Imaging performance comparison between a scintillator based and a CdTe semiconductor based photon counting compact gamma camera

Abstract

The authors report on the performance of two small field of view, compact gamma cameras working in single photon counting in planar imaging tests at 122 and 140 keV. The first camera is based on a LaBr3: Ce scintillator continuous crystal (49 x 49 x 5 mm3) assembled with a flat panel multianode photomultiplier tube with parallel readout. The second one belongs to the class of semiconductor hybrid pixel detectors, specifically, a CdTe pixel detector (14 x 14 x 1 mm3) with 256 x 256 square pixels and a pitch of 55 microm, read out by a CMOS single photon counting integrated circuit of the Medipix2 series. The scintillation camera was operated with selectable energy window while the CdTe camera was operated with a single low-energy detection threshold of about 20 keV, i.e., without energy discrimination. The detectors were coupled to pinhole or parallel-hole high-resolution collimators. The evaluation of their overall performance in basic imaging tasks is presented through measurements of their detection efficiency, intrinsic spatial resolution, noise, image SNR, and contrast recovery. The scintillation and CdTe cameras showed, respectively, detection efficiencies at 122 keV of 83% and 45%, intrinsic spatial resolutions of 0.9 mm and 75 microm, and total background noises of 40.5 and 1.6 cps. Imaging tests with high-resolution parallel-hole and pinhole collimators are also reported.

SPECT detectors: the Anger Camera and beyond

“…More recently, there has been considerable excitement surrounding lanthanum bromide (most commonly LaBr 3 (Ce)) (Shah et al ., 2003) and lanthanum chloride (LaCl 3 ) (van Loef et al ., 2001) scintillators of various types owing to their high light output and, consequently, their improved energy resolution (~6% at 140 keV (Pani et al, 2006)) in comparison to other scintillators. While the size of the crystals grown to date have been small in comparison to NaI(Tl), a number of investigators have made measurements with small LaBr-based imaging detectors (Despres et al ., 2006; Russo et al ., 2009). …”

Method for measuring the focal spot size of an x‐ray tube using a coded aperture mask and a digital detector

“…The Medipix2 silicon detector system is read out by a dedicated serial interface 23 and custom software; 24 a complete description of the Medipix2 system coupled to a CdTe detector for nuclear medicine imaging can be found in Ref. 25. The flat panel detector is read out via a PCI-1424 digital frame grabber ͑National Instruments, Austin, TX͒ controlled by a home-made application software written in C-language in a National Instruments LabWindows/CVI graphical development environment developed for a cone-beam breast computed tomography scanner, as described in Refs.…”

Cadmium telluride semiconductor detector for improved spatial and energy resolution radioisotopic imaging

“…[1915] Some characteristics of the scintillators which are used, or under study and progress, for gamma-ray detection in medical imaging are presented in Table 1. [1216]…”