Experimental Evaluation of a 3-D CZT Imaging Spectrometer for Potential Use in Compton-Enhanced PET Imaging

Abstract

We constructed a prototype positron emission tomography (PET) system and experimentally evaluated large-volume 3-D cadmium zinc telluride (CZT) detectors for potential use in Compton-enhanced PET imaging. The CZT spectrometer offers sub-0.5 mm spatial resolution, an ultrahigh energy resolution (~1% @ 511 keV) and the capability of detecting multiple gamma-ray interactions that simultaneously occurred. The system consists of four CZT detector panels with a detection area of around 4.4 cm × 4.4 cm. The distance between the front surfaces of the two opposite CZT detector panels is ~80 mm. This system allows us to detect coincident annihilation photons and Compton interactions inside the detectors and then exploit Compton kinematics to predict the first Compton interaction site and reject chance coincidences. We have developed a numerical integration technique to model the near-field Compton response that incorporates Doppler broadening, detector's finite resolutions, and the distance between the first and second interactions. This method was used to effectively reject random and scattered coincidence events. In the preliminary imaging studies, we have used point-sources, line-sources, a custom-designed resolution phantom and a commercial image quality (IQ) phantom to demonstrate an imaging resolution of approximately 0.75 mm in PET images, and Compton-based enhancement.

State-of-the-art challenges and emerging technologies in radiation detection for nuclear medicine imaging: A review

“…The effective atomic number, density, and bandgap have allowed for room temperature detection while the resistivity is high enough to limit leakage current. Energy resolutions for CZT detectors have been measured to be 1% at 511 keV for different CZT systems [49]. A 40 mm by 40 mm large scale CZT detector has achieved an energy resolution of 1% at 662 keV with a single pixel energy resolution of 0.7% at 662 keV [56].…”

“…Material properties for various semiconductor materials for radiation detection[37,[49][50][51][52][53][54][55].…”

Novel Applications of State-of-the-Art Gamma-Ray Imaging Technique: From Nuclear Decommissioning and Radioprotection to Radiological Characterization and Safeguards

“…MAGING with gamma rays is a powerful technique widely used in nuclear medicine therapy and diagnosis [1]- [3], being able to provide visual information about the distribution of body-injected radioactive elements emitting photons, improving knowledge of the patient status to optimize medical care. The application in non-medical fields, e.g., in the industrial nuclear field (e.g., power plants, research reactors, nuclear fuel fabrication and reprocessing installations, research laboratories, waste management sites), is the natural step to be walked in the development of such technique.…”