Collimator spatial resolution
2005 (English)In: 2005 IEEE Nuclear Science Symposium Conference Record, 2005, 1717-1721 p.Conference paper (Refereed)
Pixellated detectors based on cadmium-zinc telluride (CZT) are a promising alternative to Nal-based SPECT cameras. The performance of either system Is quantitatively described In terms of resolution and sensitivity. This Investigation Is based on an analytical model published earlier, describing SPECT collimators according to the NEMA definitions of planar sensitivity and system spatial resolution without scatter. We have extended the model to Include the effect of collimator hole shape and orientation as well as collimator and detector penetration. Equations for spatial resolution are derived for Nal and CZT based SPECT systems with hexagonal, round or square parallel-hole collimators and with pinhole collimators. Standard equations for spatial resolution are valid only for square hole collimators along one of the detector axes. In any other direction, spatial resolution Is higher. The exact values depend on the hole shape and on the ratio of object-detector distance to collimator length. For pixellated pinhole detectors, similar corrections depending on the ratio of detector pixel size to the diameter of a point source projected on the detector apply. In scintillation cameras, spatial resolution Is not only Influenced by the average absorption depth In the scintillator, but It Is strongly affected by the parallax effect of the coillmator hole. Spatial resolution Is therefore lower than usually thought. We present a model that describes the performance of current SPECT collimators and permits to optimize future detector systems for high Image quality.
Place, publisher, year, edition, pages
2005. 1717-1721 p.
, IEEE Nuclear Science Symposium Conference Record, ISSN 1095-7863 ; 3
Cameras, Optical collimators, Optical resolving power, Scintillation counters, Semiconducting cadmium compounds, Sensitivity analysis, Cadmium zinc telluride (CZT), Collimator spatial resolution, Parallel hole collimators, Scintillation cameras, Radiation detectors
Other Engineering and Technologies
IdentifiersURN: urn:nbn:se:kth:diva-156268DOI: 10.1109/NSSMIC.2005.1596651ISI: 000241851902113ScopusID: 2-s2.0-33846644816ISBN: 0780392213ISBN: 9780780392212OAI: oai:DiVA.org:kth-156268DiVA: diva2:767701
Nuclear Science Symposium/Medical Imaging Conference, 23 October 2005 through 29 October 2005, Fajardo, PR
QC 201412022014-12-022014-11-262014-12-02Bibliographically approved