H3D (United States)

Targeted alpha therapy with <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">225</sup>Ac is a promising modality for cancer treatment, as recently shown in pre-clinical and clinical trials. Achieving a precise understanding of the biokinetics of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">225</sup>Ac radiopharmaceuticals is critical to leverage their potential in the clinic. Although this is typically achieved via gamma-ray imaging experiments, such imaging is very challenging for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">225</sup>Ac due to the extremely low injected activities (<37 kBq), the unfavorable gamma-ray branching ratios (<26%), and the complicated decay chain. Standard SPECT with collimation struggles to achieve quality images and accurate quantification in pre-clinical experiments. In this work, we propose Compton imaging as an alternative solution for this problem. We leverage a commercial CZT Compton camera to achieve in-vivo imaging of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">225</sup>Ac in mice at therapeutic activities below the microcurie. We compared the sensitivity of a single-head Compton imaging system with that of a standard collimated gamma camera to be 4.7 times greater for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">213</sup>Bi and 7.5 for <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">221</sup>Fr. We successfully imaged <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">225</sup>Ac daughter biodistributions of <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">221</sup>Fr and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">213</sup>Bi in a mouse in vivo with only 30 minutes scan time and a single bed position. Performance can be further improved by using more detector heads and via system optimization. Comparison between in-vivo and ex-vivo will be presented and discussed.

3D CdZnTe detector modules can be tiled in tight-packed arrays to provide high efficiency in a compact form factor. In this work, the effect of neighboring modules on the CdZnTe detector response was investigated for an array with sub-millimeter spacing between modules.Measurements and simulations show that the air gap between detectors is small enough that both the cathode and anode weighting potentials are affected by the presence of neighboring modules. For regions of the detector near neighbor modules, the cathode weighting potential becomes nonlinear and the anode weighting potential improves in the near-anode region.

Historically, Compton imagers have primarily been operated as stationary imagers. Recent advances in sensors and computing have enabled imagers to move while collecting measurements, enabling the mapping of gamma-ray radiation onto 3D surfaces and volumes. However, traditional Compton imaging methods do not directly generalize to 3D space due to computational complexity and varying sensitivity of the detector. This study builds on previous 3D imaging algorithms for a method applicable to the range of source distributions from point sources to broad distributed sources. Specifically, we propose a maximum-likelihood method iteratively adding point sources or regions of fully voxelized estimates until the measured events are best explained. Furthermore, we describe validation measurements using 500 point sources of Cu-64 to emulate a broadly distributed source and lessons learned for these algorithms.

Pixelated CdZnTe gamma-ray detectors have proven to be versatile tools for characterization of radiation fields in unknown spaces. This is due in part to their fine spatial resolution, allowing for high fidelity radiation images. The position of radiation interactions can be determined to subpixel precision by analyzing non-collecting pixel signals. Recent electronics allow for the recording of full event waveforms from these non-collecting pixels, offering an improvement in position resolution compared to traditional analog processing electronic chains. However, the relationship between signal waveform and subpixel position is complicated and it is challenging to design an algorithm that makes the best use of the available information to reconstruct the position. We demonstrate a position reconstruction technique based on principal component analysis of the signal waveforms. A calibration method is presented and discussed, and an improvement over the traditional neighbor-ratio based techniques is demonstrated in experiment using a Cs-137 source. The position resolution with a coarse-level implementation is improved by 25 µm relative to the classic techniques.

Skilled nursing facility (SNF) care is frequently used after cardiac surgery, but the patterns and determinants of use have not been well understood. The objective of this study was to evaluate determinants and outcomes associated with SNF use after isolated coronary artery bypass grafting. A retrospective analysis of Medicare Fee-For-Service claims linked to the Society of Thoracic Surgeons clinical data was conducted on isolated coronary artery bypass grafting patients without prior SNF use in Michigan between 2011 and 2019. Descriptive analysis evaluated the frequency, trends, and variation in SNF use across 33 Michigan hospitals. Multivariable mixed-effects regression was used to evaluate patient-level demographic and clinical determinants of SNF use and its effect on short- and long-term outcomes. In our sample of 8614 patients, the average age was 73.3 years, 70.5% were male, and 7.7% were listed as non-White race. An SNF was utilized by 1920 (22.3%) patients within 90 days of discharge and varied from 3.2% to 58.3% across the 33 hospitals. Patients using SNFs were more likely to be female, older, non-White, with more comorbidities, worse cardiovascular function, a perioperative morbidity, and longer hospital lengths of stay. Outcomes were significantly worse for SNF users, including more frequent 90-day readmissions and emergency department visits and less use of home health and rehabilitation services. SNF users had higher risk-adjusted hazard of mortality (hazard ratio, 1.41 [95% CI, 1.26-1.57]; P<0.001) compared with non-SNF users and had 2.7-percentage point higher 5-year mortality rate in a propensity-matched cohort of patients (18.1% versus 15.4%; P<0.001). The use of SNF care after isolated coronary artery bypass grafting was frequent and variable across Michigan hospitals and associated with worse risk-adjusted outcomes. Standardization of criteria for SNF use may reduce variability among hospitals and ensure appropriateness of use.

Several tests have been performed with an H420 pixelated CdZnTe imaging spectrometer to evaluate its capability to provide reliable imaging and quantification results. Waste barrels prepared by National Physical Laboratory (NPL) for the Nuclear Industry Proficiency Test Exercise held in 2019 and 2021 were measured, detecting clear <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">241</sup> Am, <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs, and <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">60</sup> Co photopeaks in collected gamma-ray spectra, while Compton and coded aperture imaging were used to localize sources and reconstruct their 2D/3D spatial distributions. Point-kernel-based activity quantification techniques were used to estimate isotope-specific activities, with results close to those obtained by High Purity Germanium detectors and to true NPL declarations. Furthermore, in order to test the reliability of the quantification method for a large span of energies/distances/materials, a hot <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">226</sup> Ra source was measured in multiple geometries, obtaining consistent data, although difficulties in measuring peak areas on large, non-linear continua were observed. The results presented in this work suggests that high-resolution 3D pixelated CdZnTe detectors can be used for typical waste quantification problems and can reliably assay complex geometries thanks to flexibility of the quantification algorithm. Moreover, the spatial information on the radionuclides’ distribution from gamma-ray imaging can be used as input for a heterogeneous radioactivity model to minimize systematic uncertainties.

High-dose-rate operation of 3D pixelated CdZnTe detectors is complicated by high chance-coincidence rates. Spectra are contaminated by large, chance-coincidence features that reduce photopeak-to-continuum ratios. Compton images, which are formed by true, multiple interaction events, are contaminated by chance-coincidence events. New spectral and Compton imaging techniques, leveraging the intrinsic, 3D nature of pixelated readout, were developed to mitigate the impact of chance-coincidence events at high dose rates. Chance-coincidence mitigation techniques were tested on an H3D, Inc. M400 CdZnTe detector at dose rates exceeding 1 R/h using a <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">137</sup> Cs irradiator. Spectral rejection of chance-coincidence events, as measured by photopeak-to-continuum ratios, was observed by binning events on a by-interaction basis. Compton image quality was improved by preferentially selecting events with small lever arms.

Background:Preexisting cardiovascular disease (CVD) is perceived as a risk factor for poor outcomes in patients with COVID-19. We sought to determine whether CVD is associated with in-hospital death and cardiovascular events in critically ill patients with COVID-19.Methods:This study used data from a multicenter cohort of adults with laboratory-confirmed COVID-19 admitted to intensive care units at 68 centers across the United States from March 1 to July 1, 2020. The primary exposure was CVD, defined as preexisting coronary artery disease, congestive heart failure, or atrial fibrillation/flutter. Myocardial injury on intensive care unit admission defined as a troponin I or T level above the 99th percentile upper reference limit of normal was a secondary exposure. The primary outcome was 28-day in-hospital mortality. Secondary outcomes included cardiovascular events (cardiac arrest, new-onset arrhythmias, new-onset heart failure, myocarditis, pericarditis, or stroke) within 14 days.Results:Among 5133 patients (3231 male [62.9%]; mean age 61 years [SD, 15]), 1174 (22.9%) had preexisting CVD. A total of 1178 (34.6%) died, and 920 (17.9%) had a cardiovascular event. After adjusting for age, sex, race, body mass index, history of smoking, and comorbidities, preexisting CVD was associated with a 1.15 (95% CI, 0.98–1.34) higher odds of death. No independent association was observed between preexisting CVD and cardiovascular events. Myocardial injury on intensive care unit admission was associated with higher odds of death (adjusted odds ratio, 1.93 [95% CI, 1.61–2.31]) and cardiovascular events (adjusted odds ratio, 1.82 [95% CI, 1.47–2.24]), regardless of the presence of CVD.Conclusions:CVD risk factors, rather than CVD itself, were the major contributors to outcomes in critically ill patients with COVID-19. The occurrence of myocardial injury, regardless of CVD, and its association with outcomes suggests it is likely due to multiorgan injury related to acute inflammation rather than exacerbation of preexisting CVD.Registration:NCT04343898; https://clinicaltrials.gov/ct2/show/NCT04343898.

Large-volume 3D-position-sensitive CdZnTe is used in many applications for spectroscopy and Compton imaging. Being able to determine the incident gamma-ray flux, as a function of both the energy and direction, is, of course, a useful feature to provide more information from each measurement. Deconvolution in the energy domain should be able to identify emission lines and continuous distributions over energy. Deconvolution in the direction domain should be able to identify point sources and distributed sources. In this work, a hybrid deconvolution method is introduced, which uses the image to improve the spectral deconvolution and the spectrum to improve the image deconvolution, while still being fast enough to run on practical problems. Details of the deconvolution method are presented along with representative results.

Sale and Purchase of Local Wisdom Based Wisdom (Study of Luat Lombang Village, Sipirok District) This article reviews the models of auction buying and selling in Luat Lombang Village community. For these people, buying and selling auction is no longer seen solely as a provision determined by religion, but has become a habit and need in community life.&#x0D; The approach method used in this article is the empirical juridical approach method, namely research on the effectiveness of law by studying legal regulations which are then linked to data and behavior that lives and develops in the midst of society.&#x0D; So the results of the study show that: First, the factors still carrying out the sale and purchase of auctions in the community of Luat Lombang Village, Sipirok District, because it has become a custom. Second, the sale and purchase of auctions to the public is done in cash, real and clear. Third, the legality of the implementation of buying and selling based on Islamic law in the community of Luat Lombang Village, Sipirok Subdistrict, is legal because it has fulfilled the legal requirements for the sale and purchase agreement and there are benefits for the buyer and the whole community can benefit from the sale of the auction.