Imaging Capabilities of the Inveon SPECT System Using Single-and Multipinhole Collimators

Abstract

The Inveon small-animal SPECT system comes with several types of multipinhole collimator plates. We evaluate here the performance measurements of the Inveon SPECT system using 6 different collimators: 3 dedicated for mouse imaging and 3 for rat imaging. Methods: The measured performance parameters include the sensitivity, the spatial resolution using line sources, the ultra-micro Derenzo phantom, the recovery coefficient and the noise measurements using the National Electrical Manufacturers Association NU-4 image quality phantom, obtained with the 2 reconstruction algorithms available with the Inveon Acquisition Workplace, version 1.5-the 3-dimensional ordered-subset expectation maximization (3DOSEM) and the 3-dimensional maximum a posteriori (3DMAP). Further, the overall performance of the system is illustrated by an animal experiment. Results: The results show that the Inveon SPECT scanner offers a spatial resolution, measured at the center of the field of view, ranging from 0.6 to 1 mm with the collimator plates dedicated to mouse imaging and from 1.2 to less than 2 mm with rat collimator plates. The system sensitivity varies from 29 to 404 cps/MBq for mouse collimators and from 53 to 175 cps/MBq for rat collimators. The image quality study showed that 3DMAP allows better noise reduction while preserving the recovery coefficient, compared with other regularization strategies such as the premature termination of the 3DOSEM reconstruction or 3DOSEM followed by gaussian filtering. Conclusion: The acquisition parameters, such as the collimator set and the radius of rotation, offer a wide range of possibilities to apply to a large number of biologic studies. However, special care must be taken because this increase in sensitivity can be offset by image degradation, such as image artifacts caused by projection overlap and statistical noise due to a higher number of iterations required for convergence. 3DMAP allowed better noise reduction while maintaining relatively constant recovery coefficients, as compared with other reconstruction strategies. Smal l-animal SPECT systems typically use pinhole collimation, which presents a conical geometry, leading to high magnification and high spatial resolution (1-3). Higher detection efficiency can be obtained using multipinhole collimation (4-9) without theoretically trading the resolution. The Inveon small-animal SPECT system (Siemens Medical Solution) comes with several types of multipinhole collimator plates, which can be mounted on the detector heads. These collimators are designed to rotate at specific radii of rotation (RORs). The combination of the collimator geometric design (number and placement of the pinholes, collimator length, aperture, and degree of multiplexing) and the ROR used fixes many characteristics such as the active field of view (FOV) and the performance of the system in terms of resolution, sensitivity, and resulting reconstruction image quality (IQ). This is different from PET imaging, for which there are no collimation-related parameters to optimiz...

Performance Evaluation of Fifth-Generation Ultra-High-Resolution SPECT System with Two Stationary Detectors and Multi-Pinhole Imaging

“…The results for the 2DT-Scanner in our work are largely consistent with earlier studies on the performance of its established predecessor U-SPECT-II [10]. The tested scanner maintains the characteristic advantages and disadvantages of ultra-high-resolution multi-pinhole SPECT with stationary detectors compared to opponents with moving detectors [3,[21][22][23].…”

Performance Evaluation of Fifth-generation Ultra-high-resolution Spect System With Two Stationary Detectors and Multi-pinhole Imaging

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A Whole-Body Dual-Modality Radionuclide Optical Strategy for Preclinical Imaging of Metastasis and Heterogeneous Treatment Response in Different Microenvironments

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