Relevant bibliographies by topics / Medical radiation science / Dissertations / Theses
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Dissertations / Theses on the topic 'Medical radiation science'

Author: Grafiati
Published: 4 June 2021
Last updated: 30 January 2023

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1

Sim, Jenny Hiow-Hui, and jenny som@med monash edu au. "Continuing professional development in medical radiation science: journey towards reflective practice in cyberspace." RMIT University. Medical Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20061201.102703.

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The study aimed to investigate how continuing professional development (CPD) activities, through the development of a CPD educational framework, can assist Medical Radiation Science (MRS) practitioners to engage in reflective practice while entrenched in a protocol driven workplace culture. The study, with action research as the chosen methodology, and used both quantitative and qualitative methodology, was divided into two phases. The first phase of data collection aimed to inform the researcher of the needs of the MRS profession. The second phase of the study involved the design and develo
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2

Maresse, Sharon. "Australian medical radiation science graduates’ experiences of resilience during transition to professional practice." Thesis, Curtin University, 2014. http://hdl.handle.net/20.500.11937/1624.

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Health professionals experience adversity as they make the transition from student to independent practice. Resilience during transition to practice for the medical radiation sciences (MRS) is unexamined. A grounded-theory approach was used to explore resilience among new Australian MRS professionals, resulting in a theoretical conceptualisation of resilience as a process of evolution, with phases of impact, energising, maintaining momentum, achieving equilibrium, and beating inertia. Resilience can be fostered by educators, colleagues, employers and professional organisations.
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Sim, Jenny. "Profile of Medical Radiation Science Practitioners as Lifelong Learners: Implications for the Design of Undergraduate Programs." Thesis, Curtin University, 2000. http://hdl.handle.net/20.500.11937/85.

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Literature has shown the importance of lifelong learning in the training of today's workforce and the crucial role of Higher Education in preparing graduates for lifelong learning. The aim of the current study is to establish the profile of Medical Radiation Science (MRS) practitioners as lifelong learners and to examine the implications of these findings for MRS undergraduate programs in Australia. The study builds on Candy et. al.'s 1994 report, Developing Lifelong Learners through Undergraduate Education, by drawing on the report's profile of lifelong learners and the features of the underg
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Sim, Jenny. "Profile of Medical Radiation Science Practitioners as Lifelong Learners: Implications for the Design of Undergraduate Programs." Curtin University of Technology, Department of Medical Imaging Science, 2000. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=9597.

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Literature has shown the importance of lifelong learning in the training of today's workforce and the crucial role of Higher Education in preparing graduates for lifelong learning. The aim of the current study is to establish the profile of Medical Radiation Science (MRS) practitioners as lifelong learners and to examine the implications of these findings for MRS undergraduate programs in Australia. The study builds on Candy et. al.'s 1994 report, Developing Lifelong Learners through Undergraduate Education, by drawing on the report's profile of lifelong learners and the features of the underg
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5

Andersson, Kristina. "Evaluation of uncertainties in sub-volume based image registration : master of science thesis in medical radiation physics." Thesis, Umeå universitet, Institutionen för fysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-38638.

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Physicians often utilize different imaging techniques to provide clear, visual information about internal parts of the patient. Since the different imaging modalities give different types of information, the combination of them serves as a powerful tool while determining the diagnosis, planning of treatment or during therapy follow-up. To simplify the interpretation of the image information, image registration is often used. The goal of the registration is to put different images in a common coordinate system. It is essential that the registration between the images is accurate. Normalized Mu
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Gunn, Therese. "The impact of virtual reality training on the clinical skill and confidence of medical radiation science students." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/209310/1/Therese_Gunn_Thesis.pdf.

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This study investigates the impact of virtual reality simulation training on medical radiation science students. It evaluates this by comparing clinical skills between students using traditional learning methods and those trained with the inclusion of the VR simulator and assesses the impact on student clinical confidence. This study's outcomes have highlighted the advantages of using such an innovative technique whilst demonstrating that the software itself is not enough to guarantee student learning. Instead, it requires purposeful inclusion into the curriculum with educators ensuring knowle
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7

Leghuel, Hatim A. "Radiation Backscatter of Zirconia." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1377012297.

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8

Lindqvist, Malcolm, and Gustav Eriksson. "Investigations of Electron Contamination in Photon Fluence Monitoring of Radiotherapy." Thesis, Uppsala universitet, Medicinsk strålningsvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-260659.

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During the last decades radiotherapy has made major improvements in accuracy and individualization of the treatment techniques. In this project the thickness of a tungsten filter has been optimized using both simulations and experiments in order to further reduce the uncertainty in the dose given to the patient. With the filter, a dosage with less uncertainty can be obtained and less electrons will strike the patient which means less skin damage. In the simulations a program called PENELOPE, has been used which uses Monte Carlo methods for electron and photons transports. The experiment has be
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9

Von, Aulock Maryna. "Brain compatible learning in the radiation sciences." Thesis, Peninsula Technikon, 2003. http://hdl.handle.net/20.500.11838/1549.

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Thesis (MTech (Radiography))--Peninsula Technikon, Cape Town, 2003<br>Brain Compatible Learning (BCL), as its name suggests, is a type of learning which is aligned with how the human brain naturally learns and develops. BCL offers many different options and routes to learning as alternatives to conventional 'chalk and talk' methodologies. A BCL curriculum is planned to define the structure and content of a programme of learning, but it also provides opportunities for students to participate in activities, which encourage and enhance the development of an active and deep approach t
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10

Wassberg, Cecilia. "Ultraviolet Radiation and Squamous Cell Carcinoma in Human Skin." Doctoral thesis, Uppsala University, Department of Medical Sciences, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1479.

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<p>Ultraviolet radiation (UVR) is a major risk factor for development of skin cancer. UVR-induced DNA damage and a dysfunctional p53 protein are important steps in the development of squamous cell carcinoman in human skin (SCC). The aim of the present investigation was to analyze incidence trends of SCC in Sweden, quantify the risk of second primary cancer after SCC and further analyze the effects of UVR and p53 protein in human skin <i>in vivo</i> and <i>in vitro</i>. The effect of photoprotection by sunscreens was also evaluated. </p><p>We found that the age-standardized incidence rate of SC
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11

Audet, Chantal. "NMR-based radiation dosimetry using polymer solutions." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59996.

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The spin-spin and spin-lattice relaxation times of protons on polymers, T$ sb{ rm 1p}$ and T$ sb{ rm 2p}$, respectively, have been used to probe the absorbed dose of irradiated polymer solutions in which radiation-induced changes in polymer molecular weight, M$ sb{ rm n}$, occur. The M$ sb{ rm n}$ dependencies of T$ sb{ rm 1p}$ and T$ sb{ rm 2p}$, and of the water proton T$ sb{ rm 1w}$ for solutions of poly(ethylene oxide) (PEO) in D$ sb2$O and H$ sb2$O are presented. T$ sb{ rm 1p}$ and T$ sb{ rm 1w}$ are independent of M$ sb{ rm n},$ and T$ sb{ rm 2p}$ varies with M$ sb{ rm n}$ according to a
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12

Merlin, Scott L. "Endothelin-1 and radiation-associated impotence." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0022/MQ50837.pdf.

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13

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 saturati
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14

Koirala, Nischal. "Access Blood Flow Measurement Using Angiography." Cleveland State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu153796812445051.

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15

Chakradeo, Shweta. "ROLE OF AUTOPHAGY IN THE RESPONSE OF HS578T BREAST TUMOR CELLS TO RADIATION." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/2919.

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Breast cancer is the most commonly observed cancer type in women and is the second leading cause of cancer death in women. Radiation can be used to debulk tumors prior to surgery as well as to treat patients after surgery and/or chemotherapy. Previous studies from our laboratory have shown that the anti –malarial drug chloroquine sensitizes breast cancer cell lines to radiation by suppression of autophagy which is a conservative catabolic process that can be cytoprotective. The scientific literature has demonstrated that many tumor cell systems undergo cytoprotective autophagy and that pharmac
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16

Mann, Travis L. "Patient Awareness and Knowledge of Medically Induced Radiation Exposure." ScholarWorks, 2019. https://scholarworks.waldenu.edu/dissertations/7881.

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The level of knowledge and awareness among patients about the concepts and implications of medical radiation is unknown. The purpose of this qualitative, case study was to explore patients' awareness and knowledge of information regarding this topic from their perspectives. The health belief model provided the framework for the study. A total of 20 individuals were recruited using purposive sampling. All participants were above the age of 18 in central North Carolina and had undergone or are currently undergoing medical radiation exams. Data were collected using semistructured interviews and a
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17

LeBlanc, Julie-Maude. "Interaction between cisplatin and radiation in the treatment of ovarian cancer cells." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26337.

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The A2780s is a cisplatin and radiation-sensitive human ovarian carcinoma cell line from which the more resistant variant, A2780cp, was derived. In vitro experiments on the radiosensitivity of these cells with different treatments may be representative of the in vivo radiosensitivity, and maybe of use to patients receiving radiotherapy. Therefore, many studies have been directed at evaluation of the inhibition of DNA repair in order to improve radiotherapy. Previous studies showed that drugs and hyperthermia are repair inhibitors increasing the effectiveness of radiation. Cisplatin can also r
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18

Sarfehnia, Arman. "The use of orthogonal bremsstrahlung beams for imaging in radiation therapy /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99203.

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Since portal images are created by megavoltage, forward-directed bremsstrahlung beams, their image quality is inferior to that of images produced by kilovoltage beams. In this study, characteristics of orthogonal bremsstrahlung photons produced by megavoltage electron beams were studied and their suitability for radiotherapy imaging was evaluated. Orthogonal bremsstrahlung beams with kilovoltage effective energies can be obtained from megavoltage electrons striking low atomic number targets. A 10 MeV electron beam emerging out of the research port of a Varian Clinac-18 linac was made to strike
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Stroian, Gabriela. "Optimized scanning procedures for 4D CT data acquisition in radiation therapy." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84077.

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The goal of conformal radiation techniques is to improve local tumor control through dose escalation to target volumes while at the same time sparing surrounding healthy tissue. Accurate target volume delineation is essential in achieving this goal to avoid inadequate tumor coverage and/or irradiation of an unnecessary volume of healthy tissue. Respiratory motion is known to be the largest intra-fractional organ motion and the most significant source of uncertainty in treatment planning for chest lesions. A method to minimize effects of respiratory motion is to use four-dimensional (4D)
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20

Kased, Azad, and Peter Quach. "A Questionnaire Study on Patient Knowledge on X-ray Radiation Effects on Human Health from Dental Radiographic Examination." Thesis, Umeå universitet, Institutionen för odontologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-143417.

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Swedish Radiation Safety Authority has suggested guide-lines regarding information to individuals who undergo radiographic examinations. The guide-lines concerns medical care but patients in dental care can also be expected to have a wish to be informed about ionizing radiation. The main objective was to find out the patient’s perception of their knowledge about x-ray radiation and if they have a need to know more about x-rays. A questionnaire study was performed at two public dental clinics in Sweden during a twomonth period in the summer 2016. Patients ≥ 18 years old who gave their consent t
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21

Hristov, Dimitre H. "Development of techniques for optimization and verification of radiation treatments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0021/NQ44454.pdf.

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22

Elliott, Adam S. "Investigation of properties of a new liquid ionization chamber for radiation dosimetry." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101120.

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Liquid ionization chambers have characteristics that can remedy some of the drawbacks of air-filled ionization chamber dosimetry: large sensitive volumes, fluence perturbations, and energy dependence. However, high ion recombination rates can be a significant problem in liquid chambers. In this work, we have investigated properties of a new liquid chamber, called the GLIC-03 (Guarded Liquid Ionization Chamber), including chamber stability, reproducibility, and establishing recombination corrections. The response varied by less than 1% over 10 hours, and was reproducible within 1.5% of the mean
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23

Stewart, Kristin J. "Accurate radiation dosimetry using liquid- or air-filled plane-parallel ionization chambers." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29576.

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To optimize delivery of radiation therapy treatments, accurate knowledge of absorbed dose in the clinical beam is essential. In this work we investigated issues related to the use of different types of ionization chambers for accurate radiation dosimetry. We determined values of Pwall at 60Co for plane-parallel chambers and used them to derive the conversion factors kecal k'R 50 or kQ for a 20 MeV electron beam. Our results agreed within 0.4% with kQ values given in the IAEA TRS-398 protocol, but differences of up to 1.8% were found between our kecalk' R50 values and those in the AAPM TG-51 pr
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24

Wilson, Eden. "Radiation Sensitization of Breast Cancer Cells by Vitamin D Through the Promotion of Autophagic Cell Death." VCU Scholars Compass, 2012. http://scholarscompass.vcu.edu/etd/370.

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Radiation therapy is a widely used tool in cancer therapy and is frequently offered as the first line of treatment for cancers of the breast. While radiotherapy is often initially effective in killing tumor cells or suppressing their growth, there are factors that confer tumor cell resistance to irradiation. Development of resistance may lead to disease recurrence despite the use of surgery, chemotherapy and radiation therapy. A primary goal of the studies in Dr. Gewirtz’s laboratory is to develop strategies to overcome resistance to radiation (and chemotherapy) in breast cancer, with the ult
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Rigaud, Gaël. "Study of generalized Radon transforms and applications in Compton scattering tomography." Phd thesis, Université de Cergy Pontoise, 2013. http://tel.archives-ouvertes.fr/tel-00945739.

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Since the advent of the first ionizing radiation imaging devices initiated by Godfrey Newbold Hounsfield and Allan MacLeod Cormack, Nobel Prizes in 1979, the requirement for new non-invasive imaging techniques has grown. These techniques rely upon the properties of penetration in the matter of X and gamma radiation for detecting a hidden structure without destroying the illuminated environment. They are used in many fields ranging from medical imaging to non-destructive testing through. However, the techniques used so far suffer severe degradation in the quality of measurement and reconstructe
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Cooper, Sarah Louise Pamela. "Base excision repair of radiation-induced DNA damage in mammalian cells." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:2c4b3d1e-67c3-4da5-8967-3080b1ebf27a.

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A specific feature of ionising radiation is the formation of clustered DNA damage, where two or more lesions form within one to two helical turns of the DNA induced by a single radiation track. The complexity of ionising radiation-induced DNA damage increases with increasing ionisation density and it has been shown that complex DNA damage has reduced efficiency of repairability. In mammalian cells, base excision repair (BER) is the predominant pathway for the repair of non-DSB clustered DNA lesions and is split into two sub-pathways known as short patch (SP) BER and long patch (LP) BER. SP-BER
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Vedam, Subrahmanya. "Management of Respiratory Motion in Radiation Oncology." VCU Scholars Compass, 2002. http://scholarscompass.vcu.edu/etd_retro/162.

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Respiratory motion poses significant problems in the radiotherapy of tumors located at sites (lung, liver, pancreas, breast) that are affected by such motion. Effects of respiratory motion on the different stages of the radiotherapy process (imaging, treatment planning and treatment delivery), has formed the focus of significant research over the last decade. Results from such research have revealed that respiratory motion affects the instantaneous position of almost all structures in the thorax and abdomen to different degrees based on their corresponding anatomic location and muscular attach
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Bakhshwin, Duaa. "Cytoprotective versus Non-protective Autophagy Induced by Radiation in Head and Neck Cancer Cells." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3453.

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The primary treatment options for head and neck cancer are radiation therapy or surgery, or both combined; chemotherapy is often used as an additional, or adjuvant, treatment. Patients treated with radiotherapy are exposed to a high cumulative dose of radiation over a period of time and there is a 17-33% chance of recurrence. High cumulative doses of radiation, a long time course of treatment, side effects and the possibility of recurrence provide the rationale for developing approaches for radiation sensitization, which could be helpful to patients in decreasing the dose, duration of radiatio
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Duchesne, Simon. "An appearance-based method for the segmentation of medial temporal lobe structures from MR images /." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33753.

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A new paradigm for the characterization of structure appearance is proposed, based on a combination of grey-level intensity data and a shape descriptor derived from a priori Principal Components Analysis of 3D deformation vector fields. Generated without external intervention, it extends more classical, 2D manual landmark-based shape models. Application of this novel concept leads to a method for the segmentation of medial temporal lobe structures from brain magnetic resonance images. The strategy employed for segmentation is similar to that used in other appearance-based approaches, while the
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30

Sirois, Luc M. "3-D automatic anatomy-based image registration in portal imaging." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0025/MQ50880.pdf.

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Tremblay, Hugo. "La tomographie par émission de positons à l'étude de la réponse hémodynamique temporelle induite par activation cérébrale (TEP-RHETIAC)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ64469.pdf.

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32

Suk, Joon Young. "Improving the spatial resolution of the MicroPET R4 scanner by wobbling the bed." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101799.

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The MicroPET R-4 scanner was designed for imaging small rodents such as mice and rats. In many cases its spatial resolution is not good enough to perform the required task. We have implemented an eccentric motion (commonly referred to as wobbling) which is applied to the bed during scanning.<br>The program which histograms the list-mode data was rewritten to increase the spatial sampling by incorporating the wobble position in the sinograms. The corrections for the dwell time, apparent crystal location, and crystal-pair efficiency are applied within the program. A series of scans were performe
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Asiev, Krum. "Validation of a Monte Carlo based treatment planning system (TPS) for electron beams." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101700.

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A commercial electron dose calculation software (Eclipse TM) implementation based on the Macro Monte Carlo algorithm has been introduced. Eclipse™ initial configurations were performed for all available electron beam energies 6, 9, 12, 16, and 20 MeV. We evaluated the electron Monte Carlo (eMC) module of the Eclipse™ using a verification data set comprised of depth dose curves, profiles, Relative Output Factors (ROF), and 2-0 dose distributions in the transverse plane in a homogeneous phantom. The verification data set was comprised of measurements performed for combinations of 6, 9, 12, 16, a
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Fraser, Danielle J. "Characterizing ionization chamber dosimetry in inverse planned IMRT fields." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84031.

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It is standard practice in radiation therapy to have two independent calculations for the number of monitor units used in patient treatment plans. The relationship between monitor units and absorbed dose to water is sophisticated for MLC-based IMRT. Verification measurements of absorbed dose to water with ionization chambers in MLC-based IMRT fields remains uncertain and the accuracy of computer modeling is limited by the physics assumptions used. In this thesis, point dose measurements from three cylindrical ionization chambers of different collecting volumes are evaluated against the
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Mark, Clarisse Ildikó. "Image-guided radiotherapy using 2D and 3D ultrasound combined with Monte Carlo dose calculations in prostate treatments." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98761.

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Two ultrasound systems were studied to investigate the effects of positional and volumetric prostate variations on dosimetry over the course of external radiation therapy. A 2D system, currently used at the Montreal General Hospital for patient repositioning, was compared to a 3D system invented recently. Prostate variations were quantified from ultrasound images acquired daily during a 2003 clinical study. A method was devised to introduce ultrasound information in a Monte Carlo Treatment Planning System previously developed at McGill. Patient repositioning was evaluated for both systems usin
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Lemire, Matthieu. "Accurate surface dose measurements in CT examinations using high sensitivity MOSFET dosimeters calibrated by Monte Carlo simulations." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98747.

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The objective of this work is to use MOSFET dosimeters to accurately measure surface dose delivered during CT examinations in various scanning conditions. To achieve this, the behaviour of MOSFETs under kilovoltage x-ray irradiation first needed to be investigated. A dose-to-dose reproducibility of 4.5%, and a mean change in sensitivity response of 10.4% with accumulated dose were measured. A Monte Carlo model of the x-ray source of a PQ5000 CT simulator was built and validated in order to investigate the MOSFET response characteristics and perform dose calculations. An over-response of 10% wa
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Alexander, Andrew William. "MMCTP : a radiotherapy research environment for Monte Carlo and patient-specific treatment planning." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101699.

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Accurate dose calculations and analysis tools are essential to radiotherapy treatment planning. Radiotherapy deliveries utilize the information provided by the treatment planning system and it is generally accepted that clinical outcome can be improved if accuracy in the dose delivery is further improved. Proven Monte Carlo calculations increase the planning accuracy however, most radiotherapy departments do not use Monte Carlo. The McGill Monte Carlo treatment planning system, MMCTP, provides a flexible software environment to integrate Monte Carlo planning with current and new treatment moda
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Reynard, Eric P. "Rotational total skin electron irradiation (RTSEI) with a 6 MeV electron linear accelerator." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101800.

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The rotational total skin electron irradiation technique at the McGill University Health Centre has undergone several developments over the past few years. Replacement of the formerly used linear accelerator has prompted many modifications to the previously reported technique. With the current technique, the patient is treated while standing on a rotating platform, with a single large field at a source to surface distance of 378 cm. The electron field is produced by a Varian 21EX linear accelerator using the commercially developed 6 MeV high dose rate total skin electron mode, along with a cus
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Ceusan, Florin. "An examination of peripheral dose in linac-based cancer treatment /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97921.

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The thesis work contains two related projects. The first project examines the characteristics of the Farmer-type ionization chamber (Farmer-type IC 2571 A) used in our experiments. An investigation was carried out to determine if the simplified "two-voltage technique" used in clinics is sufficiently accurate for saturation current estimation. Three models were used to fit the measured currents and to estimate the saturation current. The estimation was carried out by measuring the currents set-up in the Farmer-type IC while varying the applied voltages, for both polarities, for fixed and variab
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Duchesne, Caroline. "Electron arc therapy using an Electa SL-25 linear accelerator at Maisonneuve-Rosemont Hospital (Montreal, Canada)." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97944.

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Electron arc therapy is a special radiotherapeutic technique using a rotational electron beam in the treatment of large superficial tumours following curved surfaces. In those cases, arc therapy offers the best way to optimize dose uniformity while sparing healthy tissues and critical organs. The use of this technique overcomes under or over dosage problems caused by field junctions. However, electron arc therapy presents important challenges in terms of dosimetry and treatment planning.<br>Clinical implementation of electron arc therapy requires the study of many parameters of influence such
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Zakikhani, Ramtin. "Calculated perturbation factors for the NACP-02 plane-parallel ionization chamber irradiated in water by megavoltage electron beams." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99213.

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Measurements of absorbed dose to water in megavoltage electron beams are carried out with cylindrical or plane-parallel ionization chambers. The perturbation factor associated with plane-parallel ionization chambers that have sufficiently large guard rings is assumed to be unity. The NACP-02 chamber is one such chamber that we have investigated in order to determine if this assumption is valid. By performing Monte Carlo simulations with the EGSnrc code, water-to-air Spencer-Attix stopping powers and perturbation factors were calculated in water with a detailed model of the NACP chamber that wa
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Doucet, Robert. "Experimental verification of Monte Carlo calculated dose distributions for clinical electron beams." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33750.

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Current electron beam treatment planning algorithms are inadequate to calculate dose distributions in heterogeneous phantoms. Fast Monte Carlo algorithms are accurate in general but their clinical implementation needs validation. Calculations of electron beam dose distributions performed using the fast Monte Carlo system XVMC and the well-benchmarked general-purpose Monte Carlo code EGSnrc were compared with measurements. Irradiations were performed using the 9 MeV and 15 MeV beams from the Clinac 18 accelerator with standard conditions. Percent depth doses and lateral profiles were measured w
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43

St, James Sara. "The effect of changing gamma-ray interaction depth on the "block effect" in PET /." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84076.

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The block effect in Positron Emission Tomography (PET) is the degradation in spatial resolution that is seen when there are more scintillation crystals than photomultiplier tubes in a detector.<br>We measured the block effect in detectors from three PET scanners: the Siemens-CTI HR+, the GE Advance, and the Siemens-CTI HI-REZ. In the CTI HR+ the block effect was 0.7 mm in the central crystals, and negligible for the edge crystals. In the GE Advance the block effect was 0.6 mm for the central crystals, and 0.5 mm for the edge crystals. In the CTI HI-REZ detector the block effect varied f
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Boudreau, Chantal. "The use of inhomogeneity corrections for inverse planned IMRT /." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81268.

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In this thesis, the use of inhomogeneity corrections in intensity modulated radiotherapy (IMRT) inverse treatment planning is investigated. Firstly, the dosimetric consequences of CT beam hardening artifacts present on images used for treatment planning are estimated and found to be of little clinical significance (<1% dose difference). Secondly, experiments to evaluate the PEREGRINE Monte Carlo system (Nomos, Cranberry, PA) are undertaken for a 6 MV photon beam. The use of inhomogeneity corrections in clinical treatment planning is assessed for five clinical head and neck cancer cases.
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Belanger, Philippe. "MR based frickle-gelatin dosimetry : uncertainty evaluation and computerised analysis of measured dose distributions." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32759.

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Dynamically delivered intensity modulated beams (IMBs) pose unique verification problems that may be addressed with the use of integrating continuous 3D dosimeters such as gel based Fricke dosimeters. Accurate knowledge of the ability of these dosimeters to measure adequately and precisely the delivered dose is a prerequisite for their clinical use. The magnetic properties of the ferrous and ferric ions present in the gel based Fricke dosimeter after its irradiation are the basis for the use of magnetic resonance imaging (MRI) in the measurement of dose. This thesis presents the investigation
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Albaret, Claude. "Automated system for Monte Carlo determination of cutout factors of arbitrarily shaped electron beams and experimental verification of Monte Carlo calculated dose distributions." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=81259.

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Dose predictions by Monte-Carlo (MC) techniques could alleviate the measurement load required in linac commissioning and clinical radiotherapy practice, where small or irregular electron fields are routinely encountered. In particular, this study focused on the MC calculation of cutout factors for clinical electron beams. A MC model for a Varian linac CL2300C/D was built and validated for all electron energies and applicators. A MC user code for simulation of irregular cutouts was then developed and validated. Supported by a home-developed graphical user interface, it determines in situ
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Camborde, Marie-Laure A. "Use of beta-gamma coincidence to improve the quality of transmission scans for PET." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33723.

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The availability of accurately aligned, whole body, functional PET images has a significant impact on the diagnosis of malignant disease and on identifying and localizing metastasis. Gamma ray attenuation correction is essential in all quantitative PET studies.<br>The object of this study was to explore the possibility of using beta-gamma coincidence as an attenuation correction technique in order to improve transmission scan image quality.<br>This study consisted of testing and implementing a beta-gamma attenuation correction technique on an animal PET scanner. In its final form the system us
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Huang, Vicky W. "Validation of total skin electron therapy by the Monte Carlo technique." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82253.

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The goal of Total Skin Electron Therapy (TSET) is to deliver a uniform dose to the patient's entire skin to a limited depth while sparing the body organs. Due to the laborious commissioning process, it is helpful to use the Monte Carlo (MC) method for the procedure and treatment planning. Calculations of dosimetric quantities were performed with EGSnrc/BEAM MC codes as well as with the fast MC code XVMC. The linac model for a 6 MeV Varian CL21EX accelerator was established by measuring the electron focal spot size with a slit camera. Using this measured focal spot value in our proposed
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Watkins, W. Tyler. "Optimization of Radiation Therapy in Time-Dependent Anatomy." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3069.

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The objective of this dissertation is to develop treatment planning techniques that have the potential to improve radiation therapy of time-dependent (4D) anatomy. Specifically, this study examines dose estimation, dose evaluation, and decision making in the context of optimizing lung cancer radiation therapy. Two methods of dose estimation are compared in patients with locally advanced and early stage lung cancer: dose computed on a single image (3D-dose) and deformably registered, accumulated dose (or 4D-dose). The results indicate that differences between 3D- and 4D- dose are not signi
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Le, Jade. "THE ROLE OF CYTOPROTECTIVE AND NON-PROTECTIVE AUTOPHAGY IN RADIATION SENSITIVITY IN BREAST TUMOR CELLS." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3425.

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In general, ionizing radiation promotes cytoprotective autophagy in a majority of breast tumor cells. Previous studies from our laboratory indicated that radiation (5x2 Gy) induces cytoprotective autophagy in MCF-7 cells. In the current work, inhibition of autophagy by silencing of Beclin-1 in MCF-7 cells resulted in an increase in sensitivity to radiation based both on cell number and clonogenic survival; however, there was no increase in apoptosis and the basis for this sensitization is currently under investigation. Unexpectedly, enhancement of autophagy by silencing of Bcl-2 also led to an
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