Dissertations / Theses on the topic 'Radiotherapy quality assurance'
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Sandberg, Linnea. "Quality assurance of a radiotherapy registry." Thesis, Umeå universitet, Institutionen för fysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-176779.
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The radiotherapy clinics in Sweden have been without a functioning national platform consisting of dose data from patients undergoing radiotherapy. A national collaboration between clinics will improve the quality of radiotherapy since clinics will be able to compare dose data from treatment plans between clinics. It will also help and improve future researches in radiotherapy. A new national quality registry for radiotherapy in Sweden is under development and is located on the INCA platform. The aim of this study is to do a quality assurance of the INCA registry. The data stored in the registry are calculated from the treatment plans stored locally at the clinics. The quality assurance of the registry is done by creating a program run by Python code and by using Streamlit as the graphical user interface. The program takes dose and volume data from the dose volume histograms located in treatment plans from the INCA database and compares it with the dose and volume data from the local clinics' treatment planning system. The different treatment planning systems considered in the program are Oncentra(Elekta, Sweden), Eclipse(Varian, U.S.), RayStation(RaySearch Laboratories, Sweden) and Monaco(Electa, Sweden). The compared absorbed doses are the dose to 99% of the structure volume(D99%), D98%, D50%, D2% and D1%. The program generates how much the INCA data differs from the TPS data in percent and is named QARS(Quality Assurance of the Radiotherapy Database in Sweden). A verification of the created program and a preliminary evaluation is done on a limited dataset containing three patient groups(prostate patients, lung patients and head and neck patients) with five patients in each group. The dataset is run through the program with patient data from both Oncentra and Eclipse. The result indicates that all the near-maximum doses, D2% and D1% in INCA are very close to their corresponding TPS dose. There is a more noticeable difference in the near-minimum doses, D99% and D98% but also for some D50% where the difference seems to increase in larger structure volumes with very low doses and in very small structure volumes, smaller than 0.01 cm3. It is compared how well INCA agrees with Oncentra and Eclipse respectively and it is clear that Eclipse has a smaller difference to INCA than Oncentra for structures with very small volumes and larger structures with low doses. To summarise the study, it generates a program for quality assurance of the national quality registry for radiotherapy in Sweden which hopefully can help improve the quality of radiotherapy and help future researches in the field.
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Binny, Diana. "Radiotherapy quality assurance using statistical process control." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/130738/1/Diana_Binny_Thesis.pdf.
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The work presented in this thesis was a step forward in applying statistics to the important problem of monitoring machine performance and quantifying optimal treatment quality assurance in radiotherapy. This research investigated the use of an analytical decision making tool known as Statistical Process Control (SPC) that employs statistical means to measure, monitor and identify random and systematic errors in a process based on observed behaviour. In this research, several treatment machine and planning system parameters were investigated and a method of calculating SPC based tolerances to achieve optimal treatment goals was highlighted in this study.
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Adjeiwaah, Mary. "Quality assurance for magnetic resonance imaging (MRI) in radiotherapy." Licentiate thesis, Umeå universitet, Institutionen för strålningsvetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-142603.
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Magnetic resonance imaging (MRI) utilizes the magnetic properties of tissues to generate image-forming signals. MRI has exquisite soft-tissue contrast and since tumors are mainly soft-tissues, it offers improved delineation of the target volume and nearby organs at risk. The proposed Magnetic Resonance-only Radiotherapy (MR-only RT) work flow allows for the use of MRI as the sole imaging modality in the radiotherapy (RT) treatment planning of cancer. There are, however, issues with geometric distortions inherent with MR image acquisition processes. These distortions result from imperfections in the main magnetic field, nonlinear gradients, as well as field disturbances introduced by the imaged object. In this thesis, we quantified the effect of system related and patient-induced susceptibility geometric distortions on dose distributions for prostate as well as head and neck cancers. Methods to mitigate these distortions were also studied. In Study I, mean worst system related residual distortions of 3.19, 2.52 and 2.08 mm at bandwidths (BW) of 122, 244 and 488 Hz/pixel up to a radial distance of 25 cm from a 3T PET/MR scanner was measured with a large field of view (FoV) phantom. Subsequently, we estimated maximum shifts of 5.8, 2.9 and 1.5 mm due to patient-induced susceptibility distortions. VMAT-optimized treatment plans initially performed on distorted CT (dCT) images and recalculated on real CT datasets resulted in a dose difference of less than 0.5%. The magnetic susceptibility differences at tissue-metallic,-air and -bone interfaces result in local B0 magnetic field inhomogeneities. The distortion shifts caused by these field inhomogeneities can be reduced by shimming. Study II aimed to investigate the use of shimming to improve the homogeneity of local B0 magnetic field which will be beneficial for radiotherapy applications. A shimming simulation based on spherical harmonics modeling was developed. The spinal cord, an organ at risk is surrounded by bone and in close proximity to the lungs may have high susceptibility differences. In this region, mean pixel shifts caused by local B0 field inhomogeneities were reduced from 3.47±1.22 mm to 1.35±0.44 mm and 0.99±0.30 mm using first and second order shimming respectively. This was for a bandwidth of 122 Hz/pixel and an in-plane voxel size of 1×1 mm2. Also examined in Study II as in Study I was the dosimetric effect of geometric distortions on 21 Head and Neck cancer treatment plans. The dose difference in D50 at the PTV between distorted CT and real CT plans was less than 1.0%. In conclusion, the effect of MR geometric distortions on dose plans was small. Generally, we found patient-induced susceptibility distortions were larger compared with residual system distortions at all delineated structures except the external contour. This information will be relevant when setting margins for treatment volumes and organs at risk. The current practice of characterizing MR geometric distortions utilizing spatial accuracy phantoms alone may not be enough for an MR-only radiotherapy workflow. Therefore, measures to mitigate patient-induced susceptibility effects in clinical practice such as patient-specific correction algorithms are needed to complement existing distortion reduction methods such as high acquisition bandwidth and shimming.
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Hack, Joshua. "Development and implementation of quality-assurance standards for external beam intensity modulated radiation therapy." Toledo, Ohio : University of Toledo, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=mco1265034762.
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Liu, Guilin. "The application of electronic portal imaging devices to radiotherapy quality assurance /." Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phl7833.pdf.
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Aland, Trent J. "Quality assurance of complex radiotherapy treatments using high-resolution 2D dosimeters." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/228242/1/Trent_Aland_Thesis.pdf.
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The study investigates various components of the quality assurance (QA) processes for complex modern day radiotherapy treatments with a focus on the use of high resolution 2D dosimeters. Pre-treatment QA using a rotating 2D array on an O-ring linac, the use of radiochromic film for in-vivo dosimetry, a novel smartphone dosimetry system, a novel technique to increase fiducial visualisation during MV based intra-fraction monitoring, and use of Varian Portal Dosimetry to detect inter-fraction anatomical changes were all investigated and are discussed.
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Tang, Nin-fai Francis, and 鄧年輝. "Monte Carlo dose calculations in quality assurance for IMRT of head and neck cancers." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40203797.
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PASSARO, BRUNO M. "Análise quantitativa dos resultado dos testes de controle de qualidade em radioterapia." reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10038.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Bose, Rajiv. "The development of an in-vivo dosimeter for the application in radiotherapy." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/7173.
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The expectation for continual improvements in the treatment of cancer has brought quality assurance in radiotherapy under scrutiny in recent years. After a cancer diagnosis a custom treatment plan is devised to meet the particular needs of the patient's condition based on their prognosis. A cancer treatment plan will typically comprise of several cancer treatment technologies combining to form a comprehensive programme to fight the malignant growth. Inherent in each cancer treatment technology is a percentage error in treatment accuracy. Quality assurance is the medical practice to minimise the percentage error in treatment accuracy. Radiotherapy is one of the several cancer treatment technologies a patient might receive as part of their treatment plan, and in-vivo dosimetry is a quality assurance technology specifically designed to minimise the percentage error in the treatment accuracy of radiotherapy. This thesis outlines the work completed in the design of a next generation dosimeter for in-vivo dosimetry. The proposed dosimeter is intended to modernise the process of measuring the absorbed dose of ionising radiation received by the target volume during a radiotherapy session. To accomplish this goal the new dosimeter will amalgamate specialist technologies from the field of particle physics and reapply them to the field of medical physics. This thesis describes the design of a new implantable in-vivo dosimeter, a dosimeter comprising of several individual stages of electronics working together to modernise quality assurance in radiotherapy. Presented within this thesis are the results demonstrating the performance of two critical stages for this new dosimeter, including: the oating gate metal oxide field effective transistor, a radiation sensitive electronic component measuring an absorbed dose of radiation; and the micro antenna, a highly specialist wireless communications device working to transmit a high frequency radio signal. This was a collaborative project between Rutherford Appleton Laboratory and Brunel University. The presented work in this thesis was completed between March 2007 and January 2011.
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SANTOS, GELSON P. dos. "Desenvolvimento de um sistema dosimetrico multidiodos para garantia da qualidade em equipamentos radioterapeuticos." reponame:Repositório Institucional do IPEN, 2002. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11065.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Nyholm, Tufve. "Verification of dose calculations in radiotherapy." Doctoral thesis, Umeå : Umeå University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1931.
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Illerstam, Fredrik. "Quality Assurance of the Spatial Accuracy of Large Field of View Magnetic Resonance Imaging." Thesis, KTH, Skolan för teknik och hälsa (STH), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-148815.
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In todays Radiotherapy Treatment Planning, RTP, it is common to use Computed Tomography, CT, together with Magnetic Resonance Imaging, MRI, where CT provides electron density information and a geometrical reference, and where MRI provides superior soft tissue contrast. To sim- plify the workflow and improve treatment accuracy, research groups have demonstrated how to exclude CT and use a MRI-only approach. In this thesis, a method for spatial distortion analysis, ultimately enabling quality assurance, QA, of the spatial accuracy of MRI, was defined, tested and evaluated. A phantom was built to cover the entire clinical Field Of View, FOV, and 6mm-diameter fluid filled paintball markers were placed in a well-defined geometrical pattern within the phantom, and used as positive contrast. The phantom was imaged with a 3D Fast Gradient Echo sequence and a 3D Fast Spin Echo sequence. The markers were identified in the image data by a MATLAB-algorithm, and the location of the center of mass was calculated for each marker and compared to a theoretical reference. The location error was defined as the spatial distortion - a measurement of the spatial accuracy. Imaging parameters were altered and the effect on the spatial accuracy was analyzed. The spatial distortions were successfully measured within the entire (maximal) clinical FOV. It was shown that high readout bandwidth reduced distortions in the frequency encoding direction. These distortions could thus be attributed to B0-inhomogeneities. It was also determined that increasing the readout bandwidth to the maximum value reduced the maximum distortions in the frequency encoding direction to the same level as the maximum distortions in the other two phase-encoding directions of the 3D acquisitions. The voxel size had a very small effect on the spatial accuracy, enabling large voxelsize to be used when imaging the phantom, to decrease the scan time. The method was deemed capable of serving as a basis for QA of the spatial accuracy of large FOV MRI, which is needed in future MRI-only RTP approaches.
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Celi, Sofia. "Contribution à la radiothérapie adaptative par analyse systématique de la fluence en entrée et de la dose en sortie du patient." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30037/document.
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La radiothérapie moderne combine les techniques complexes et les traitements personnalisés, avec le risque que certaines évolutions et erreurs ayant lieu au cours de traitement passent inaperçues. Ces aléas peuvent entraîner des conséquences graves pour la santé du patient. Dans cette perspective, nous avons étudié le potentiel d'un système de dosimétrie in vivo de transit pour le suivi continu du patient et, par conséquent, la radiothérapie adaptative. L'expérience clinique et des tests de faisabilité ont permis de définir les axes de travail principaux: l'automatisation et la simplification du procédé d'analyse des contrôles. Les développements incluent la création d'une bibliothèque de données standard et une série d'analyses de causes racines, permettant ainsi de renforcer la précision du système, d'améliorer l'automatisation de sa mise en place et d'identifier des pistes pour une analyse efficace des résultats et pour la création d'outils supplémentaires facilitant le suivi et l'adaptation du traitement en routine cliniqueModern radiation therapy combines complex techniques and personalized treatments, with the risk that certain evolutions and errors occurring during the course of the treatment might go unnoticed. These fluctuations may cause great damage to the health of the patient. In this perspective, we worked on the potential of a transit in vivo dosimetry system for continuous monitoring of the patient and, hereafter, adaptive radiotherapy. Our clinical experience and feasibility testing determined the main lines of work : automatization and simplification of the results analysis method. The developments included the creation of a golden data library and a series of root cause analyzes, allowing us to strengthen the accuracy of the system, to enhance the automatization of the setup and to identify tracks for an efficient analysis of the results and for the creation of additional analytical tools to facilitate the monitoring and adaptation of the treatments in clinical routine
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Djordjevic, Milos. "Evaluation of Geometric Accuracy and Image Quality of an On-Board Imager (OBI)." Thesis, Stockholm University, Medical Radiation Physics (together with KI), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6967.
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In this project several tests were performed to evaluate the performance of an On-Board Imager® (OBI) mounted on a clinical linear accelerator. The measurements were divided into three parts; geometric accuracy, image registration and couch shift accuracy, and image quality. A cube phantom containing a radiation opaque marker was used to study the agreement with treatment isocenter for both kV-images and cone-beam CT (CBCT) images. The long term stability was investigated by acquiring frontal and lateral kV images twice a week over a 3 month period. Stability in vertical and longitudinal robotic arm motion as well as the stability of the center-of-rotation was evaluated. Further, the agreement of kV image and CBCT center with MV image center was examined.
A marker seed phantom was used to evaluate and compare the three applications in image registration; 2D/2D, 2D/3D and 3D/3D. Image registration using kV-kV image sets were compared with MV MV and MV-kV image sets. Further, the accuracy in 2D/2D matches with images acquired at non-orthogonal gantry angles was evaluated. The image quality in CBCT images was evaluated using a Catphan® phantom. Hounsfield unit (HU) uniformity and linearity was compared with planning CT. HU accuracy is crucial for dose verification using CBCT data.
The geometric measurements showed good long term stability and accurate position reproducibility after robotic arm motions. A systematic error of about 1 mm in lateral direction of the kV-image center was detected. A small difference between kV and CBCT center was observed and related to a lateral kV detector offset. The vector disagreement between kV- and MV-image centers was 2 mm at some gantry angles. Image registration with the different match applications worked sufficiently. 2D/3D match was seen to correct more accurately than 2D/2D match for large translational and rotational shifts. CBCT images acquired with full-fan mode showed good HU uniformity but half fan images were less uniform. In the soft tissue region the HU agreement with planning CT was reasonable while a larger disagreement was observed at higher densities. This work shows that the OBI is robust and stable in its performance. With regular QC and calibrations the geometric precision of the OBI can be maintained within 1 mm of treatment isocenter.
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Sentker, Thilo [Verfasser], and Florian [Akademischer Betreuer] Grüner. "Feasibility and uncertainties of 4D dose simulation for post-treatment quality assurance in radiotherapy of moving targets / Thilo Sentker ; Betreuer: Florian Grüner." Hamburg : Staats- und Universitätsbibliothek Hamburg, 2020. http://d-nb.info/121218100X/34.
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Grevillot, Loïc. "Monte Carlo simulation of active scanning proton therapy system with Gate/Geant4 : Towards a better patient dose quality assurance." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00735746.
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Hadron Therapy is an advanced radiotherapy technique for cancer treatment. It offers a better irradiation ballistic than conventional techniques and therefore requires appropriate quality assurance procedures. In this work, we upgraded the GEANT4-based GATE Monte Carlo platform in order to recalculate the TPS dose distributions in view of further benchmarking. In a first step, we selected an appropriate simulation environment (physics models and parameters) in order to produce accurate and efficient simulations. GATE simulations were validated using measurements and other Monte Carlo codes for depth-dose and transverse profiles. While a good agreement was found for depth-dose profiles, larger discrepancies were pointed out for transverse profiles. In a second step, we developed a modeling method to simulate active scanning beam delivery systems, which does not require to simulate the components of the treatment nozzle. The method has been successfully applied to an IBA proton therapy system and validated against measurements for complex treatment plans. Interfaces have also been developed in order to link DICOM RT ION PLAN and DICOM RT DOSE with GATE. Finally, we compared in a third step the TPS and Monte Carlo dose distributions in homogeneous and heterogeneous configurations. The beam models of both dose engines were in satisfactory agreement, allowing further evaluation of clinical treatment plans. A two-field prostate plan has been evaluated, showing a satisfactory agreement between the TPS and Monte Carlo, and demonstrating the novel capabilities of the platform for the evaluation of the TPS. To summarize, we selected an appropriate simulation environment for proton therapy, proposed a modeling method for active scanning systems and presented a method to compare the TPS and Monte Carlo dose distributions. All tools developed in GATE were or will be publicly released. A detailed validation stage of the system including absolute dosimetry is still necessary, in order to quantitatively evaluate its accuracy in various homogeneous and heterogeneous configurations. In this thesis, we have demonstrated that the GATE Monte Carlo platform is a good candidate for the simulation of active scanning delivery systems, allowing further TPS benchmarking. Moreover, the GATE platform also handles imaging applications, such as PET or prompt-gamma imaging towards online treatment monitoring and paves the way of interdisciplinary research advances.
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Beaudry, Joel. "4D cone-beam CT image reconstruction of Varian TrueBeam v1.6 projection images for clinical quality assurance of stereotactic ablative radiotherapy to the lung." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52814.
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On-board cone-beam computed tomography (CBCT) imaging integrated with medical linear accelerators offers a viable tool for tumor localization just prior to radiation treatment delivery. However, the exact tumor location during treatment is not well-defined due to respiratory motion. This is taken into account during treatment planning by adding margins to the visible tumor volume defining the high dose region. The respiratory motion used to optimize the treatment plan is not guaranteed to be reproducible on the day of treatment, suggesting that the high dose region may not fully contain the tumor at all points of its trajectory during treatment. In this thesis, to image the tumor at the different portions of the breathing cycle, CBCT projections were binned by the respiratory signal at their time of acquisition. Reconstructing each bin created a 3D image depicting the tumor at one point of its trajectory. Combining the binned reconstructions added in a temporal component, defining a 4D-CBCT. 4D-CBCT reconstructions were performed on 6 stereotactic ablative radiotherapy (SABR) lung cancer patients. Imaging was performed using the Varian TrueBeam (v1.6) and respiratory information was captured with the infra-red camera-based Varian real-time position management
(RPM) system. Both analytical and iterative reconstruction algorithms, and image quality metrics were used for a comparative study. Tumor motion was measured by tracking the visible tumor volume centroid from each 4D-CBCT image. The high dose regions defined during treatment planning were compared to the 4D-CBCT tumor volume during its trajectory using an overlap metric to determine if the tumor remained confined to the treatment volume, or not.
4D-CBCTs were found to be well reconstructed using iterative methods. When viewed sequentially the 4D-CBCT images visibly show tumor motion following a sinusoidal-like behavior. Examination of the tumor motion and overlap metric verify that the margins currently used to define the high dose region fully encompass the tumor during all times of its trajectory, i.e 100% overlap within error. The results indicate the current margins used for SABR patients at the British Columbia Cancer Agency are sufficient in providing adequate tumor coverage
when accounting for tumor motion and setup uncertainties.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Passaro, Bruno Martins. "Análise quantitativa dos resultados dos testes de controle de qualidade em radioterapia." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-21112011-095001/.
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Os aceleradores lineares representam a mais importante, prática e versátil produtores de raios-X de alta energia em radioterapia. O comportamento funcional destes equipamentos pode variar devido a defeitos eletrônicos, falhas de componentes ou rupturas mecânicas, ou então podem variar devido ao deterioramento e envelhecimento de seus componentes. A manutenção da qualidade dos tratamentos depende essencialmente da estabilidade dos aceleradores e do controle de qualidade das instituições para monitorar desvios nos parâmetros do feixe. O objetivo deste trabalho consiste em avaliar e analisar a estabilidade do fator de calibração dos aceleradores lineares, bem como os demais parâmetros dosimétricos normalmente incluídos em um programa de controle de qualidade em radioterapia. A média dos fatores de calibração dos aceleradores para o período de aproximadamente quatro anos para os Clinacs 600C e 6EX foram (0,998 ± 0,012) e (0,996 ± 0,014), respectivamente. Para o Clinac 2100CD de 6 MV e 15 MV foi (1,008 ± 0,009) e (1,006 ± 0,010), respectivamente, em um período de aproximadamente quatro anos. Através de análises estatísticas nos três aceleradores lineares verificou-se que os coeficientes de variação dos fatores de calibração apresentaram valores inferiores a 2% o que mostra uma homogeneidade nos dados. Através do cálculo da distribuição normal dos fatores de calibração, verificou-se que para os Clinacs 600C e 2100CD, é esperada uma probabilidade de que em mais de 90% dos casos os valores estejam dentro dos limites aceitáveis segundo o protocolo TG-142, enquanto que para o Clinac 6EX é esperado em torno de 85% uma vez que esse acelerador apresentou diversas trocas de componentes. Os valores do TPR20,10 dos três aceleradores são praticamente constantes e dentro dos limites aceitáveis segundo o protocolo TG-142. Pode-se concluir que um estudo detalhado dos dados do fator de calibração dos aceleradores e do TPR20,10 a partir de um ponto de vista quantitativo, é extremamente útil em um programa de garantia de qualidade.The linear accelerators represent the most important, practical and versatile source of ionizing radiation in radiotherapy. These functional characteristics influence the geometric and dosimetric accuracy of therapeutic doses applied to patients. The performance of this equipment may vary due to electronic defects, component failures or mechanical breakdowns, or may vary due to the deterioration and aging of components. Maintaining the quality of care depends on the stability of the accelerators and quality control of the institutions to monitor deviations in the parameters of the beam. The aim of this study is to assess and analyze the stability of the calibration factor of linear accelerators, as well as the other dosimetric parameters normally included in a program of quality control in radiotherapy. The average calibration factors of the accelerators for the period of approximately four years for the Clinac 600C and Clinac 6EX were (0,998 ± 0,012) and (0,996 ± 0,014), respectively. For the Clinac 2100CD 6 MV and 15 MV was (1,008 ± 0,009) and (1,006 ± 0,010), respectively, in a period of approximately four years. Statistical analysis of the three linear accelerators was found that the coefficient of variation of calibration factors had values below 2% which shows a consistency in the data. By calculating the normal distribution of calibration factors, we found that for the Clinac 600C and Clinac 2100CD, is an expected probability that more than 90% of cases the values are within acceptable limits according to the TG-142, while for the Clinac 6EX is expected around 85% since this had several exchanges of accelerator components. The values of TPR20,10 of three accelerators are practically constant and within acceptable limits according to the TG-142. It can be concluded that a detailed study of data from the calibration factor of the accelerators and TPR20,10 from a quantitative point of view, is extremely useful in a quality assurance program.
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Yang, Huiqi. "Development of computer-based algorithms for unsupervised assessment of radiotherapy contouring." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/284463.
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INTRODUCTION: Despite the advances in radiotherapy treatment delivery, target volume delineation remains one of the greatest sources of error in the radiotherapy delivery process, which can lead to poor tumour control probability and impact clinical outcome. Contouring assessments are performed to ensure high quality of target volume definition in clinical trials but this can be subjective and labour-intensive. This project addresses the hypothesis that computational segmentation techniques, with a given prior, can be used to develop an image-based tumour delineation process for contour assessments. This thesis focuses on the exploration of the segmentation techniques to develop an automated method for generating reference delineations in the setting of advanced lung cancer. The novelty of this project is in the use of the initial clinician outline as a prior for image segmentation. METHODS: Automated segmentation processes were developed for stage II and III non-small cell lung cancer using the IDEAL-CRT clinical trial dataset. Marker-controlled watershed segmentation, two active contour approaches (edge- and region-based) and graph-cut applied on superpixels were explored. k-nearest neighbour (k-NN) classification of tumour from normal tissues based on texture features was also investigated. RESULTS: 63 cases were used for development and training. Segmentation and classification performance were evaluated on an independent test set of 16 cases. Edge-based active contour segmentation achieved highest Dice similarity coefficient of 0.80 ± 0.06, followed by graphcut at 0.76 ± 0.06, watershed at 0.72 ± 0.08 and region-based active contour at 0.71 ± 0.07, with mean computational times of 192 ± 102 sec, 834 ± 438 sec, 21 ± 5 sec and 45 ± 18 sec per case respectively. Errors in accuracy of irregularly shaped lesions and segmentation leakages at the mediastinum were observed. In the distinction of tumour and non-tumour regions, misclassification errors of 14.5% and 15.5% were achieved using 16- and 8-pixel regions of interest (ROIs) respectively. Higher misclassification errors of 24.7% and 26.9% for 16- and 8-pixel ROIs were obtained in the analysis of the tumour boundary. CONCLUSIONS: Conventional image-based segmentation techniques with the application of priors are useful in automatic segmentation of tumours, although further developments are required to improve their performance. Texture classification can be useful in distinguishing tumour from non-tumour tissue, but the segmentation task at the tumour boundary is more difficult. Future work with deep-learning segmentation approaches need to be explored.
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Togno, Michele Verfasser], Jan [Akademischer Betreuer] [Wilkens, and Franz [Gutachter] Pfeiffer. "A novel ion chamber technology for quality assurance in external beam radiotherapy / Michele Togno ; Gutachter: Jan J. Wilkens, Franz Pfeiffer ; Betreuer: Jan J. Wilkens." München : Universitätsbibliothek der TU München, 2017. http://nbn-resolving.de/urn:nbn:de:bvb:91-diss-20170717-1356924-1-1.
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Togno, Michele [Verfasser], Jan J. [Akademischer Betreuer] [Gutachter] Wilkens, and Franz [Gutachter] Pfeiffer. "A novel ion chamber technology for quality assurance in external beam radiotherapy / Michele Togno ; Gutachter: Jan J. Wilkens, Franz Pfeiffer ; Betreuer: Jan J. Wilkens." München : Universitätsbibliothek der TU München, 2017. http://d-nb.info/1141296071/34.
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TORETI, DALILA L. "Aceite, comissionamento e controle de qualidade em radiocirurgia." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9479.
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IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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CAMARGO, PRISCILLA R. T. L. "Implantação de um programa de controle de qualidade para sistemas de planejamento de tratamento computadorizados de acordo com o TRS 430." reponame:Repositório Institucional do IPEN, 2006. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11412.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Kinsella, Billyndé. "The development of a radiation quality control manual by analysing the prevalance of adverse incidents during radiation therapy at Universitas annexe Bloemfontein." Thesis, Bloemfontein : Central University of Technology, Free State, 2009. http://hdl.handle.net/11462/19.
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El, Barouky Jad. "Evaluation des algorithmes de calcul de dose pour les faisceaux d’électrons utilisés en radiothérapie : comparaison aux mesures par films radiochromiques." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA11T002/document.
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La précision du calcul de dose est cruciale pour la qualité de la planification et de la réalisation des traitements en radiothérapie. L’objectif de ce travail était d’évaluer la qualité des algorithmes de calcul de dose des faisceaux d’électrons pour des conditions particulières proches des situations cliniques rencontrées. Une méthodologie spécifique de dosimétrie par films radiochromiques des faisceaux d’électrons a été développée et validée, y compris pour des situations difficiles avec une précision de 3.1% en dose absolue et 2.6% en dose relative. Cette technique a permis de développer des tests de Contrôle Qualité généralistes rapides et efficaces qui servent de base de données mesurées en cas de changement de version du système de planification de traitement et/ou d’algorithme de calcul de dose. Les mesures par films ont été comparées avec les calculs de deux algorithmes de calcul de dose Pencil Beam et Monte Carlo. Les deuxcodes ont donné des résultats similaires dans les tests d’obliquité, d’irrégularité et de DSP étendue. En revanche, les calculs Monte Carlo sont plus précis en présence d’hétérogénéités. D’autre part, cette méthode de dosimétrie par films radiochromiques a permis de développer un nouveau mode d’évaluation des plans de traitement avec des films découpés et insérés dans des fantômes anthropomorphiques (de type thorax et tête) de manière à obtenir la distribution de dose en 2D dans un plan transversal donné ; ces tests cliniques pouvant aussi être utilisés dans le cadre d’un Contrôle de Qualité interne adapté à l’activité clinique du service. La comparaison des mesures avec les calculs a montré une meilleure précision dans les calculs Monte Carlo par rapport aux calculs Pencil Beam au niveau des hétérogénéités, notamment dans les poumons, les cavités et les osIn radiotherapy, the dose calculation accuracy is crucial for the quality and the outcome of the treatments. The purpose of our study was to evaluate the accuracy of dose calculation algorithms for electron beams in situations close to clinical conditions. A new practical approach of radiochromic film dosimetry was developed and validated especially for difficult situations. An accuracy of 3.1% and 2.6% was achieved for absolute and relative dosimetry respectively. Using this technique a measured database of dose distributions was developed to form the basis of several fast and efficient QualityAssurance tests. Such tests are intended to be used also when the dose calculation algorithm is changed or the Treatment Planning System replaced. Pencil Beam and Monte Carlo dose calculations were compared to the measured data for simple geometrical phantom setups. They both gave similar results for obliquity, surface irregularity and extended SSD tests but the Monte Carlo calculation was more accurate in presence of heterogeneities. The same radiochromic film dosimetry method was applied to film cuts inserted into anthropomorphic phantoms providing a 2D dose distribution for any transverse plan. This allowed us to develop clinical test that can be also used for internal Quality Assurance purposes. As for simpler geometries, the Monte Carlo calculations showed better agreement with the measured data than the Pencil Beam calculation, especially in presence of heterogeneities such as lungs, cavities and bones
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Amaral, Leonardo Lira do. "Programa de controle da qualidade dosimétrico, validado com auxílio de filme radiocrômico, aplicado à radioterapia estereotáxica." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-16042012-144526/.
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A Radioterapia de lesões cerebrais próximas a estruturas críticas necessitam de uma alta precisão na localização e na dose. O rigor na liberação da dose deve ser acompanhado por um preciso controle da qualidade nos aparelhos que envolvam a prática. O comissionamento do sistema de planejamento consiste em averiguar e confirmar os cálculos realizados pelo sistema. Porém, mesmo com todo controle da qualidade no comissionamento, existem vários aspectos que podem influenciar na administração da dose no volume alvo, o que exige a necessidade de se fazer uma avaliação final, no ato do tratamento, in vivo. O objetivo deste trabalho é desenvolver uma técnica de dosimetria in vivo como parte de um programa de controle da qualidade em radioterapia estereotáxica. Na técnica de dosimetria in vivo, utilizaram-se segmentos de filme radiocrômico, com dimensões de 1x1 cm2, acoplados na área externa ao colimador formado por micro-lâminas, Moduleaf. Estes filmes foram inseridos na região central do feixe. Os filmes foram irradiados e calibrados para obtenção dos fatores campos, na configuração da técnica. Com estes dados foi elaborado um programa computacional, o qual calcula a densidade relativa que um filme deve adquirir quando submetido a uma exposição nesta configuração. Como a técnica de dosimetria in vivo usa os dados do TPS, validaram-se alguns parâmetros do comissionamento do TPS. Complementando o estudo da dosimetria in vivo foram avaliados cinco planos não co-planares, sendo o primeiro com 15 campos e os outros com 25 campos. Antes de iniciar o procedimento o segmento de filme era acoplado ao aparelho e após a execução do tratamento a densidade ótica era avaliada e comparada com a calculada pelo programa desenvolvido. No comissionamento, todas as dosimetrias relativas apresentaram diferenças percentuais menores que 2%, quando comparados os resultados medidos com os calculados pelo sistema de planejamento. No desenvolvimento da técnica de dosimetria in vivo, a diferença percentual média da verificação dosimétrica, no momento da irradiação, comparado com a calculada pela planilha foi de 1,5%, enquanto que a dosimetria absoluta aplicada ao controle da qualidade convencional foi aprovada com diferença percentual média de 2,5% e a função gama média encontrada foi de 97,9% dos pontos aprovados com critério de aceitação %=2% e D=2 mm. Logo, todos os dados estão em concordância com os limites estabelecidos pelo TRS-430. Desta forma, conclui-se que foi desenvolvida uma técnica de dosimetria in vivo como parte de um programa de controle da qualidade em radioterapia estereotáxica com filme radiocrômico, já que foram confirmados os parâmetros básicos do comissionamento do sistema de planejamento e a técnica foi validada com o controle de qualidade convencional nos cinco planos analisados.Radiation therapy of brain lesions near critical structures requires a highly accurate location and dose. The accuracy in dose delivery should be accompanied by an accurate quality control in devices involving the practice. The commissioning of the planning system is to ascertain and confirm the calculations performed by the system, but even with all quality control in the commissioning, there are several aspects that may influence the dosing the target volume, which necessitates the need to make a final assessment at the time of treatment, in vivo. The objective of this work is to develop a technique for in vivo dosimetry as part of quality assurance in stereotactic radiotherapy. In vivo dosimetry technique, we used segments of film radiocrômico, with dimensions of 1x1 cm2, coupled to the external area formed by the micro-collimator blades, Moduleaf. These films were inserted in the central region of the beam. The films were irradiated and calibrated to obtain factors of fields in the configuration of the technique. With these data we designed a computer program which calculates the relative density of a film must acquire when subjected to an exposure in this setting. As the technique of in vivo dosimetry using data from the TPS, validated parameters are the commissioning of the TPS. Complementing the study of in vivo dosimetry were evaluated five non-coplanar plans, the first with 15 fields and the other with 25 fields. Before starting the procedure, the film segment was attached to the unit and after the treatment is the optical density was measured and compared with those calculated by the program developed. At commissioning, all presented on dosimetry percentage differences less than 2%, when comparing the measured results with those calculated by the planning system. In developing the technique of in vivo dosimetry, the mean percent difference dosimetry verification at the time of irradiation compared with the calculated by the sheet was 1.5%, while the absolute dosimetry applied to the conventional quality control has been approved as mean percent difference 2.5% and the gamma function mean was 97.9% of the points agreed with the acceptance criterion % = 2% and D = 2 mm. Therefore, all data are in agreement with the limits set by TRS-430. Thus, we conclude that we have developed a technique for in vivo dosimetry as part of a quality assurance in stereotactic radiotherapy radiocrômico film, since some parameters were confirmed to commissioning the planning system and the technique was validated with control quality standard in five plans analyzed.
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Camargo, Priscilla Roberta Tavares Leite. "Implantação de um programa de controle de qualidade para sistemas de planejamento de tratamento computadorizados de acordo com o TRS 430." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/85/85131/tde-03052012-133401/.
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No presente trabalho serão apresentadas as diretrizes e os testes necessários para a implantação de um programa de controle de qualidade para o Eclipse 7.3.10 da Varian no Hospital das Clínicas da Faculdade de Medicina da USP, de acordo com a mais recente publicação da AIEA o TRS 430. Os testes recomendados pelo TRS 430 são basicamente divididos em testes de aceitação, comissionamento (testes dosimétricos e não dosimétricos), e testes rotineiros. O documento da AIEA está sendo implementado para o Eclipse no HC para os feixes de fótons de dois aceleradores lineares da Varian, Clinac 600C e Clinac 2100C. Os testes de aceitação verificaram parâmetros de \"hardware\"; integração do sistema \"network\"; transferência de dados, e \"softwares\". Os resultados obtidos mostraram boa concordância com as especificações do fabricante. Para os testes dosimétricos de comissionamento, foram realizadas medidas de dose absoluta para diversos arranjos experimentais. Esses valores foram comparados com os valores de dose gerados pelo SPTC. A grande maioria dos testes apresentou cerca de 90% a 80% dos pontos comparados, dentro dos níveis de tolerância, ou seja, uma boa concordância entre os valores experimentais e os valores gerados pelo SPTC. Somente arranjos de campos assimétricos apresentaram discordâncias grosseiras, mostrando a necessidade de uma investigação mais apurada para esses casos. Os testes de comissionamento não dosimétricos também apresentaram resultados excelentes, com praticamente todas as ferramentas e desempenho geral do sistema de acordo com as recomendações estipuladas no TRS 430. Foram aplicados também critérios de aceitabilidade para a comparação entre os valores de UMs gerados pelo sistema e os valores de UMs calculados manualmente. Os feixes no Eclipse foram caracterizados com dados transferidos do CadPlan e com dados provenientes do recomissionamento dos aceleradores, assim sendo, para esses testes encontrou- se uma diferença de até 3% para campos conformacionados para os dados de feixe provenientes do recomissionamento dos aceleradores, e de até 4% para os dados de feixe transferidos do CadPlan, sendo que o nível de tolerância estabelecido pelo TRS 430 para o arranjo era de 3%.This work presents the guidelines and necessary tests tom implement a quality assurance program for Eclipse 7.3.10 from Varian at Hospital das Clinicas, Sao Paulo University School of Medicine - Brazil, in accordance with the new IAEA publication TRS 430. The recommended tests for the TRS 430 air mainly classified into acceptance tests, commissioning (dosimetric and non-dosimetric tests), and routine tests. The IAEA document\'s recommendations are being implemented at the hospital for two Varian linear accelerators - Clinac 600C e Clinac 2100C. The acceptance tests verified \'hardware\', integration of network systems, data transfer and \'software\' parameters. The results obtained are in a good agreement with the manufacturer\'s specifications. Measurements of absolute dose in several set-ups were made for the commissioning dosimetric tests. These data were compared to the absolute doses determined by the TPS. The great majority of the tests showed 90% to 80% of the analyzed data in acceptance levels, with a good agreement between the experimental data and the data determined by the TPS. Only settings with asymmetric fields presented significant discords, showing the need for a more detailed inquiry for these settings. The non-dosimetric commissioning tests have also presented excellent results, with virtually all the system tools and general performance in compliance with TRS 430. The acceptance criteria have been applied for a comparison between the values of MUs generated by TPS and the calculated manually ones. The beams have been characterized for Eclipse with data transferred from CadPlan and with data from recommissioning of accelerators, so for these tests it was found a difference of at least 3% for the conformal field shape for the data originated in the beams of recommissioning and at least 4% for the data proceeded from CadPlan. The tolerance level established by TRS 430 for this setting was 3%.
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MADELIS, GEORGES. "Assurance qualite et analyse des incertitudes en radiotherapie conformationnelle pour le cancer de la prostate." Toulouse 3, 1999. http://www.theses.fr/1999TOU30055.
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L'objectif de la radiotherapie conformationnelle est d'optimiser le resultat therapeutique, c'est-a-dire ameliorer le controle local tout en respectant la toxicite des organes sains qui entourent la region tumorale. Il s'agit d'une methode de travail relativement nouvelle qui utilise le progres technologique (appareils, logiciels) pour optimiser les conditions de preparation et de mise en uvre du traitement. Elle permet ainsi une meilleure precision, tant spatiale que dosimetrique. Afin que cette precision soit effectivement atteinte, l'assurance qualite doit se conformer aux exigences de cette technique et envelopper tous les nouveaux outils et procedures utilises en radiotherapie. La presente etude d'assurance qualite et d'analyse des incertitudes fait partie de l'etude de faisabilite d'escalade de dose (phrc 95) intitulee : etude multicentrique de radiotherapie conformationnelle par accelerateur equipe d'un collimateur multilames - evaluation dans le cancer de la prostate. Dans l'etude d'assurance qualite nous avons tenu particulierement compte du caractere multicentrique de ce projet par le moyen d'intercomparaisons entre sites. Le travail presente dans ce rapport concerne les points suivants : @ l'incertitude a la definition du volume cible (ctv) et des organes a risque. @ le controle qualite des algorithmes d'expansion pour la definition du ptv. @ la verification de la dose delivree dans les conditions de reference et des donnees de base utilisees pour la planification des traitements. @ le developpement et la comparaison de differentes methodes de calcul de la probabilite de complication (ntcp) en vue d'une utilisation clinique. @ l'intercomparaison des methodes et des logiciels utilises pour la planification des traitements conformationnels. @ l'intercomparaison des donnees physiques (volumes, doses, hdv) concernant les dossiers des patients inclus dans l'etude multicentrique. @ la verification de la dose delivree par des mesures in vivo.
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Liu, Guilin Ph D. "The application of electronic portal imaging devices to radiotherapy quality assurance." 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phl7833.pdf.
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"May 2002." Bibliography: p. [211]-221. Routine quality assurance (QA) of a linear accelerator is critical to the effectiveness of radiation treatment for cancer. The studies reported in this thesis demonstrate the potential for using Electronic Portal Imaging Devices for quality assurance tests with the aim of improving the accuracy and efficiency of radiotherapy QA.
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Zwan, Benjamin J. "Time-resolved quality assurance and delivery verification for external beam radiation therapy using an electronic portal imaging device." Thesis, 2020. http://hdl.handle.net/1959.13/1431126.
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Research Doctorate - Doctor of Philosophy (PhD)Advances in science and technology have led to the development of increasingly complex delivery techniques for external beam radiation therapy (EBRT). Modern techniques such as intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT), rely on synchronization of multiple dynamic control systems and require a high degree of mechanical and dosimetric accuracy. Real-time adaptive delivery techniques, such as multileaf collimator (MLC) tracking, have even greater complexity as each treatment is modified in real time to account for measured tumor motion. Due to the technical and dynamic nature of these delivery types, dose verification and quality assurance (QA) techniques are challenging, time consuming and cannot detect all types of delivery errors. Time-resolved imaging using an electronic portal imaging device (EPID) can be used to acquire high spatial and temporal resolution images of the radiation beam. This imaging modality has the potential to address many of the challenges and shortcomings in modern EBRT delivery verification and QA. Despite this, there are a limited number of techniques in the literature which utilise this imaging modality and even fewer in routine clinical use. The overall aim of this work is to generate, test and implement a series of novel techniques for QA and verification of modern radiotherapy deliveries which rely solely on time-resolved EPID imaging. The first specific aim of this work was to develop and test a system for automated QA of the dynamic MLC using time-resolved EPID imaging. This method improves on current QA techniques by directly measuring the trajectory of each MLC leaf as a function of time during the delivery. The measured trajectories can then be used to reconstruct the dose in the patient to determine the dosimetric effect of measured MLC errors. The methodology was shown to be sensitive to a range of MLC errors, was independent of the delivery control system and could be fully automated. This MLC QA technique was then implemented in a clinical radiotherapy department and used to detect and characterize a dosimetrically significant MLC positional error. The second aim of this work was to create a comprehensive suite of tests for commissioning and ongoing QA of VMAT delivery systems relying solely on time-resolved EPID imaging. The techniques developed here were designed to systematically verify all aspects of VMAT deliveries including MLC positional accuracy, dose delivery accuracy, dose rate constancy, beam profile constancy, gantry speed constancy and synchronization between the MLC, dose rate and gantry angle. In the next phase of this work, a system was developed for real-time verification of MLC tracking radiotherapy based on EPID imaging during treatment. Time-resolved EPID imaging was utilized for clinical deliveries where MLC tracking was implemented for the treatment of lung cancer patients. This dataset was used to develop and test the methodology which aims to independently verify the delivery in real-time. It is intended that this system can be used for future MLC tracking clinical trials to detect delivery errors and improve the accuracy of treatment for MLC tracking radiotherapy. The last aim of this work was to use time-resolved EPID imaging to improve the accuracy of pre-treatment patient specific QA for IMRT and VMAT. A method was developed to correct for the energy response of the EPID to radiation that has transmitted through the MLC. This technique was incorporated into an existing EPID dose-to-water conversion model and was shown to improve the accuracy of the model for dose verification. In summary, time-resolved EPID imaging has been used to improve QA and verification for modern EBRT and been shown to address several challenges in the following specific areas: (1) QA of dynamic MLC systems, (2) QA of VMAT delivery systems, (3) delivery verification for MLC tracking radiotherapy and (4) patient-specific QA for IMRT and VMAT. It is the intention of this work to encourage and enable more widespread utilisation of time-resolved EPID imaging in clinical radiotherapy departments to improve the safety and quality of modern radiotherapy treatment.
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Δροσάτου, Καλλιόπη. "Διασφάλιση ποιότητας στη στερεοτακτική ακτινοθεραπεία και δοσιμετρία μικρών πεδίων." Thesis, 2014. http://hdl.handle.net/10889/8361.
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Η στερεοτακτική μέθοδος ακτινοθεραπείας και ακτινοχειρουργικής είναι μια νεότερη μέθοδος της ογκολογίας, που αποδεδειγμένα υπερέχει έναντι της συμβατικής μεθόδου ακτινοβόλησης, ιδιαίτερα όταν συνδυάζεται με τελευταίες τεχνικές ακτινοβόλησης, όπως το IMRT, ArcTherapy and VMAT. Χαρακτηρίζεται δε από ακτινοβόληση με ιδιαίτερα υψηλές δόσεις, συνήθως πολύ μικρών όγκων, της τάξεως του εκατοστού. Εξαιτίας αυτών, είναι επιτακτική η ανάγκη για μέγιστη ακρίβεια και αποφυγή λαθών, καθώς δεν υπάρχουν περιθώρια σφάλματος!
Κάθε ακτινοθεραπευτικό κέντρο οφείλει λοιπόν να ακολουθεί ένα ολοκληρωμένο και ιδιαίτερα αυστηρό πρόγραμμα ποιοτικού ελέγχου, θεσπίζοντας μια σειρά ελέγχων σε ημερήσια, εβδομαδιαία, μηνιαία και ετήσια βάση.
Μέθοδος: Επειδή δεν υπάρχει ένα εντεταλμένο πρωτόκολλο Ποιοτικού Ελέγχου Στερεοτακτικής Ακτινοθεραπείας με Γραμμικό Επιταχυντή, αρχικά στην εργασία αυτή έγινε μια βιβλιογραφική μελέτη για να βρεθεί το state of the art αυτού του ζητήματος και να εντοπιστούν, σε πρώτη φάση, οι επιμέρους ποιοτικοί έλεγχοι που προτείνονται για τα διάφορα μέρη της στερεοτακτικής ακτινοβόλησης (εξοπλισμός και διαδικασία). Κατόπιν, προσδιορίστηκε μια συνολική, βέλτιστη και κατάλληλη για την πλειοψηφία των ακτινοθεραπευτικών κέντρων, λίστα ελέγχων για τη Διασφάλιση της Ποιότητας στην Στερεοτακτική Ακτινοθεραπεία.
Αποτελέσματα: Ο Πίνακας των Ελέγχων που προέκυψε είναι – ως όφειλε – σύμφωνος με τα επιμέρους διεθνή πρωτόκολλα της Ευρώπης και Αμερικής. Βάσει αυτού προτείνεται ένα ολοκληρωμένο Πρόγραμμα Διασφάλισης Ποιότητας για Ακτινοθεραπευτικά Κέντρα που εφαρμόζουν στερεοταξία, το οποίο μπορεί να διαμορφωθεί από κάθε ακτινοθεραπευτικό κέντρο, βάσει των ιδιαιτεροτήτων αυτού, αλλά και να προσαρμοστεί σε μελλοντικές τεχνολογικές αλλαγές. Η εφαρμογή τέτοιων ελέγχων, τέλος, διερευνήθηκε στο ιδιωτικό θεραπευτήριο ΜΕΤΡΟΠΟΛΙΤΑΝ του Φαλήρου.
Συμπεράσματα: Το πρόγραμμα ελέγχων που προτείνεται, αν και είναι σύμφωνο με τα επιμέρους διεθνή πρωτόκολλα ποιοτικού ελέγχου για τον εξοπλισμό και τη διαδικασία της ακτινοθεραπείας, πρέπει περαιτέρω να διερευνηθεί επί της κλινικής πράξης από ακτινοθεραπευτικά κέντρα, προκειμένου να βρεθούν τυχόν αδυναμίες και ελλείψεις και τελικώς να αποτελέσει τη βάση ενός μελλοντικού Πρωτόκολλου Διασφάλισης Ποιότητας Στερεοτακτικής Ακτινοθεραπείας με Γραμμικό Επιταχυντή, εγκεκριμένου από τους αρμόδιους διεθνείς φορείς και οργανισμούς.Stereotactic Radiation Therapy (SRT) and Stereotactic RadioSurgery (SRS) are new advanced oncologic treatment modalities, which proved superior to the conventional method of irradiation, particularly when combined with latest irradiation techniques, such as IMRT, ArcTherapy and VMAT. They apply very high doses, to – usually – very small volumes (centimeters range). These characteristics mean great need for maximum accuracy and avoid mistakes, as there is no room for error! Therefore, every radiotherapy center must follow a very strict and comprehensive quality control program, adopting a series of checks on a daily, weekly, monthly and yearly basis. Method: Because there is no specific Quality Control Protocol for Stereotactic Radiotherapy using Linear Accelerator, the first part of this work was a literature study to find the state of the art of this issue and find, at first, the proposed quality controls for each part of stereotactic irradiation (equipment and process). Afterwards an overall checklist for Quality Assurance in Stereotactic Radiotherapy was defined, which was assessed as optimal and suitable for most radiotherapy centers. Results: The resulted table of checks is - as it should - in line with the different international protocols in Europe and America. Based on this, a comprehensive Quality Assurance Program for radiotherapy centers applying stereotaxis, is proposed. This may be configured and modified by each radiotherapy center, according to its specificities, and also adapt to future technological advances. Finally we look into the implementation of such controls, at the METROPOLITAN private hospital of Faliro. Conclusions: Although the recommended Control Program is consistent with the different international quality control protocols for the equipment and process of radiotherapy, the individual radiotherapy centers should further investigate this program when in clinical use, in order to find any deficiency or weakness. The ultimate goal was to create the basis for the future Quality Assurance Protocol in Stereotactic Radiotherapy with Linac, which should be approved by the competent international comities and organizations.
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Chacón, Obando David. "Desarrollo y caracterización de materiales poliméricos radiosensibles para aplicaciones dosimétricas." Doctoral thesis, 2020. http://hdl.handle.net/11086/16328.
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Tesis (Doctor en Física)--Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación, 2020.La dosimetría de gel polimérico es una alternativa no convencional, con capacidad de registrar distribuciones espaciales de dosis en 3D con alta resolución y en material tejido equivalente. La presente tesis pretende contribuir al conocimiento de este tipo de dosimetría, mediante el desarrollo, modificación e investigación de materiales poliméricos radiosensibles, aplicando diferentes métodos de lectura en los mismos, enfocando principalmente su aplicación como herramientas potenciales en la validación y control de calidad de técnicas de radioterapia avanzada. Se presenta, además, el diseñó y construyó de un instrumento analítico de bajo costo para la lectura de estos sistemas dosimétricos. Los resultados reportados demuestran la versatilidad de este tipo de dosímetro para ser modificado e implementado en diferentes aplicaciones y estudios específicos.
Polymer gel dosimetry is a non-conventional alternative, capable of registering spatial dose distributions in 3D with high resolution in a radiological tissue-equivalent material. The thesis aims to contribute to the knowledge of polymer gel dosimetry, through the development, modification, and research of radiosensitive polymeric materials, applying different readout methods to them. The main focus of these materials is to be used as tools in the verification, quality control, and assurance for advanced radiotherapy techniques. It is also presented the design and built of a home-made dedicated readout instrument for the reading of these dosimetric systems. The reported results prove the versatility of this type of dosimeter to be specifically modified and implemented in different radiotherapeutic applications and specific studies.
Fil: Chacón Obando, David. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.
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Crupi, Michael Kyle. "Assessing Patients' and Radiation Therapists’ Perceptions of Safety in Radiation Therapy and Using a Patient-provider Collaborative Checklist to Engage Patients." Thesis, 2013. http://hdl.handle.net/1807/42779.
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Approximately 52% of cancer patients require radiation therapy during the progression of their illness. Radiation therapy is a safe procedure; however, errors may occur and have the potential to harm patients. Recent studies have looked at patient engagement as a means of preventing errors in healthcare. Through interviews and focus groups, this study looks at patients’ and radiation therapists’ current perceptions of safety in radiation therapy and whether they feel that patient engagement in the form of a patient-provider collaborative checklist can improve its safety or the perception of safety. Through workflow observations and literature reviews, a patient-provider collaborative checklist was developed. Furthermore, STAI surveys were conducted to document the progression of patient anxiety through treatment. Feedback from radiation therapists demonstrated their opinions on the usability of the final iteration of the patient-provider collaborative checklist and how it could fit into the clinical setting.
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Μαρκάκη, Βασιλική. "Ανάπτυξη τεχνικών επεξεργασίας και ευθυγράμμισης ιατρικών δεδομένων με χρήση χαρτών αυτο-οργάνωσης στην ακτινοθεραπεία." Thesis, 2012. http://hdl.handle.net/10889/6481.
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Σκοπός της παρούσας διδακτορικής διατριβής είναι η ανάπτυξη αλγορίθμων επεξεργασίας ιατρικής εικόνας για την ενσωμάτωση τους σε ιατρικές εφαρμογές ακτινοθεραπευτικού ενδιαφέροντος. Οι αλγόριθμοι αυτοί στηρίζονται στην αρχή λειτουργίας των χαρτών αυτο-οργάνωσης Kohonen και αξιοποιούν την πληροφορία που περιέχεται σε περιοχές των εικόνων γύρω από σημεία ενδιαφέροντος, ώστε να εντοπίσουν αυτόματα, με ακρίβεια και αξιοπιστία, αντιστοιχίες μεταξύ των εικόνων.
Πιο συγκεκριμένα, ένας επαναληπτικός αλγόριθμος προτείνεται για την αυτόματη εύρεση αντίστοιχων σημείων σε ιατρικές εικόνες δύο διαστάσεων. Ο προτεινόμενος αλγόριθμος προϋποθέτει την εύρεση σημείων ενδιαφέροντος μόνο στη μια από τις δύο εικόνες και εντοπίζει τα αντίστοιχα σημεία στη δεύτερη εικόνα μέσα από μια επαναληπτική διαδικασία, η οποία προσομοιάζει τη φάση εκπαίδευσης του νευρωνικού δικτύου. Με βάση τα ζεύγη των αντίστοιχων σημείων, υπολογίζονται στη συνέχεια οι παράμετροι ενός μετασχηματισμού, κατάλληλου για να περιγράψει τη σχέση μεταξύ των δεδομένων εικόνων. Ο αλγόριθμος ευθυγράμμισης εφαρμόζεται σε δεδομένες εικόνες ηλεκτρονικής πυλαίας απεικόνισης (Electronic Portal Images), που λαμβάνονται πριν από κάθε συνεδρία της ακτινοθεραπείας, για τον υπολογισμό του σφάλματος τοποθέτησης του ασθενούς.
Το ζήτημα της επαλήθευσης της θέσης του ασθενούς στην ακτινοθεραπεία αντιμετωπίζεται επίσης με τη βοήθεια μιας αυτόματης μεθόδου εύρεσης αντίστοιχων σημείων σε τρισδιάστατα δεδομένα, η οποία εφαρμόζεται για την ευθυγράμμιση της αξονικής τομογραφίας του σχεδιασμού της ακτινοθεραπείας και μιας αξονικής τομογραφίας επαλήθευσης, που λαμβάνεται πριν την πρώτη συνεδρία της ακτινοθεραπείας. Ο προτεινόμενος αλγόριθμος εντοπίζει αντίστοιχα σημεία ενδιαφέροντος στις δεδομένες τομογραφικές εικόνες και υπολογίζει τις παραμέτρους ενός μη γραμμικού μετασχηματισμού ευθυγράμμισης. Μετά την ευθυγράμμιση των δύο τομογραφιών, υπολογίζεται η μετατόπιση του ισοκέντρου στην τομογραφία επαλήθευσης σε σχέση με τη θέση του ισοκέντρου που προβλέπεται στην αρχική τομογραφία του σχεδιασμού. Με την ενσωμάτωση αυτής της μεθόδου ευθυγράμμισης στη διαδικασία της ακτινοθεραπείας, ικανοποιούνται δύο ανάγκες της κλινικής πρακτικής. Αφενός, η μετατόπιση του ισοκέντρου, όπως υπολογίζεται από την προτεινόμενη μέθοδο, παρέχει μια αξιόπιστη ένδειξη για τη μετατόπιση του ασθενούς που απαιτείται πριν τη χορήγηση της ακτινοβολίας. Αφετέρου, επιχειρείται η καλύτερη αξιοποίηση των πόρων του τμήματος της ακτινοθεραπείας με τη διαδικασία της εύρεσης του ισοκέντρου της ακτινοθεραπείας να λαμβάνει χώρα στην αίθουσα του αξονικού τομογράφου και να μειώνεται συνεπώς ο χρόνος που απαιτείται για την προετοιμασία του ασθενούς στον γραμμικό επιταχυντή κατά την πρώτη συνεδρία της ακτινοθεραπείας.Aim of the present thesis is the development of image processing algorithms for radiotherapy applications. These algorithms are based on the principles of Kohonen Self Organizing Maps and exploit the information contained in image regions around distinctive points of interest, in order to determine image correspondences in an automatic, accurate and robust way. In particular, an iterative algorithm is proposed for automatic detection of point correspondences in two-dimensional medical images. The proposed algorithm requires the extraction of interest points only in one image and detects the homologous points in the second image through an iterative procedure, respective to the training phase of a neural network. Subsequently, the parameters of an appropriate registration transformation are computed to describe the mapping between the two images. The computation is based on the detected point correspondence. The proposed registration algorithm is applied to Electronic Portal Images, acquired prior to the radiotherapy treatment delivery, in order to estimate the setup error of the patient. The issue of patient position verification in radiotherapy is also addressed in the present thesis by developing an algorithm for automatic detection of point correspondences in three-dimensional medical data. The algorithm is used to register the CT data of radiotherapy planning to an additional verification CT, acquired prior to the first treatment fraction. The proposed algorithm detects corresponding points in the two CT images and computes the parameters of a non-rigid registration transformation. After the registration of the two CT images, the isocenter displacement of the verification CT is calculated with respect to the ideal isocenter position, defined in the planning CT. By integrating the proposed registration procedure in the clinical practice, two needs are met. Firstly, the isocenter displacement, calculated by the proposed method, provides a reliable indication of the patient shift, needed before the treatment delivery, for optimization of the dose delivery. Secondly, an improvement of the radiotherapy department efficiency is attempted by performing the procedure of isocenter marking in the CT scanner room and, consequently, reducing the time expenditure of the patient in the LINAC during the first radiotherapy fraction.
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Vedelago, José. "Sistemas avanzados para dosimetría de radiación ionizante." Doctoral thesis, 2019. http://hdl.handle.net/11086/14645.
Full textAbstract:
Tesis (Dr. en Física)--Universidad Nacional de Córdoba, Facultad de Matemática, Astronomía, Física y Computación, 2019.Los tratamientos con radiación contra el cáncer han evolucionado procurando aumentar su eficiencia para favorecer la recuperación de los pacientes. La complejidad de estos tratamientos de radioterapia impone requisitos a los sistemas de dosimetría de radiación ionizante. Por ello, es necesario contar con sistemas avanzados de dosimetría, que permitan satisfacer los requerimientos dosimétricos actuales. Con ese objetivo, se desarrollaron e investigaron materiales y metodologías para realizar mediciones dosimétricas en técnicas de radioterapia novedosas, dando soluciones a situaciones que exceden las posibilidades de los sistemas tradicionales.
Radiation treatments for cancer have evolved with the aim of increasing their efficiency. The complexity of these radiotherapy treatments imposes requirements on ionizing radiation dosimetry systems. Therefore, it is necessary to have advanced dosimetry systemsto fulfil current dosimetry requirements. With this objective, materials and methodologies were developed and researched to perform dosimetry measurements in novel radiotherapy techniques, providing solutions to situations that exceed the capabilities of traditional systems.
Fil: Vedelago, José. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía, Física y Computación; Argentina.