For medium energy x-rays produced with tube voltages from 70 to 280 kV, the absorbed dose to water, D(w), has been determined by means of water calorimetry with relative standard uncertainties ranging from 0.45% to 0.98% at 280 and 70 kV. The results were confirmed by Monte Carlo calculations, in which the ratios of D(w) at 5 cm depth in a reference water phantom to the air kerma free in air, K(a), at the same point in space were compared to the corresponding ratios determined experimentally. The general agreement between measurement and calculation was better than 1%. These results confirm earlier investigations in which the absorbed dose to graphite was determined by means of a graphite extrapolation chamber. For the Monte Carlo calculations, an attempt was made to present a complete uncertainty budget, taking into account type B contributions also.
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http://dx.doi.org/10.1088/0031-9155/57/19/6245 | DOI Listing |
Phys Eng Sci Med
January 2025
Department of Physics and Radiation Safety, Nepean Hospital, Penrith, New South Wales, Australia.
The radiation exposure to bystanders from nuclear medicine patients is a common concern raised in nuclear medicine departments. The GATE (Geant4 Application for Tomographic Emission) Monte Carlo radiation transport application was used to estimate the dose to a bystander. Two voxelised phantoms were utilised in a GATE Monte Carlo simulation as the radiation source and target.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Clinical Microbiology and Infectious Diseases, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Background: Oritavancin (ORT) is a new single-dose lipoglycopeptide showing activity against staphylococci and vancomycin-resistant enterococci. However, there is no data regarding its potential use as a catheter lock solution are scarce. We constructed an model to analyze the efficacy and stability of an ORT lock solution against the biofilm of staphylococci and enterococci over 7 days at 37 °C.
View Article and Find Full Text PDFF1000Res
January 2025
Departments of Psychiatry, Neurology, Radiology, and Neuroscience, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA.
Reddy and Reddy (2014) discuss the optimal timing for lithium levels in patients taking once-daily extended-release lithium formulations. They argue for blood sampling 24 h after the previous dose rather than the standard 12 h. I interpret the data quite differently.
View Article and Find Full Text PDFClin Pharmacol Ther
January 2025
Division of Applied Regulatory Science, Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food & Drug Administration, Silver Spring, Maryland, USA.
In response to increased illicit use of synthetic opioids, various μ-receptor antagonist formulations, with varied pharmacological characteristics, have been and are being developed. To understand how pharmacologic characteristics such as absorption rate and clearance rate affect reversal in treating community opioid overdose, we used our previously published translational opioid model. We adapted this model with in vitro receptor binding data and clinical pharmacokinetic data of three intranasal nalmefene formulations along with an intranasal naloxone formulation to study the reversal of fentanyl and carfentanil-induced respiratory depression in chronic opioid users.
View Article and Find Full Text PDFSci Rep
January 2025
Faculty of Computer and Information, South Valley University, Qena, 83523, Egypt.
Ra, Th, and K levels in various foods frequently consumed by Egyptians were determined using a gamma-ray spectrometer based on the germanium detector (HPGe). Activity concentrations of Ra, Th, and K were in the range of < 0.10 to 0.
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