Unlabelled: As increasing amounts of biomonitoring survey data become available, a new discipline focused on converting such data into estimates of chemical exposures has developed. Reverse dosimetry uses a pharmacokinetic model along with measured biomarker concentrations to determine the plausible exposure concentrations-- a critical step to incorporate ground-truthing experimental data into a distribution of probable exposures that reduces model uncertainty and variability. At the population level, probabilistic reverse dosimetry can utilize a distribution of measured biomarker concentrations to identify the most likely exposure concentrations (or intake doses) experienced by the study participants. PROcEED is software that provides access to probabilistic reverse dosimetry approaches for estimating exposure distributions via a simple user interface.
Availability: PROcEED along with installation instructions is freely available for download from http://www.epa.gov/heasd/products/proceed/proceed.html.
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http://dx.doi.org/10.6026/97320630009707 | DOI Listing |
Mol Imaging Biol
January 2025
Yale PET Center, Yale School of Medicine, New Haven, USA.
Purpose: The sphingosine-1-phosphate receptor-1 (S1PR) is involved in regulating responses to neuroimmune stimuli. There is a need for S1PR-specific radioligands with clinically suitable brain pharmcokinetic properties to complement existing radiotracers. This work evaluated a promising S1PR radiotracer, [F]TZ4877, in nonhuman primates.
View Article and Find Full Text PDFMed Phys
December 2024
Dosimetry for Radiotherapy, Physikalisch-Technische Bundesanstalt, Braunschweig, 38116, Germany.
Background: FLASH radiotherapy is an emerging treatment modality using ultra-high dose rate beams. Much effort has been made to develop suitable dosimeters for reference dosimetry, yet the spatial beam characteristics must also be characterized to enable computerized treatment planning, as well as quality control and service of a treatment delivery device. In conventional radiation therapy, this is commonly achieved by beam profile scans in a water phantom using a point detector.
View Article and Find Full Text PDFPhys Med Biol
December 2024
Physics Division, Department of Radiation Oncology, Massachusetts General Hospital & Harvard Medical School, Boston, MA 02114, United States of America.
TOPAS-nBio enables users to simulate dose rate-dependent radiation chemical yields in water radiolysis accounting for inter-track and long-term chemistry for pulsed irradiation. This study aims to extend the TOPAS-nBio chemistry for the special case of continuous high-dose rate scenario, where both intertrack and longer time reactions need to be considered, and to quantitatively validate the extended framework by comparing the results with experimental data.The inter-track chemistry and escape-values were first evaluated by the independent reaction time method.
View Article and Find Full Text PDFJ Toxicol Environ Health B Crit Rev
February 2025
Risk Sciences International, Ottawa, Canada.
Blood and urine are historically the most frequent matrices used for measuring chemical levels in human biomonitoring studies. As biomonitoring programs are refreshed, consideration of specific priority substances and specific population targets provide opportunities for inclusion of alternative non- or minimally invasive matrices. This review describes methods used in health risk assessment to characterize exposure and risk based upon biomarkers from noninvasive matrices other than urine or blood, including human milk, hair, fingernails, toenails, exhaled breath, deciduous teeth, sweat, semen, meconium, and feces.
View Article and Find Full Text PDFFront Toxicol
October 2024
Division of Toxicology, Office of Applied Research and Safety Assessment, Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, Laurel, MD, United States.
Consumer use of cannabidiol (CBD) is growing, but there are still data gaps regarding its possible adverse effects on reproduction and development. Multiple pathways and signaling cascades involved in organismal development and neuronal function, including endocannabinoid synthesis and signaling systems, are well conserved across phyla, suggesting that can model the effects of exogenous cannabinoids. The effects in on oxidative stress response (OxStrR), developmental timing, juvenile and adult spontaneous locomotor activity, reproductive output, and organismal CBD concentrations were assessed after exposure to purified CBD or a hemp extract suspended in 0.
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