In this work, various megavoltage imaging modalities such as the Portal Vision aS-500 Amorphous Silicon EPID, Portal Vision LC-250 Liquid Matrix EPID, PortPro Flouro based EPID, Kodak XV film, Kodak EDR film, and SmartCR Computer Radiography system are examined in terms of detector parameters (acquisition time, minimum dose to obtain an image, saturation dose, and grey scale) and image quality parameters (subject contrast, signal-to-noise ratio, spatial resolution, modulation transfer function, and gantry angle dependence). We found that aS-500 EPID provides better image quality as compared to the other modalities investigated in terms of quantitative parameters. Qualitatively, it also outperformed the other systems, although the differences in image quality between the systems were sometimes marginal. The fast acquisition time and the requirement of only 1 MU to generate an image also made aS-500 EPID the most appropriate imager for static IMRT dose verification. The isodose comparison between the aS-500 EPID and Kodak XV film for several IMRT QA studies corresponded within acceptable tolerance levels of +/-2 mm in most cases.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.80307 |
| Date | January 2003 |
| Creators | Kumaraswamy, Lalith K. |
| Contributors | Parker, William (advisor), Podgorsak, E. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Medical Radiation Physics.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 002031991, proquestno: AAIMQ98676, Theses scanned by UMI/ProQuest. |
Page generated in 0.002 seconds