Po and Pb represent the most abundant part of atmospheric aerosol long-lived natural radioactivity. Moreover, Pb-Po monitoring in the atmosphere can be of interest for tracking extreme natural events that can enhance the level of alpha/beta radioactivity in air. In this paper, we question the possibility to use routine gross alpha/beta measurements in order to monitor Po, Pb and Po/Pb ratio in the atmosphere. Based on joint gross alpha/beta measurement and Pb-Po specific determination on 16 atmosphere samples, we show that (i) gross beta activity systematically overestimates Pb activity due to the presence of interfering beta emitters and (ii) gross alpha activity mostly reflects Po activity even if an underestimation is always observed due to alpha particle attenuation in the sample. In order to determine Po/Pb ratio, we discuss the advantages of using gross alpha activity time variation compared to specific Po measurements. Finally, the gross alpha/beta ratio appear to be a good proxy of the Po/Pb ratio when large-scale variations are to be monitored. We report a first reference level for the activity level of airborne Po in France of 13 ± 6 μBq/m.
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http://dx.doi.org/10.1016/j.jenvrad.2020.106437 | DOI Listing |
Clin Transl Radiat Oncol
March 2025
Radiation Oncology Department, Cancer Institute Hospital, Japanese Foundation for Cancer Research, 3-8-31 Ariake, Koto-ku, Tokyo 135-8550, Japan.
Background And Purpose: In lung stereotactic body radiation therapy (SBRT) using a breath-holding technique, displacement of tumor during breath-holding is rarely considered. This study used four-dimensional (4D) dose calculation with cine computed tomography (CT) to evaluate the impact of unexpected tumor position displacement during breath-holding on the target dose of lung volumetric modulated arc therapy (VMAT)-SBRT.
Materials And Methods: This study included 20 cases for which tumor position displacement during end-exhalation breath-holding (range: 0.
Elife
January 2025
Calcium Signaling Group, Research Department, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar.
The steroid hormone progesterone (P4) regulates multiple aspects of reproductive and metabolic physiology. Classical P4 signaling operates through nuclear receptors that regulate transcription. In addition, P4 signals through membrane P4 receptors (mPRs) in a rapid nongenomic modality.
View Article and Find Full Text PDFAppl Radiat Isot
February 2025
University of Southampton, National Oceanography Centre, European Way, Southampton, SO14 3ZH, UK, UK.
Gross alpha & beta measurement is a widely used technique for rapid screening of radionuclide content. The study evaluated the influence of geometry, alpha & beta energy and presence of natural decay chain nuclides on the observed gross alpha & beta response. Measured calibration data were validated using Monte Carlo-based modelling.
View Article and Find Full Text PDFRadiother Oncol
January 2025
Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa 33612, FL, USA. Electronic address:
Soft tissue sarcomas (STS) are radioresistant with a low α/β, which may have a biologic benefit with hypofractionation. For unresectable STS, the dose escalation required to achieve durable control is often limited by long-term toxicity risk. We sought to compare an isotoxic approach utilizing hypofractionated accelerated radiation dose-painting (HARD) versus standard fractionated radiation therapy (SFT) in patients with unresected STS.
View Article and Find Full Text PDFEnviron Geochem Health
November 2024
Department of Physics, Sidho-Kanho-Birsha University, Purulia, 723104, India.
In the present study, liquid scintillation counting triple to double coincidence ratio technique is used to ascertain the gross α and β activity in groundwater samples collected from the Beldih mine region in the vicinity of the South Purulia Shear Zone (SPSZ) of Chota Nagpur Plateau in eastern India. A total of sixty samples were collected from deep tube wells located in the study area to assess the potential health threats caused by α and β emitting radionuclides present in these water samples. Average gross α activity in the region of study is 0.
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