Development of MRI-Compatible Nuclear Medicine Imaging Detectors

Abstract

The value of pre-clinical PET and MRI is established, and SPECT also is now routinely used in drug development, disease treatment, and molecular biology research. The aim of this research is to prepare and test imaging prototypes of both SPECT and PET with similar form-factors for use within the core of a pre-clinical MRI. To test the imaging properties of the SPECT detector in a magnetic field a prototype based on CZT semiconductor detectors has been fabricated. This detector has a field-of-view of 2.54 × 12.7 cm 2 and is fitted with a parallel hole collimator for mouse imaging. The prototype is designed to obtain a tomographic dataset by manual positioning within a 90-degree projection range. Shielding, support, positioning, and cooling materials were selected to minimally influence the magnetic field homogeneity. Fabrication of a stationary, polygonal ring of CZT has commenced. An APDbased, light-sharing detector has been evaluated for use in PET. The detector configuration is a 2 × 2 array of 10 mm x 10 mm Hamamatsu S8664-1010 APDs used to read out multi-crystal LYSO blocks. The design of the detector and front-end electronics is optimized for spectroscopic and timing performance, minimization of power dissipation, and low electromagnetic interference. Current plans are for assembling five rings, each with 17 modules, to give a 13.0 cm axial FOV with a 14 cm inner diameter. The results on the tests and performance of both types of modules are reported.

Initial Investigation of Preclinical Integrated SPECT and MR Imaging

“…absorption efficiency ~90% at 140 keV). Wagenaar et al previously reported that this detector yields a high quality pulse height spectrum (PHS) of a 57 Co source (121 keV) in up to a 7 T magnetic field, with an energy resolution (~5%) considerably better than that of scintillation-based detectors in the absence of a magnetic field (6). The high energy resolution of the CZT detector allows for much narrower windowing around the photopeak without losing detection sensitivity, resulting in an improved signal-to-noise ratio (SNR).…”

Design, Performance Evaluation, and Modeling of an Ultrahigh Resolution Detector Dedicated for Simultaneous SPECT/MRI

“…8) with much less computing cost. The spatial resolving power is significantly improved compared to other MRI compatible CZT/CdTe detectors, such as GMI-CZT [33], and scintillator detectors [59] shown in Table. 2.…”

“…Dr. Wagenaar reports a CZT detector for SPECT/MRI applications. The detector has a spatial resolution of about 1.5 mm and an energy resolution of 5% at 122 keV [33]. The feasibility of using this detector for SPECT/MRI application has first been demonstrated by Dr.Hamamura [31].…”

Artificial compound-eye gamma camera for MRI compatible SPECT imaging

“…In 2013, Karel Deprez et al constructed MRI compatible aperture using rapid additive manufacturing with selective laser melting of tungsten powder [10]. Wagenaar et al has reported the design considerations of an MRI compatible SPECT system based on CZT detectors [11]. A prototype of MRI compatible SPECT system developed by the same group has been reported in [12].…”