High Energy and Spatial Resolution Small Animal SPECT/CT System

Johns Hopkins University, Baltimore MD

Investigators

Abstract

For this NIH High-End Instrumentation Award application, we propose to acquire a high-performance small animal SPECT/CT system that utilizes state-of-the-art solid-state cadmium zinc telluride (CZT) detectors. The aim of this system is to support ongoing research projects at Johns Hopkins focused on developing novel alpha-emitter radiopharmaceuticals therapy (αRPT). αRPT is an emerging modality in targeted cancer therapy, directly killing cancer cells via DNA double-strand breaks, making it less susceptible to resistance and highly effective for systemic disease treatment. Image-based distribution is crucial for understanding dose response, toxicity, and dosimetry in preclinical studies. Alpha-emitters decay through a complex scheme involving multiple daughters and are potent enough for effective treatment at sub-GBq activity levels. Therefore, accurate quantification of both alpha-emitters and daughters are essential. Currently available small animal SPECT/CT systems, based on scintillator detectors, offer poor energy resolution. We propose acquiring a Scintica High-Resolution SPECT/CT System with CZT detectors, which includes three components: 1) A stationary SPECT system based on the latest 3-D CZT imaging-spectrometer, offering unprecedented energy resolution (<2.5 keV at 140 keV) over the 50-600 keV range, ultrahigh spatial resolution of 0.25 mm in 3-D, and excellent detection sensitivity (2-3%). This system has the best SPECT specifications on the market, providing quick, straightforward anatomical visualization. It has a SPECT FOV diameter of 6 cm with an axial FOV of 9 cm, allowing whole-body spectral imaging to identify all daughter radionuclides. It also supports dynamic SPECT imaging. 2) A high-resolution CT scanner system with 15 μm resolution, a transaxial FOV of 8 cm, and a fixed axial FOV of 12 cm, expandable to 35 cm with dynamic bed movement. The scan acquisition time can be as fast as 15 seconds. 3) State-of-the-art imaging accessories, including a physiological monitoring system for simultaneous temperature control, cardiac and respiratory gating, and an anesthesia system. The high energy resolution of this system will greatly expand the number of radionuclides suitable for medical imaging, serving broader preclinical research needs in oncology, cardiology, and neurology. The operation of the proposed equipment will be overseen by an Advisory Committee composed of the PI, the Co-I, and major users across Johns Hopkins. This committee will meet twice a year to review the system's operation and set policies and procedures to ensure broad use. Additionally, we will hold an annual showcase at the Department of Radiology’s research day to attract potential new users. .