Title :
Designing position sensitive NaI(Tl) bar-detectors with an empirical model
Author :
Liu, Yinong ; Chang, Wei ; Kari, Bela
Author_Institution :
Rush Presbyterian-St. Luke´´s Med. Center, Chicago, IL, USA
Abstract :
In small position-sensitive bar-detectors, multiple internal reflection and the edge effect of scintillation light cause excessive light spread and lead to poor intrinsic spatial resolution. Surface treatment techniques have been used to limit light spread inside detectors and improve resolution performance. Since it is costly and time-consuming to build NaI(Tl) detectors to test for each variation of surface treatment, a practical model to predict the potential effectiveness of each technique could help guide detector design. An empirical model has been developed to evaluate the potential of different surface treatment techniques. In this model, a Lucite bar and a light-emitting diode are used to simulate light propagation and refraction in an NaI(Tl) bar-detector. Light sensors were suspended above the exit window with a small air gap for spatial recording of light refracted from the bar. A three-sided transverse sanded surface turned out to be the best compromise between light spread and light output among the nine different combinations of surface treatments evaluated. These results were later confirmed by experiments on NaI(Tl) bar-detectors
Keywords :
biomedical equipment; modelling; position sensitive particle detectors; scintillation counters; sodium compounds; surface treatment; thallium; Lucite bar; air gap; detector design; edge effect; empirical model; exit window; intrinsic spatial resolution; light output; light propagation; light spread; light-emitting diode; multiple internal reflection; position sensitive NaI:Tl bar detectors; practical model; refraction; resolution performance; scintillation light; spatial recording; surface treatment techniques; three-sided transverse sanded surface; Detectors; Light emitting diodes; Optical reflection; Optical refraction; Optical sensors; Optical variables control; Photonic crystals; Single photon emission computed tomography; Spatial resolution; Surface treatment;
Conference_Titel :
Nuclear Science Symposium and Medical Imaging Conference, 1992., Conference Record of the 1992 IEEE
Conference_Location :
Orlando, FL
Print_ISBN :
0-7803-0884-0
DOI :
10.1109/NSSMIC.1992.301074