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The probability of nodal and distant metastasis in patients (pts) with very-low, low, and favorable intermediate risk (FIR) prostate cancer (PCa) is considered low. Current NCCN and AUA/ASTRO guidelines do not recommend PSMA PET staging for these men. However, it has been reported that pts assigned to the FIR category are more likely than low-risk pts to have adverse pathological findings (upstaging and upgrading) at radical prostatectomy (RP) with a trend toward shorter recurrence-free survival. Early detection of clinically significant disease, extraprostatic extension, seminal vesicle invasion, N1 or M1 disease may change medical management in FIR pts and improve treatment outcomes. The purpose of this study is to explore whether piflufolastat F 18 PET/CT or PET/MR can detect higher risk disease in men previously assessed as FIR by standard of care methods. We hypothesize that piflufolastat F 18 PET will detect non-organ confined disease or upgrade pts to International Society of Urologic Pathologists (ISUP) grade ≥3 PCa in at least 5% of FIR subjects. This trial will also assess the ability for PET to better assess the volume and extent of the intraprostatic cancers. MIRROR is a phase 4, open label single arm multicenter study designed to evaluate the diagnostic performance and safety of piflufolastat F 18 in men with newly diagnosed FIR PCa. Eligible male pts must be ≥18 years of age, no prior PCa treatment, have a life expectancy of at least 13 months as determined by investigator, and confirmed FIR PCa per 2023 NCCN guidelines. The date of the prostate biopsy should be no sooner that 2 weeks and no later than 3 months prior to piflufolastat F 18 PSMA PET imaging. Participants will receive a single dose of piflufolastat F 18 injection followed by a single PET/CT or PET/MRI from mid-thigh through skull vertex acquired at 1 to 2 hours post-injection. Pts with a positive study scan results suspicious for PCa ISUP grade ≥3 or non-organ confined disease may be asked to undergo additional diagnostic test(s) for PCa and/or RP with pelvic lymph node dissection within 2 to 90 days after study scan to determine a truth standard. Pts will be monitored for up to 12 months to collect information about PCa treatment decisions and PSA results. The primary objective is to determine the detection rate defined as the proportion of participants with PCa in whom piflufolastat F 18 PET detected intraprostatic ISUP grade ≥3 lesions as confirmed by pathology, or in whom piflufolastat F 18 PET detected the presence of either/or extraprostatic extension, seminal vesicle invasion, regional lymph node involvement, distant metastases. Additional objectives include: change in intended patient clinical management, correct localization rate, true detection rate, sensitivity, specificity, PPV & NPV against reference standard. The study is currently open in the US. NCT06074510 TBD. TBD. [ABSTRACT FROM AUTHOR]

A small-animal positron emission tomography (PET) scanner using PS-APD (position-sensitive avalanche photodiode) detectors has been developed for simultaneous PET/MRI imaging. In this scanner, up to 16 detector modules (one PS-APD per module) are used, and each detector module produces 4 signals to be digitized with their peak values. This leads to as many as 64 analog outputs to the data acquisition (DAQ) system, requiring 64 DAQ channels. In the future, the system will be extended to 32 modules, resulting in 128 channels. It is possible to sample all channels simultaneously, but most of them do not contain useful data, since only one coincidence event (producing data on 8 channels) is identified each time. The purpose of this work was to develop a general-purpose method for reducing the number of analog inputs to the data acquisition for the sparse fast analog signals produced in a PET scanner. To achieve this, a multiplexer board was designed to sample coincidence events from the PET scanner. The effect of the multiplexer on signal quality was evaluated and the average peak-to-valley ratios in detector flood histograms with and without multiplexer were 2.97 and 3.02 respectively. On-board coincidence, pile-up rejection and multiple coincidence rejection functions were implemented and worked as expected. The dead time performance was also characterized. [ABSTRACT FROM AUTHOR]

Purpose: We propose a novel approach for PET respiratory motion correction using tagged-MRI and simultaneous PET-MRI acquisitions.Methods: We use a tagged-MRI acquisition followed by motion tracking in the phase domain to estimate the nonrigid deformation of biological tissues during breathing. In order to accurately estimate motion even in the presence of noise and susceptibility artifacts, we regularize the traditional HARP tracking strategy using a quadratic roughness penalty on neighboring displacement vectors (R-HARP). We then incorporate the motion fields estimated with R-HARP in the system matrix of an MLEM PET reconstruction algorithm formulated both for sinogram and list-mode data representations. This approach allows reconstruction of all detected coincidences in a single image while modeling the effect of motion both in the emission and the attenuation maps. At present, tagged-MRI does not allow estimation of motion in the lungs and our approach is therefore limited to motion correction in soft tissues. Since it is difficult to assess the accuracy of motion correction approaches in vivo, we evaluated the proposed approach in numerical simulations of simultaneous PET-MRI acquisitions using the NCAT phantom. We also assessed its practical feasibility in PET-MRI acquisitions of a small deformable phantom that mimics the complex deformation pattern of a lung that we imaged on a combined PET-MRI brain scanner.Results: Simulations showed that the R-HARP tracking strategy accurately estimated realistic respiratory motion fields for different levels of noise in the tagged-MRI simulation. In simulations of tumors exhibiting increased uptake, contrast estimation was 20% more accurate with motion correction than without. Signal-to-noise ratio (SNR) was more than 100% greater when performing motion-corrected reconstruction which included all counts, compared to when reconstructing only coincidences detected in the first of eight gated frames. These results were confirmed in our proof-of-principle PET-MRI acquisitions, indicating that our motion correction strategy is accurate, practically feasible, and is therefore ready to be tested in vivo.Conclusions: This work shows that PET motion correction using motion fields measured with tagged-MRI in simultaneous PET-MRI acquisitions can be made practical for clinical application and that doing so has the potential to remove motion blur in whole-body PET studies of the torso. [ABSTRACT FROM AUTHOR]