Design and system evaluation of a dual-panel portable PET (DP-PET)

Abstract

Background Integrated whole-body PET/MR technology continues to mature and is now extensively used in clinical settings. However, due to the special design architecture, integrated whole-body PET/MR comes with a few inherent limitations. Firstly, whole-body PET/MR lacks sensitivity and resolution for focused organs. Secondly, broader clinical access of integrated PET/MR has been significantly restricted due to its prohibitively high cost. The MR-compatible PET insert is an independent and removable PET scanner which can be placed within an MRI bore. However, the mobility and configurability of all existing MR-compatible PET insert prototypes remain limited. Methods An MR-compatible portable PET insert prototype, dual-panel portable PET (DP-PET), has been developed for simultaneous PET/MR imaging. Using SiPM, digital readout electronics, novel carbon fiber shielding, phase-change cooling, and MRI compatible battery power, DP-PET was designed to achieve high-sensitivity and high-resolution with compatibility with a clinical 3-T MRI scanner. A GPU-based reconstruction method with resolution modeling (RM) has been developed for the DP-PET reconstruction. We evaluated the system performance on PET resolution, sensitivity, image quality, and the PET/MR interference. Results The initial results reveal that the DP-PET prototype worked as expected in the MRI bore and caused minimal compromise to the MRI image quality. The PET performance was measured to show a spatial resolution ≤ 2.5 mm (parallel to the detector panels), maximum sensitivity = 3.6% at the center of FOV, and energy resolution = 12.43%. MR pulsing introduces less than 2% variation to the PET performance measurement results. Conclusions We developed a MR-compatible PET insert prototype and performed several studies to begin to characterize the performance of the proposed DP-PET. The results showed that the proposed DP-PET performed well in the MRI bore and would cause little influence on the MRI images. The Derenzo phantom test showed that the proposed reconstruction method could obtain high-quality images using DP-PET.

Crystal scatter effects in a large-area dual-panel Positron Emission Mammography system

“…However, for a given pie segment, hot rods may have different contrasts and, therefore, this appreciation may be uncertain. To overcome this ambiguity, the calculation of PVR is a well-established quantitative metric used to assess spatial resolution [14,[30][31][32][33].…”

“…A dual-panel PEM is known as a limited-angle tomographic system due to the lack of solid angle coverage for all the lines of response. Because of this lack of complete angle information, filtered backprojection cannot be performed [32,35,36]. In this work, tomographic image reconstruction was carried out with the public domain platform CASToR (Customizable and Advanced Software for Tomographic Reconstruction) using a List-Mode Ordered Subset (LM-OS) Maximum Likelihood Expectation Maximization (ML-EM) iterative algorithm [37].…”

“…Planar sources have been widely used to obtain normalization correction factors for ring scanners [31], for a pair of block detectors [38] and for dual panel PET systems [32,39,40]. In this work, we followed the normalization procedure described in [32] by simulating a planar source of back-to-back 511 keV photons, placed at the middle and parallel to the two detector panels covering the PEM's FOV. The normalization image was calculated in an array of 174×174×24 voxels (each of 1×1×2.5 mm 3 ).…”

DH-Mammo PET: a dual-head positron emission mammography system for breast imaging

“…The existing PEM systems are constructed by the ring (Miyake et al 2014;Li et al 2015;García Hernández et al 2016), rectangle (Wang et al 2006) or dual-head structure (Camarda et al 2006;Luo et al 2010;Neves 2011). The dual-head PET system has an open field of view (FOV), which is convenient to assemble into a multi-modality system, such as PET/Cerenkov-light hybrid system (Yamamoto et al 2014), the dedicated breast PET/CT (Bowen et al 2009), targeted-organ PET/MR (Zeng et al 2021), etc. The dual-head PET system has been applied in clinical studies to guide the breast biopsy (Krishnamoorthy et al 2020) or particle therapy (Ferrero et al 2018).…”