Active and passive dosimetry for beta-emitting radiopharmaceutical therapy agents in a custom SPECT/CT compatible phantom.

. This work introduces a novel approach to performing active and passive dosimetry for beta-emitting radionuclides in solution using common dosimeters. The measurements are compared to absorbed dose to water () estimates from Monte Carlo (MC) simulations.

In-vivo inhibition of neutral endopeptidase 1 results in higher absorbed tumor doses of [Lu]Lu-PP-F11N in humans: the lumed phase 0b study.

Background: A new generation of radiolabeled minigastrin analogs delivers low radiation doses to kidneys and are considered relatively stable due to less enzymatic degradation. Nevertheless, relatively low tumor radiation doses in patients indicate limited stability in humans. We aimed at evaluating the effect of sacubitril, an inhibitor of the neutral endopeptidase 1, on the stability and absorbed doses to tumors and organs by the cholecystokinin-2 receptor agonist [Lu]Lu-PP-F11N in patients.

A physics based machine learning model to characterize room temperature semiconductor detectors in 3D.

Room temperature semiconductor radiation detectors (RTSD) for X-ray and -ray detection are vital tools for medical imaging, astrophysics and other applications. CdZnTe (CZT) has been the main RTSD for more than three decades with desired detection properties. In a typical pixelated configuration, CZT have electrodes on opposite ends.

Identifying Defects without Knowledge in a Room-Temperature Semiconductor Detector Using Physics Inspired Machine Learning Model.

Room-temperature semiconductor radiation detectors (RTSD) such as CdZnTe are popular in Computed Tomography (CT) imaging and other applications. Transport properties and material defects with respect to electron and hole transport often need to be characterized, which is a labor intensive process. However, these defects often vary from one RTSD to another and are not known during characterization of the material.

Exploring the Limitations of Hybrid Adiabatic Quantum Computing for Emission Tomography Reconstruction.

Our study explores the feasibility of quantum computing in emission tomography reconstruction, addressing a noisy ill-conditioned inverse problem. In current clinical practice, this is typically solved by iterative methods minimizing a L2 norm. After reviewing quantum computing principles, we propose the use of a commercially available quantum annealer and employ corresponding hybrid solvers, which combine quantum and classical computing to handle more significant problems.

Myocardial perfusion imaging with retrospective gating and integrated correction of attenuation, scatter, respiration, motion, and arrhythmia.

Background: Absolute quantitative myocardial perfusion SPECT requires addressing of aleatory and epistemic uncertainties in conjunction with providing image quality sufficient for lesion detection and characterization. Iterative reconstruction methods enable the mitigation of the root causes of image degradation. This study aimed to determine the feasibility of a new SPECT/CT method with integrated corrections attempting to enable absolute quantitative cardiac imaging (xSPECT Cardiac; xSC).

eQTL Catalogue 2023: New datasets, X chromosome QTLs, and improved detection and visualisation of transcript-level QTLs.

The eQTL Catalogue is an open database of uniformly processed human molecular quantitative trait loci (QTLs). We are continuously updating the resource to further increase its utility for interpreting genetic associations with complex traits. Over the past two years, we have increased the number of uniformly processed studies from 21 to 31 and added X chromosome QTLs for 19 compatible studies.

Method for comparison of data driven gating algorithms in emission tomography.

Multiple algorithms have been proposed for data driven gating (DDG) in single photon emission computed tomography (SPECT) and have successfully been applied to myocardial perfusion imaging (MPI). Application of DDG to acquisition types other than SPECT MPI has not been demonstrated so far, as limitations and pitfalls of current methods are unknown.We create a comprehensive set of phantoms simulating the influence of different motion artifacts, view angles, moving objects, contrast, and count levels in SPECT.

3D-Quantitated Single Photon Emission Computed Tomography/Computed Tomography: Impact on intended Management Compared to Lung Perfusion Scan in Marginal Candidates for Pulmonary Resection.

Objectives: Based on previous studies, single-photon emission computed tomography/computed tomography (SPECT/CT) has been proven more accurate and reproducible than planar lung perfusion scintigraphy to assess lobar perfusion. However, the impact of 3D-quantitated SPECT/CT on intended management in functionally marginal candidates for pulmonary resection is unknown. The evaluation of this impact was the main aim of this study.

Validation of Monte Carlo simulated absorbed-dose-to-water inside a custom SPECT/CT phantom using active and passive dosimeters: a feasibility study usingTc.

.This project aims to provide a novel method for performing dosimetry measurements on TRT radionuclides using a custom-made SPECT/CT compatible phantom, common active and passive detectors, and Monte Carlo simulations. In this work we present a feasibility study usingTc for a novel approach to obtaining reproducible measurements of absorbed-dose-to-water from radionuclide solutions using active and passive detectors in a custom phantom for the purpose of benchmarking Monte Carlo-based absorbed-dose-to-water estimates.

Learning-based physical models of room-temperature semiconductor detectors with reduced data.

Room-temperature semiconductor radiation detectors (RTSD) have broad applications in medical imaging, homeland security, astrophysics and others. RTSDs such as CdZnTe, CdTe are often pixelated, and characterization of these detectors at micron level can benefit 3-D event reconstruction at sub-pixel level. Material defects alongwith electron and hole charge transport properties need to be characterized which requires several experimental setups and is labor intensive.

A successful salvage story: Uveitis with nontuberculous mycobacterial infection in a patient on secukinumab.

The reported occurrence of ocular infections with nontuberculous mycobacterial (NTM) infections has been increasing in the past few decades. NTM are known to cause intraocular infections as well as infections of the ocular appendages and are often recalcitrant to medical therapy. Uveal involvement due to NTM is rare and most reported cases have predisposing factors such as cataract surgery or immunocompromised states.

A Prospective Comparative Study of Using Ultrasonography, 4D-CT and Parathyroid Dual-Phase Scintigraphy with SPECT in Patients with Primary Hyperparathyroidism.

Thirty-one consecutive patients were included in this study who were planned for parathyroidectomy due to primary hyperparathyroidism. They were studied with US, 4D-CT and dual-phase scintigraphy including SPECT/CT, and possible adenomas were identified in each imaging modality. Imaging data were quantified with US, CT and SPECT.

Cholecystokinin 2 Receptor Agonist Lu-PP-F11N for Radionuclide Therapy of Medullary Thyroid Carcinoma: Results of the Lumed Phase 0a Study.

Treatment of patients with advanced medullary thyroid carcinoma (MTC) is still a challenge. For more than 2 decades, it has been known that the cholecystokinin 2 receptor is a promising target for the treatment of MTC with radiolabeled minigastrin analogs. Unfortunately, kidney toxicity has precluded their therapeutic application so far.

ROC study and SUV threshold using quantitative multi-modal SPECT for bone imaging.

Background: We investigated the clinical performance of a quantitative multi-modal SPECT/CT reconstruction platform for yielding radioactivity concentrations of bone imaging with Tc-methylene diphosphonate (MDP) or Tc-dicarboxypropane diphosphonate (DPD). The novel reconstruction incorporates CT-derived tissue information while preserving the delineation of tissue boundaries. We assessed image-based reader concordance and confidence, and determined lesion classification and SUV thresholds from ROC analysis.

IQ·SPECT technology and its clinical applications using multicenter normal databases.

IQ·SPECT (Siemens Medical Solutions) is a solution for high-sensitivity and short-time acquisition imaging of the heart for a variable angle general purpose gamma camera. It consists of a multi-focal collimator, a cardio-centric orbit and advanced iterative reconstruction, modeling the image formation physics accurately. The multi-focal collimator enables distance-dependent enlargement of the center region while avoiding truncation at the edges.

Fully Automated Data-Driven Respiratory Signal Extraction From SPECT Images Using Laplacian Eigenmaps.

We propose a data-driven method for extracting a respiratory surrogate signal from SPECT list-mode data. The approach is based on dimensionality reduction with Laplacian Eigenmaps. By setting a scale parameter adaptively and adding a series of post-processing steps to correct polarity and normalization between projections, we enable fully-automatic operation and deliver a respiratory surrogate signal for the entire SPECT acquisition.

Dose reduction in half-time myocardial perfusion SPECT-CT with multifocal collimation.

Background: Recent technological advances in myocardial perfusion imaging may warrant the use of lower injected activity. We evaluated whether quantitative measures of stress myocardial perfusion defects using Tc-99m sestamibi and low-energy high-resolution (LEHR) collimators are equivalent to lower dose SPECT-CT with cardiac multifocal collimators and software (IQ·SPECT).

Methods: 93 patients underwent one-day rest-stress gated SPECT-CT.

Beyond current guidelines: reduction in minimum administered radiopharmaceutical activity with preserved diagnostic image quality in pediatric hepatobiliary scintigraphy.

Purpose: To determine if the minimum administered radiopharmaceutical activity for hepatobiliary scintigraphy can be reduced while preserving diagnostic image quality using enhanced planar processing (EPP).

Methods: A total of 40 infants between 10 and 270 days old (body mass 2.2 - 6.

Quantification of 99mTc-DPD concentration in the lumbar spine with SPECT/CT.

Background: Routine single-photon emission computed tomography (SPECT) currently lacks quantitative information on regional activity concentration (ACC) of the injected tracer (e.g. kBq/ml).

Reduction in radiation dose in mercaptoacetyltriglycerine renography with enhanced planar processing.

Purpose: To determine the minimum dose of technetium 99m ((99m)Tc) mercaptoacetyltriglycerine (MAG3) needed to perform dynamic renal scintigraphy in the pediatric population without loss of diagnostic quality or accurate quantification of renal function and to investigate whether adaptive noise reduction could help further reduce the minimum dose required.

Materials And Methods: Approval for this retrospective study was obtained from the institutional review board, with waiver of informed consent. A retrospective review was conducted in 33 pediatric patients consecutively referred for a (99m)Tc-MAG3 study.

Pediatric 99mTc-MDP bone SPECT with ordered subset expectation maximization iterative reconstruction with isotropic 3D resolution recovery.

Purpose: To perform a preliminary evaluation of the image quality of pediatric technetium 99m ((99m)Tc) methylene diphosphonate (MDP) bone single photon emission computed tomography (SPECT) by using iterative reconstruction-ordered subset expectation maximization with three-dimensional resolution recovery (OSEM-3D)-and to assess whether any improvements with use of this technique could lead to a reduction in patient dose or a shortening in imaging time.

Materials And Methods: Institutional advisory board approval was obtained for this investigation. Fifty (99m)Tc-MDP SPECT studies of the spine were evaluated (36 female and 14 male patients; mean age, 15.

Quantitative accuracy of clinical 99mTc SPECT/CT using ordered-subset expectation maximization with 3-dimensional resolution recovery, attenuation, and scatter correction.

Unlabelled: We present a calibration method of a clinical SPECT/CT device for quantitative (99m)Tc SPECT. We use a commercially available reconstruction package including ordered-subset expectation maximization (OSEM) with depth-dependent 3-dimensional resolution recovery (OSEM-3D), CT-based attenuation correction, and scatter correction. We validated the method in phantom studies and applied it to images from patients injected with (99m)Tc-diphosponate.