Microcomputed tomography dosimetry and image quality in preclinical image-guided radiation therapy

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dc.contributor.authorJohnstone, Christopher Daniel
dc.contributor.supervisorBazalova-Carter, Magdalena
dc.date.accessioned2019-04-29T19:41:56Z
dc.date.available2019-04-29T19:41:56Z
dc.date.copyright2019en_US
dc.date.issued2019-04-29
dc.degree.departmentDepartment of Physics and Astronomyen_US
dc.degree.levelDoctor of Philosophy Ph.D.en_US
dc.description.abstractMotivated by the need to standardize preclinical imaging for image-guided radiation therapy (IGRT), we examine the parameters that influence microcomputed tomography (microCT) scans in the realm of image quality and absorbed dose to tissue, including therapy beam measurements of small fields. Preclinical radiation research aims to understand radiation-induced effects in living tissues to improve quality of life. Small targets and low kilovoltage x-rays create challenges that do not arise in clinical radiation therapy. Evidence based on our multi-institutional study reveals a considerable aberration in microCT image quality from one institution to the next. We propose the adoption of recommended tolerance levels to provide a baseline for producing satisfactory and reproducible microCT image quality scans for accurate dose delivery in preclinical IGRT. Absorbed dose imparted by these microCT images may produce deterministic effects that can negatively influence a radiobiological study. Through Monte Carlo (MC) methods we establish absorbed microCT imaging dose to a variety of tissues and murine sizes for a comprehensive combination of imaging parameters. Radiation beam quality in the small confines of a preclinical irradiator is also established to quantify the effects of beam scatter on half-value layer measurements. MicroCT scans of varying imaging protocols are also compared for murine subjects. Absorbed imaging dose to tissues are established and presented alongside their respective microCT images, providing a visual bridge to systematically link image quality and imaging dose. We then characterize a novel small plastic scintillating dosimeter to experimentally measure microCT imaging and therapy beams in real-time. The presented scintillating dosimeter is specifically characterized for the low energies and small fields found in preclinical research. Beam output is measured for small fields previously only achievable using film. Finally, quality assurance tests are recommended for a preclinical IGRT unit. Within this dissertation, a narrative is presented for guiding preclinical radiotherapy towards producing high quality microCT images with an understanding of the absorbed imaging dose deposited to tissues, including providing a tool to measure small radiation fields.en_US
dc.description.scholarlevelGraduateen_US
dc.identifier.bibliographicCitationCD Johnstone, P Lindsay, EE Graves, E Wong, JR Perez, Y Poirier, Y Ben- Bouchta, T Kanesalingam, H Chen, AE Rubinstein, K Sheng, and M Bazalova- Carter. Multi-institutional MicroCT Image Comparison of Image-Guided Small Animal Irradiators. Physics in Medicine & Biology, 14(62) 2017.en_US
dc.identifier.bibliographicCitationCD Johnstone and M Bazalova-Carter. MicroCT Imaging Dose to Mouse Organs Using a Validated Monte Carlo Model of the Small Animal Radiation Research Platform (SARRP). Physics in Medicine & Biology, 11(63) 2018.en_US
dc.identifier.bibliographicCitationCD Johnstone, F Therriault-Proulx, L Beaulieu, and M Bazalova-Carter. Characterization of a Plastic Scintillating Detector for the Small Animal Radiation Research Platform (SARRP). Medical Physics, 46(1) 2019.en_US
dc.identifier.urihttp://hdl.handle.net/1828/10789
dc.languageEnglisheng
dc.language.isoenen_US
dc.rightsAvailable to the World Wide Weben_US
dc.subjectMicroCTen_US
dc.subjectMicrocomputed Tomographyen_US
dc.subjectDosimetryen_US
dc.subjectDoseen_US
dc.subjectImage Qualityen_US
dc.subjectImage-Guideden_US
dc.subjectRadiation Therapyen_US
dc.subjectSmall Animal Irradiatoren_US
dc.subjectSARRPen_US
dc.subjectJohnstoneen_US
dc.subjectImaging Doseen_US
dc.subjectSmall Fielden_US
dc.titleMicrocomputed tomography dosimetry and image quality in preclinical image-guided radiation therapyen_US
dc.typeThesisen_US

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