Theoretical Bounds and Optimal Configurations for Multi-Pinhole SPECT
2009 (English)In: 2008 IEEE NUCLEAR SCIENCE SYMPOSIUM AND MEDICAL IMAGING CONFERENCE (2008 NSS/MIC), 2009, 5020-5022 p.Conference paper (Refereed)
The pinhole geometry in SPECT has an inherent trade-off between resolution and sensitivity. High resolution requires a small aperture which on the other hand directly reduces the rate of detected photons. Recent systems overcome this to some extent by using multiple pinholes spread out around the imaging object, effectively increasing the sensitivity with a factor equal to the number of pinholes. The images of each pinhole must fit on the detector without overlap. This creates another trade-off between resolution, sensitivity and the field-of-view (FOV) of the system. The present work analytically analyzes the properties of the multi-pinhole SPECT geometry. Optimal configurations are identified and characterized. One of the main results is that there exists a theoretical upper bound for the sensitivity given the resolution and the FOV. This upper bound is proportional to the square of the resolution and inversely proportional to the square FOV diameter. This means that if we want to improve the resolution by a factor of ten, the sensitivity will go down a factor 100, unless we decrease the FOV an equal amount. The bound can not be broken even if the detector sphere is infinitely large. One important parameter when designing a system is how close it will be to its theoretical bound. The closer to the bound the more extreme the system will be, in terms of size and number of pinholes. A moderate distance away from the bound the proportions of the system are more realistic.
Place, publisher, year, edition, pages
2009. 5020-5022 p.
, IEEE NUCLEAR SCIENCE SYMPOSIUM - CONFERENCE RECORD, ISSN 1082-3654
Detected photons, High resolution, Imaging objects, Multiple pinholes, Optimal configurations, Pinhole geometry, Pinhole SPECT, Small aperture, Theoretical bounds, Upper Bound
Radiology, Nuclear Medicine and Medical Imaging
IdentifiersURN: urn:nbn:se:kth:diva-30735DOI: 10.1109/NSSMIC.2008.4774368ISI: 000268656002109ScopusID: 2-s2.0-67649191532ISBN: 978-1-4244-2714-7OAI: oai:DiVA.org:kth-30735DiVA: diva2:401982
IEEE Nuclear Science Symposium/Medical Imaging Conference, Dresden, GERMANY, OCT 19-25, 2008
QC 201103042011-03-042011-03-042011-03-04Bibliographically approved