CZT Detector Based Systems for Imaging Applications

1861 Objectives To investigate the performance of CZT gamma and x-ray detector based imaging systems for medical imaging applications, including SPECT and energy-discriminating photon-counting (EDPC) x-ray imaging. Methods In the past we grew CZT using a High-Pressure Bridgman (HPB) method, but recently by using a Travelling Heater Method (THM) that we fabricated into detectors suitable for SPECT gamma camera and EDPC x-ray applications, such as bone mineral densitometry (BMD). Various customers have incorporated our detectors into their commercial imaging systems. Recently, we have designed and built camera subsystems that utilize these detectors. The first, based on the H3D ASIC from BNL was built to form an arbitrary sized array of integrated modules, each with CZT sensor and front-end read-out electronics. The second, based on the MW ASIC from BNL was built to form a linear array with 5 energy bins. Results The transition to THM from HPB grown CZT has resulted in a significant increase uniformity and single-crystal yield, resulting in higher performance and lower price. Customer applications have included small-animal SPECT and molecular breast imaging (MBI). We have built a small field of view gamma camera (22x22 pixels, 4.4cm square) appropriate for thyroid, sentinel lymph node, and breast biopsy imaging. We have scaled up this camera to a 15.4 cm x 22 cm size for MBI, cardiac, and brain applications, and it can be scaled larger for whole-body SPECT. Customer applications for photon-counting x-ray CZT detectors have included BMD and luggage security scanning. We have built linear arrays that can advance these applications and be used for higher flux applications like CT. We will report the performance improvements achieved with THM growth of CZT and with the integrated CZT detector subsystems. Conclusions We have improved the performance, price, and availability of CZT detectors for gamma and x-ray imaging applications by transitioning to a THM growth method and by integrating CZT sensors with readout electronics in a detector module that can be easily scaled to different-sized arrays for various medical imaging applications.