Improving timing resolution of BGO for TOF-PET: a comparative analysis with and without deep learning.

Background: The renewed interest in BGO scintillators for TOF-PET is driven by the improved Cherenkov photon detection with new blue-sensitive SiPMs. However, the slower scintillation light from BGO causes significant time walk with leading edge discrimination (LED), which degrades the coincidence time resolution (CTR). To address this, a time walk correction (TWC) can be done by using the rise time measured with a second threshold.

Antibody-Based PET Imaging of Misfolded Superoxide Dismutase 1 in an Amyotrophic Lateral Sclerosis Mouse Model.

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease characterized by motor neuron loss in the motor cortex, brain stem, and spinal cord. Mutations in the superoxide dismutase 1 (SOD1) gene, resulting in misfolding of its protein product, are a common cause of ALS. Currently, there is no approved ALS diagnostic tool.

On the implementation of acollinearity in PET Monte Carlo simulations.

Acollinearity of annihilation photons (APA) introduces spatial blur in positron emission tomography (PET) imaging. This phenomenon increases proportionally with the scanner diameter and it has been shown to follow a Gaussian distribution. This last statement can be interpreted in two ways: the magnitude of the acollinearity angle, or the angular deviation of annihilation photons from perfect collinearity.

High Tyrosol and Hydroxytyrosol Intake Reduces Arterial Inflammation and Atherosclerotic Lesion Microcalcification in Healthy Older Populations.

Aging is an important risk factor for cardiovascular diseases and convincing data have shown that chronic low-grade inflammation, which develops with advanced age, contributes significantly to cardiovascular risk. The present study aimed to use F-FDG/F-NaF-PET/CT imaging to, respectively, gauge arterial inflammation and microcalcification in a healthy elderly population and to assess the potential benefits of a tyrosol- and hydroxytyrosol-rich diet on these two markers of atherosclerotic plaque fragility. Eleven healthy participants (mean age 75 ± 5.

A ketogenic diet lowers myocardial fatty acid oxidation but does not affect oxygen consumption: a study in overweight humans.

Objective: A ketogenic diet (KD) characterized by very low carbohydrate intake and high fat consumption may simultaneously induce weight loss and be cardioprotective. The "thrifty substrate hypothesis" posits that ketone bodies are more energy efficient compared with other cardiac oxidative substrates such as fatty acids. This work aimed to study whether a KD with presumed increased myocardial ketone body utilization reduces cardiac fatty acid uptake and oxidation, resulting in decreased myocardial oxygen consumption (MVO ).

Timing Estimation and Limits in TOF-PET Detectors Producing Prompt Photons.

The production of prompt photons providing high photon time densities is a promising avenue to reach ultrahigh coincidence time resolution (CTR) in time-of-flight PET. Detectors producing prompt photons are receiving high interest experimentally, ignited by past exploratory theoretical studies that have anchored some guiding principles. Here, we aim to consolidate and extend the foundations for the analytical modeling of prompt generating detectors.

Enhanced Extraction of Blood and Tissue Time-Activity Curves in Cardiac Mouse FDG PET Imaging by Means of Constrained Nonnegative Matrix Factorization.

We propose an enhanced method to accurately retrieve time-activity curves (TACs) of blood and tissue from dynamic 2-deoxy-2-[F]fluoro-D-glucose ([F]FDG) positron emission tomography (PET) cardiac images of mice. The method is noninvasive and consists of using a constrained nonnegative matrix factorization algorithm (CNMF) applied to the matrix () containing the intensity values of the voxels of the left ventricle (LV) PET image. CNMF factorizes into nonnegative matrices and , respectively, representing the physiological factors (blood and tissue) and their associated weights, by minimizing an extended cost function.

Aza-Residue Modulation of Cyclic d,l-α-Peptide Nanotube Assembly with Enhanced Anti-Amyloidogenic Activity.

Transient soluble oligomers of amyloid-β (Aβ) are considered among the most toxic species in Alzheimer's disease (AD). Soluble Aβ oligomers accumulate early prior to insoluble plaque formation and cognitive impairment. The cyclic d,l-α-peptide CP-2 () self-assembles into nanotubes and demonstrates promising anti-amyloidogenic activity likely by a mechanism involving engagement of soluble oligomers.

behavior of [Cu]NOTA-terpyridine platinum, a novel chemo-radio-theranostic agent for imaging, and therapy of colorectal cancer.

To overcome resistance to chemotherapy for colorectal cancer, we propose to validate a novel terpyridine-platinum (TP) compound radiolabeled with the radio-theranostic isotope Cu. stability, biodistribution, PET imaging, tumor growth delay, toxicity and dosimetry of [Cu]NOTA-C3-TP were determined. The current experimental studies show that [Cu]NOTA-C3-TP is stable , rapidly eliminated by the kidneys and has a promising tumor uptake ranging from 1.

Chemical synthesis of fluorinated and iodinated 17β-HSD3 inhibitors and evaluation for imaging prostate cancer tumors and tissue biodistribution.

Prostate cancer is the most common cancer among men and the development of new therapeutic agents is needed for its treatment and/or diagnosis. 17β-hydroxysteroid dehydrogenase type 3 (17β-HSD3) is involved in the production of androgens, which stimulates the proliferation of prostate cancer cells. Piperazinomethyl-androsterone sulfonamide derivatives were developed as 17β-HSD3 inhibitors and the concentration of a representative sulfonamide derivative (compound 1) was found to accumulate in prostate tumor tissues relatively to plasma in a mouse xenograft experiment.

Cu-DOTHA-PSMA, a Novel PSMA PET Radiotracer for Prostate Cancer with a Long Imaging Time Window.

Prostate cancer imaging and late-stage management can be improved with prostate-specific membrane antigen (PSMA)-targeting radiotracers. We developed a PSMA positron emission tomography (PET) radiotracer, DOTHA2-PSMA radiolabeled with 64Cu (T1/2: 12.7 h), to leverage its large imaging time window.

Ga-DOTATATE Prepared from Cyclotron-Produced Ga: An Integrated Solution from Cyclotron Vault to Safety Assessment and Diagnostic Efficacy in Neuroendocrine Cancer Patients.

Cyclotron production of Ga is a promising approach to supply Ga radiopharmaceuticals. To validate this capability, an integrated solution for a robust synthesis of Ga-DOTATATE prepared from cyclotron-produced Ga was achieved. A retrospective comparison analysis was performed on patients who underwent PET/CT imaging after injection of DOTATATE labeled with Ga produced by a cyclotron or eluted from a generator to demonstrate the clinical safety and diagnostic efficacy of the radiopharmaceutical as a routine standard-of-care diagnostic tool in the clinic.

Investigation of a Model-based Time-over-threshold Technique for Phoswich Crystal Discrimination.

The best crystal identification (CI) algorithms proposed so far for phoswich detectors are based on adaptive filtering and pulse shape discrimination (PSD). However, these techniques require free running analog to digital converters, which is no longer possible with the ever increasing pixelization of new detectors. We propose to explore the dual-threshold time-over-threshold (ToT) technique, used to measure events energy and time of occurence, as a more robust solution for crystal identification with broad energy windows in phoswich detectors.

Estimation of the Internal Dose Imparted by F-Fluorodeoxyglucose to Tissues by Using Fricke Dosimetry in a Phantom and Positron Emission Tomography.

Purpose: Assessment of the radiation dose delivered to a tumor and different organs is a major issue when using radiolabelled compounds for diagnostic imaging or endoradiotherapy. The present article reports on a study to correlate the mean F-fluorodeoxyglucose (F-FDG) activity in different tissues measured in a mouse model by positron emission tomography (PET) imaging, with the dose assessed by Fricke dosimetry.

Methods: The dose-response relationship of the Fricke dosimeter and PET data was determined at different times after adding F-FDG (0-80 MBq) to a Fricke solution (1 mM ferrous ammonium sulfate in 0.

Improvement of Spatial Resolution with Iterative PET Reconstruction using UltraFast TOF.

The impact of Time-of-Flight (TOF) on positron emission tomography (PET) spatial resolution is generally considered negligible. In this work, a two-step approach based on simulations of two-dimensional scanner configurations is taken to show that ultra-fast TOF has the potential to overcome the limitation induced by the physical size of detectors on spatial resolution. An estimation of the lower bound on spatial resolution using point sources is provided, followed by a qualitative assessment of the resolution obtained using a Hot Spot phantom.

DeepImageTranslator: A free, user-friendly graphical interface for image translation using deep-learning and its applications in 3D CT image analysis.

The advent of deep-learning has set new standards in an array of image translation applications. At present, the use of these methods often requires computer programming experience. Non-commercial programs with graphical interface usually do not allow users to fully customize their deep-learning pipeline.

A ketogenic supplement improves white matter energy supply and processing speed in mild cognitive impairment.

Introduction: White matter (WM) energy supply is crucial for axonal function and myelin maintenance. An exogenous source of ketones, the brain's alternative fuel to glucose, bypasses the brain's glucose-specific energy deficit and improves cognitive outcomes in mild cognitive impairment (MCI). How an additional supply of ketones affects glucose or ketone uptake in specific WM fascicles in MCI has not previously been reported.

[Ga]Ga-4HMSA a promising new PET tracer for imaging inflammation.

Background: Imaging diagnosis of inflammation has been challenging for many years. Inflammation imaging agents commonly used in nuclear medicine, such as [Ga]Ga-citrate and 2-deoxy-2-[F]fluoro-D-glucose ([F]FDG) showed some limitations. The identification of a radiotracer with high specificity and low radiation dose is clinically important.

Design, Synthesis, and Cytotoxicity Assessment of [Cu]Cu-NOTA-Terpyridine Platinum Conjugate: A Novel Chemoradiotherapeutic Agent with Flexible Linker.

Maximum benefits of chemoradiation therapy with platinum-based compounds are expected if the radiation and the drug are localized simultaneously in cancer cells. To optimize this concomitant effect, we developed the novel chemoradiotherapeutic agent [Cu]Cu-NOTA-C3-TP by conjugating, via a short flexible alkyl chain spacer (C3), a terpyridine platinum (TP) moiety to a NOTA chelator complexed with copper-64 (Cu). The decay of Cu produces numerous low-energy electrons, enabling the Cu-conjugate to deliver radiation energy close to TP, which intercalates into G-quadruplex DNA.

The regional effect of serum hormone levels on cerebral blood flow in healthy nonpregnant women.

Sex hormones estrogen (EST) and progesterone (PROG) have received increased attention for their important physiological action outside of reproduction. While studies have shown that EST and PROG have significant impacts on brain function, their impact on the cerebrovascular system in humans remains largely unknown. To address this, we used a multi-modal magnetic resonance imaging (MRI) approach to investigate the link between serum hormones in the follicular phase and luteal phase of the menstrual cycle (MC) with measures of cerebrovascular function (cerebral blood flow [CBF]) and structure (intracranial artery diameter).