and dose verification, that does not require coding tasks from end users and is publicly available.
El principal resultado de esta tesis es un sistema informático llamado PRIMO el cual simula aceleradores lineales médicos y las subsecuentes distribuciones de dosis empleando el método de Monte Carlo. PRIMO tiene las siguiente características: (i) es auto contenido, o sea no requiere de librerías de código ni de programación adicional ; (ii) incluye las geometrías de los principales modelos de aceleradores Varían y Elekta; (iii) está basado en el código Monte Carlo de propósitos generales PENELOPE; (iv) contiene un conjunto de técnicas de reducción de varianza y computación paralela distribuida para mejorar la eficiencia de simulación; (v) tiene una interfaz gráfica de usuario; y (vi) se distribuye gratis en el sitio web http://vvww.primoproject.net. Para dotar a PRIMO de esas características, se realizaron las tareas siguientes: - PRIMO se concibió con una estructura de capas. La capa superior, nombrada GLASS, fue desarrollada en esta tesis. GLASS implementa la interfazgráfica de usuario, controla todas las funciones del sistema y realiza el análisis de resultados. Las capas inferiores generan los archivos de geometría y otros datos de entrada y ejecutan la simulación Monte Carlo. - Se codificó en el sistema PRIMO la geometría de los aceleradores Elekta de las series SLi y MLC. - Se desarrolló y validó un modelo geométrico del acelerador TrueBeam de Varian. Este modelo fue creado para superar las limitaciones de los archivos de espacio de fase distribuidos por Varian, así como la ausencia de información sobre la geometría real de esta máquina. Este modelo geométrico fue incorporado en PRIMO. - Fueron desarrolladas y validadas dos nuevas técnicas de reducción de varianza nombradas splitting roulette y selective splitting. En pruebas hechas en un acelerador Elekta se encontró que cuando ambas técnicas se usan en combinación, la eficiencia de simulación mejora 45 veces. - Se implementó un método para distribuir la simulación entre los procesadores disponibles en un ordenador. Las siguientes investigaciones fueron realizadas usando PRIMO como herramienta: - Fue optimizada la configuración del algoritmo de PENELOPE para el transporte de partículas cargadas con historia condensada en la simulación del linac. Se encontró que las distribuciones de dosis en el paciente son particularmente sensibles a los valores de los parámetros de transporte usados para el target del linac. El uso de va lores inadecuados para esos parámetros puede conducir a una incorrecta determinación de la configuración del haz inicial o producir sesgos en las distribuciones de dosis. - Se utilizó PRIMO para simular archivos de espacios de fase distribuidos por Varian para el linac TrueBeam. Los resultados se compararon con datos experimentales aportados por cinco centros de radioterapia europeos. Se concluyó que la varianza latente y la exactitud de estos espacios de fase son adecuadas para la práctica clínica de rutina. Sin embargo estos espacios de fase no son suficientemente grandes para emplearse en investigaciones que requieren alcanzar una baja incertidumbre estadística. Hasta donde conocemos, PRIMO es el único sistema Monte Carlo que simula completamente el acelerador lineal y calcula la dosis absorbida, dirigido a la investigación y la verificación de dosis que no requiere del usuario tareas de codificación y está disponible públicamente

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Più fonti

Libri sul tema "Linear accelerators in medicine"

C, Williams P., a cura di. Linear accelerators for radiation therapy. 2^a ed. Bristol, UK: Institute of Physics Pub., 1997.

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Linear accelerators for radiation therapy. Bristol: Hilger in collaboration with the Hospital Physicists' Association, 1986.

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1937-, Wangler Thomas P., a cura di. RF linear accelerators. 2^a ed. Weinheim: Wiley-VCH, 2008.

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Tomas, Kron, Hoban Peter e Metcalfe Peter, a cura di. The physics of radiotherapy x-rays and electrons / by Peter Metcalfe, Tomas Kron, and Peter Hoban. Madison, Wis: Medical Physics Pub., 2007.

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Wangler, Thomas P. Principles RF Linear Accelerators. Weinheim, Germany: Wiley-VCH Verlag GmbH, 1998. http://dx.doi.org/10.1002/9783527618408.

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Theory of resonance linear accelerators. Chur, Switzerland: Harwood, 1985.

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Wangler, Thomas P. Principles of RF linear accelerators. New York: Wiley, 1998.

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Oguri, Y. Schottky Noise Analysis in Linear Accelerators. Darmstadt: Gesellschaft fur Schwerionenforschung, 1988.

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Kato, Takao. Improvement of the laser-based alignment system for the J-PARC proton linac. Tsukuba-shi, Ibaraki-ken, Japan: High Energy Accelerator Research Organization, 2005.

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Kudri︠a︡vt︠s︡ev, A. M. Obʺedinennai︠a︡ USA-CERN-Japan uskoritelʹnai︠a︡ shkola--VCh tekhnika dli︠a︡ uskoriteleĭ, 9-18 se[n]ti︠a︡bri︠a︡ 1996 g., I︠A︡ponii︠a︡: Lekt︠s︡ii, prochitannye sotrudnikami II︠A︡F SO RAN. Novosibirsk: In-t i︠a︡dernoĭ fiziki im. G.I. Budkera SO RAN, 1997.

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Capitoli di libri sul tema "Linear accelerators in medicine"

Wiedemann, Helmut. "Linear Accelerators". In Particle Accelerator Physics I, 25–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 1999. http://dx.doi.org/10.1007/978-3-662-03827-7_2.

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Wiedemann, Helmut. "Linear Accelerators". In Particle Accelerator Physics, 25–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-662-05034-7_2.

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Wiedemann, Helmut. "Linear Accelerators". In Particle Accelerator Physics, 25–52. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/978-3-662-02903-9_2.

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Wiedemann, Helmut. "Linear Accelerators". In Graduate Texts in Physics, 43–57. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-18317-6_2.

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Ueyama, Takahiro, e Christophe Lécuyer. "Building Science-based Medicine at Stanford: Henry Kaplan and the Medical Linear Accelerator, 1948–1975". In Devices and Designs, 137–55. London: Palgrave Macmillan UK, 2006. http://dx.doi.org/10.1057/9780230286405_8.

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Smith, T. I. "Superconducting Linear Accelerators". In Advances in Cryogenic Engineering, 102–8. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4757-0516-4_12.

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Guerrieri, Patrizia, Paolo Montemaggi, Volker Budach, Carmen Stromberger, Volker Budach, Volker Budach, Anthony E. Dragun et al. "Linear Accelerators (LINAC)". In Encyclopedia of Radiation Oncology, 437–50. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-540-85516-3_37.

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Porter, Hamish. "Traditional Linear Accelerators". In Handbook of Radiotherapy Physics, Vol1:173—Vol1:256. 2^a ed. Boca Raton: CRC Press, 2021. http://dx.doi.org/10.1201/9780429201493-14.

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Westenskow*, Glen, e Yu-Jiuan Chen. "Applications of Electron Linear Induction Accelerators". In Induction Accelerators, 165–83. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-13917-8_8.

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Prestwich, K. R. "Radial Transmission-Line Linear Accelerators". In High-Brightness Accelerators, 473–96. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4684-5508-3_19.

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Atti di convegni sul tema "Linear accelerators in medicine"

Sidorin, A., Carlos Granja, Claude Leroy e Ivan Stekl. "Linear Accelerators". In Nuclear Physics Medthods and Accelerators in Biology and Medicine. AIP, 2007. http://dx.doi.org/10.1063/1.2825831.

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Sidorin, Anatoly, Carlos Granja e Claude Leroy. "Linear Accelerators". In NUCLEAR PHYSICS METHODS AND ACCELERATORS IN BIOLOGY AND MEDICINE: Fifth International Summer School on Nuclear Physics Methods and Accelerators in Biology and Medicine. AIP, 2010. http://dx.doi.org/10.1063/1.3295681.

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Juste, B., R. Miro, G. Verdu, S. Diez e J. M. Campayo. "Neutron activation processes simulation in an Elekta medical linear accelerator head". In 2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2014. http://dx.doi.org/10.1109/embc.2014.6944260.

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Firmansyah, A. F., O. A. Firmansyah e W. E. Wibowo. "Preliminary study of Varian Halcyon linear accelerator machine performance with 6 MV FFF photon beam". In PROCEEDINGS OF THE INTERNATIONAL CONFERENCE AND SCHOOL ON PHYSICS IN MEDICINE AND BIOSYSTEM (ICSPMB): Physics Contribution in Medicine and Biomedical Applications. AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0048159.

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Morato, S., B. Juste, R. Miro, G. Verdu e S. Diez. "Experimental validation of neutron activation simulation of a varian medical linear accelerator". In 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE, 2016. http://dx.doi.org/10.1109/embc.2016.7592010.

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Azzi, A., S. A. Pawiro e T. Mart. "3D dose reconstruction of 6 MV medical linear accelerator based on modified ray tracing algorithm: A preliminary result". In PROCEEDINGS OF THE INTERNATIONAL CONFERENCE AND SCHOOL ON PHYSICS IN MEDICINE AND BIOSYSTEM (ICSPMB): Physics Contribution in Medicine and Biomedical Applications. AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0047744.

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"Assessment of using Monte Carlo methods in studies related to neutron contamination of radiotherapy in linear accelerator: A comparative review". In International Conference on Medicine, Public Health and Biological Sciences. CASRP Publishing Company, Ltd. Uk, 2016. http://dx.doi.org/10.18869/mphbs.2016.174.

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Straight, R. C. "Biomedical Applications of Free Electron Laser in the Ultraviolet". In Free-Electron Laser Applications in the Ultraviolet. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/fel.1988.fc5.

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Abstract (sommario):

Free electron lasers (FED are high-power, pulse periodic lasers with wide range wavelength tunability that have important and unique potential applications in photobiology and medicine. The FEL technology most appropriate for biomedical studies/applications in the IR-VIS range is the technology based on the radio frequency (RF)-linear accelerator (LINAC)-hybrid magnetic undulator (wiggler) or RF-LINAC-wiggler technology and optical cavity (1,2). Storage rings (3) and LINACs with photocathode injectors are promising technology for obtaining UV-FEL radiation. Initial studies are in progress using the IR technology: (a) to develop optical systems and fibers for biological studies in the mid-IR (2-5 μm) range; (b) to obtain visible and ultraviolet (uv) wavelengths using FEL harmonics and non-linear crystals; and (c) to study photobiodisruptive processes, determine light-tissue interaction thresholds, tissue damage zones, and photobiochemical processes for clinically relevant biological applications. The MARK III (Stanford Photon Research Laboratory) FEL operating as a tunable laser in the wavelength range 2.0 μm -5.0 μm at 0.1 mJ to 60 mJ per macropulse (tMP - 1.5 μs) and 15 Hz is being used for the initial IR-VIS studies. This paper considers the potential diagnostic, therapeutic and surgical applications of UV-FEL radiation (190 nm - 390 nm) in biomedicine.

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Birx, Daniel. "Induction linear accelerators". In The Physics of Particles Accelerators: Based in Part on the U.S. Particle Accelerator School (USPAS) Seminars and Courses in 1989 and 1990. AIP, 1992. http://dx.doi.org/10.1063/1.41961.

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AMALDI, UGO. "ACCELERATORS AND MEDICINE". In Proceedings of the Joint US–CERN–Japan–Russia School on Particle Accelerators. WORLD SCIENTIFIC, 1999. http://dx.doi.org/10.1142/9789812818003_0020.

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Rapporti di organizzazioni sul tema "Linear accelerators in medicine"

Alvarez, Luis W. History of Proton Linear Accelerators. Office of Scientific and Technical Information (OSTI), gennaio 1987. http://dx.doi.org/10.2172/891327.

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Whittum, David H. Introduction to Microwave Linear [Accelerators]. Office of Scientific and Technical Information (OSTI), gennaio 1999. http://dx.doi.org/10.2172/9980.

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Nantista, C. Radio-Frequency Pulse Compression for Linear Accelerators. Office of Scientific and Technical Information (OSTI), giugno 2018. http://dx.doi.org/10.2172/1454129.

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Senichev, Yu. Transient effect in high intensity proton linear accelerators. Office of Scientific and Technical Information (OSTI), settembre 1993. http://dx.doi.org/10.2172/67475.

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Ross, Marc. Review of Diagnostics for Next Generation Linear Accelerators. Office of Scientific and Technical Information (OSTI), maggio 2001. http://dx.doi.org/10.2172/784919.

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Lapostolle, P. M. Proton linear accelerators: A theoretical and historical introduction. Office of Scientific and Technical Information (OSTI), luglio 1989. http://dx.doi.org/10.2172/6038195.

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Kelly, Maeve Emma. Comparison of MCNP Variance Reduction Techniques for Linear Accelerators. Office of Scientific and Technical Information (OSTI), agosto 2019. http://dx.doi.org/10.2172/1558942.

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Ekdahl, Carl August Jr. Optimum tunes for the DARHT and Scorpius linear induction accelerators. Office of Scientific and Technical Information (OSTI), marzo 2019. http://dx.doi.org/10.2172/1499288.

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Raubenheimer, Tor O. Estimates of Emittance Dilution and Stability in High-Energy Linear Accelerators. Office of Scientific and Technical Information (OSTI), novembre 2000. http://dx.doi.org/10.2172/784748.

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Haj, Tahar M., e F. Meot. Transverse beam dynamics in non-linear Fixed Field Alternating Gradient accelerators. Office of Scientific and Technical Information (OSTI), marzo 2016. http://dx.doi.org/10.2172/1244213.

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