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In September 2021, National Comprehensive Cancer Network (NCCN) Guidelines were updated to allow prostate specific membrane antigen (PSMA) PET staging for newly diagnosed unfavorable intermediate-risk (UIR), high-risk (HR), or very high-risk (VHR) prostate cancer. Subsequent uptake of staging PSMA PET and positivity rates are unknown. We identified all newly diagnosed prostate cancer cases in the national Veterans Health Administration (VHA) from January 2020 to August 2023. Staging PSMA scans within +/- 90 days of prostate cancer diagnosis were identified using VHA radiology data and linked records from non-VHA providers. Gleason score (GS) was identified by a validated natural language processing algorithm. Initial PSA and TNM stage were collected through VHA electronic medical record data; missing stage variables were imputed. The proportion of patients undergoing PSMA staging over time was quantified by GS and PSA. We performed manual chart review of 2,024 staging PSMA scan reports performed within VHA to assess PSMA positivity rates by NCCN risk group defined by conventional imaging. We identified 35,440 patients with newly diagnosed prostate cancer, of whom 4,562 underwent PSMA staging. Median age was 69; 56% identified as White and 36% Black. The proportion of patients undergoing PSMA staging began increasing in all groups in early 2021 and continued to increase through the end of the study period. In the last 6 months of the study period (2/2023 to 8/2023), the proportion of patients with PSMA staging by GS/PSA was 3.1% (GS6, PSA<10), 16.0% (GS6, PSA 10-20 or GS3+4, PSA<10), 45.6% (GS4+3, PSA<20 or GS 3+4, PSA 10-20), 60.9% (GS 8-10 or PSA>20), and 66.1% (GS 8-10 and PSA>20). Among patients who were N0/M0 by conventional imaging, PSMA positivity rates (N1 and/or M1) were 0% (0/17, low risk [LR]), 1.5% (3/195, favorable intermediate risk [FIR]), 4.0% (20/490, UIR), 11% (76/690, HR), and 29% (106/370, VHR). Rates of nodal disease only (PSMA N1/M0) were 1.5% in FIR, 1.0% in UIR, 7.1% in HR, and 12.2% in VHR. Rates of oligometastatic disease (1-5 PSMA positive distant metastases, with or without nodal disease) were 0% in FIR, 2.7% in UIR, 2.9% in HR, and 9.7% in VHR. Rates of widespread metastases (>10 PSMA metastases) were 0% in FIR, 0% in UIR, 0.1% in HR, and 3.3% in VHR. Rates of PSMA staging for newly diagnosed prostate cancer increased from 2020-2023 in the VHA, including among patients meeting FIR criteria by GS and PSA. Overall nodal or distant positivity rates among FIR and UIR patients were low (<5%). Optimal resource allocation may require reconsideration of routine PSMA staging for all UIR patients and efforts to decrease PSMA staging for FIR patients. [ABSTRACT FROM AUTHOR]

Despite the acknowledged advantages of CsI:T1 for most scintillator applications, its use for CT and other high-speed imaging has been hindered by a high degree of afterglow in its scintillation decay. We have found that a particularly effective way to suppress this afterglow is to codope the material with certain dipositive rare earth ions capable of trapping the vagrant carriers that give rise to it, We have extensively studied the manner in which one such ion, [Eu.sup.2+], alters the spectroscopic and kinetic properties of the scintillation, and have developed a coherent mathematical model consistent with the experimental results. But the beneficial effect of [Eu.sup.2+] appears to be restricted only to relatively short times (say [less than or equal to] 200 ms) after the end of the excitation pulse. To be effective at longer times, the codopant should also provide some nonradiative means to annihilate the trapped carriers before their escape can enhance the low-level long-term emission. And, as predicted by the model, this is exactly what [Sm.sup.2+] does. In this paper we describe the experimental effort to characterize the behavior of the CsI:T1,Sm material system. Spectroscopically, we find that the familiar broad TI emission becomes distorted and progressively shifted to shorter wavelengths. Kinetically, we find that the afterglow of the emission is substantially reduced relative to conventional CsI:T1 (no codopant), and that this effect is always found, regardless of the conditions of excitation. And finally, we find that the material shows virtually no memory of its previous excitation history (the so-called hysteresis phenomenon), in stark contrast with both conventional CsI:T1 and the corresponding material codoped with Eu. Various aspects of these effects and their dependence on the concentrations of the dopants are also discussed. Index Terms--Afterglow suppression, cesium iodide, rapid imaging, scintillation kinetics.

Although LSO is one of the most successful scintillator developments for medical diagnostics in the last two decades, good single crystals are not commercially available in any quantity. Consequently, we explored the feasibility of developing a ceramic version of the material, which requires a considerably lower temperature to consolidate the material to essentially crystalline density. Consolidation of the ceramic was achieved by hot pressing at temperatures up to 1700C and pressure of 8000 psi. Hot pressing causes a loss of oxygen resulting in strong coloration of the ceramic, which had to be removed by heating ('bleaching') in air at approximately 1100C. The resultant specimens were colorless and highly translucent, but the anisotropic nature of the crystal structure precluded the achievement of full transparency. The scintillation performance of the resulting ceramics was characterized and compared with that of high light-output LSO single crystals. The scintillation efficiency as measured by energy spectra generally fell in the range of 50-60% of that of the crystals. While this would be adequate for PET applications, the limited transparency provides a barrier to such use. An alternative application would be in signal integrating techniques, such as CT, where it could provide an alternative to GOS but with higher speed. Here, the problem of afterglow assumes major importance. The afterglow is a function of many factors, including conditions of excitation. Further work on improving the LSO ceramics is considered. Index Terms--Afterglow, ceramic scintillators, efficiency, LSO, transparency.

The authors report a new scintillator based on a transparent ceramic of [Lu.sub.2][O.sub.3]: Eu. The material has an extremely high density of 9.4 g/[cm.sup.3] and a light output comparable to CsI:TI. Its narrow-band emission at 610 nm perfectly matches the spectral response of charge coupled devices (CCDs). To enhance the spatial and contrast resolution, the authors have developed a special process to pixelate the scintillator and prevent the spread of light within the scintillator volume. The imaging performance of this pixelated device was evaluated using a thermoelectrically cooled CCD camera. The new scintillator is expected to play a major role in digital radiographic systems when readout technologies capable of taking advantage of the transparency are developed further. Index Terms--Digital radiography, scintillators.

We report here on a high-speed X-ray imaging camera, specifically developed for time resolved diffraction studies using synchrotron and laboratory X-ray sources. This camera is capable of acquiring six X-ray images at speeds of up to 2300 frames per second (f/s). The system is based on a modified architecture charge coupled device (CCD) optically coupled to a fiber-optic taper via an image intensifier. The front end of the taper is coupled to a specially designed microstructured CsI(Tl) scintillator screen capable of providing high light output, very high-detection efficiency, and excellent spatial resolution. In addition to the time resolved diffraction studies, this detector will be extremely valuable in applications such as dynamic imaging of small animals, X-ray microtomography, and materials science applications. This paper discusses the design and performance characterization of the imaging system. Additionally, we present some preliminary high-speed X-ray imaging data obtained using laboratory X-ray sources. Index Terms--High-speed X-ray imaging, image sensors, structured CsI, X-ray diffraction.

New third generation x-ray sources such as the Advanced Photon Source have created a need for a detector that can provide multiple frames of detailed x-ray images on the millisecond time scale. Such detectors will prove invaluable in applications such as time-resolved x-ray diffraction, x-ray microtomography, as well as materials science applications like polymer processing. Currently, detectors capable of acquiring high resolution x-ray images at such high speed do not exist, thus limiting progress in many of these important areas of research. To address these needs we have developed a prototype fast x-ray imaging system, using a structured CsI(Tl) scintillator coupled to a fast-frame 1K x 1K CCD. The system has been successfully employed to capture 1024 x 64 pixel x-ray images at a rate of 1000 frames per second (fps) with a 12 bit dynamic range. The system exceeds the capabilities of the current high speed x-ray imaging systems which typically operate at the rate of 30 fps. Fabrication of a large area detector is currently underway, using a microstructured CsI(Tl) scintillator coupled to a fast-frame CCD with a 3:1 fiberoptic taper. The camera will operate in a burst mode, acquiring 8 1K x 1K images at rates up to 1000 frames per second with 12 bit dynamic range. Higher image capture speeds can be accomplished by reducing the image area. This paper will discuss the specific characteristics of the CsI(Tl) screens, experimental details of the prototype and the new design for the large area detector being developed specifically for time-resolved x-ray diffraction experiments in structural biology.

We are developing large-area, thick, structured CsI(T1) imaging sensors for a wide variety of X-ray imaging applications. Recently we have fabricated structured CsI(T1) scintillators ranging from 30 [[micro]meter] (16 mg/[cm.sup.2]) to 2000 [[micro]meter] (900 mg/[cm.sup.2]) in thickness and up to 15 x 15 [cm.sup.2] in area. Even 2000-[[micro]meter]-thick film showed well-controlled columnar growth throughout the film. Material characterization confirmed that the film is crystalline in nature and that the stoichiometry is preserved. To improve the spatial resolution of thick films, post-deposition treatments were performed. The effect of these treatments on film characteristics was quantitatively evaluated by measuring signal output, modulation transfer function [MTF(f)], noise power spectrum [NPS(f)], and detective quantum efficiency [DQE(f)]. The data show that by proper film treatments, the film DQE(f) can be improved.