Commercial positron emission tomography scanners that use block detectors have additional blurring on spatial resolution, referred to as block effect. We studied the origin of the block effect, using experiments in which all other blurring effects were minimized and precisely determined. Bismuth germanate crystals (1 mm width) and a small (1 mm) 68Ge source were used to probe the spatial resolution of a CTI HR+ block detector and two precise translation stages to move detectors. Coincidence aperture functions for crystals in the block and for single crystals were compared. The central crystals in the block showed an additional blurring of 0.8 mm whereas the edge ones showed no additional blurring. The apparent centroids of the crystals in the block are not located at the geometric centers, which gives errors in the reconstruction algorithm assumed uniform sampling. Our results suggest that the additional blurring in scanners with block detectors is not only due to the use of block detectors.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.80887 |
| Date | January 2003 |
| Creators | Tomic, Nada |
| Contributors | Thompson, Cristopher (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: 002031540, proquestno: AAIMQ98752, Theses scanned by UMI/ProQuest. |
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