Development and calibration of a new gamma camera detector using large square Photomultiplier Tubes

Abstract

Large area scintillation detectors applied in gamma cameras as well as Single Photon Computed Tomography (SPECT) systems, have a major role in in-vivo functional imaging. Most of the gamma detectors utilize hexagonal arrangement of Photomultiplier Tubes (PMTs). In this work we applied large square-shaped PMTs with row/column arrangement and positioning. The Use of large square PMTs reduces dead zones in the detector surface. However, the conventional center of gravity method for positioning may not introduce an acceptable result. Hence, the digital correlated signal enhancement (CSE) algorithm was optimized to obtain better linearity and spatial resolution in the developed detector. The performance of the developed detector was evaluated based on NEMA-NU1-2007 standard. The acquired images using this method showed acceptable uniformity and linearity comparing to three commercial gamma cameras. Also the intrinsic and extrinsic spatial resolutions with low-energy high-resolution (LEHR) collimator at 10 cm from surface of the detector were 3.7 mm and 7.5 mm, respectively. The energy resolution of the camera was measured 9.5%. The performance evaluation demonstrated that the developed detector maintains image quality with a reduced number of used PMTs relative to the detection area.

Standard SPECT myocardial perfusion estimation from half-time acquisitions using deep convolutional residual neural networks

“…Although the ProSPECT scanner used in this work, designed and built by our group, is not yet commercially available in many countries, its technical performance exhibited comparable performance in terms of sensitivity, spatial and energy resolution to other commercially available SPECT cameras. 25 Moreover, this study was conducted to investigate the potential of a novel deep learning-based low-dose/fast cardiac SPECT imaging, which is applicable on any SPECT camera offering sufficient flexibility for data acquisition. Hence, similar outcomes are expected when applying this approach on other commercial SPECT cameras.…”

“…MPI-SPECT imaging was performed on fixed 90°angle dual-head ProSPECT dedicated cardiac SPECT camera. 25 The ProSPECT detector is composed of Thallium-activated Sodium Iodide (NaI(Tl)) crystal having a size of 40 9 25 cm 2 and 9.5 mm thickness. A square array of PMTs (24 pcs, 76 9 76 mm) was optically coupled to a 20-mm thick fused-quartz light-guide using a silicon-based curing compound as optical glue.…”

“…The energy resolution and sensitivity were 9.5% and 5.19 cpm/kBq, respectively. 25 This prospective study included a cohort of 363 patients with different clinical indications (normal, ischemia, and infarct) referred for MPI-SPECT imaging. Gated MPI-SPECT stress imaging was preformed 45-60 min after intravenous administration of 555-925 MBq of 99m Tc-sestamibi.…”

Development of novel and low-cost readout electronics for large FOV gamma camera detector

“…A minimum of 10 k counts for each central pixel must be collected. These calibration methods have been described in our previous works [19].…”

“…Anger logic, based on the center of gravity algorithm, is a well-known method but suffers from poor spatial resolution and strong FOV compression [14]. Different algorithms have been introduced to improve spatial resolution in gamma cameras [19][20][21][22]. Because we used square PMTs in our developed detector, the CSE method was chosen as the positioning method.…”