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Updated: Jun 19, 2026

Irradiator Commissioning and Dosimetry for Assessment of LQ α and β Parameters, Radiation Dosing Schema, and in vivo Dose Deposition
Published on: March 11, 2021
An alpha-particle irradiator for radiobiological research and its implementation for bystander effect studies
Giuseppe Esposito1, Francesca Antonelli, Mauro Belli
1Health and Technology Department, Istituto Superiore di Sanità, and INFN Sezione di Roma1 Gruppo Collegato Sanità, Roma, Italy. giuseppe.esposito@iss.infn.it
Abstract:
An experimental system based on an improved version of an existing alpha-particle irradiator has been developed for radiobiological studies, in particular those investigating bystander effects. It consists of a 20-mm-diameter stainless steel chamber that can be equipped alternatively with 244Cm or 241Am sources of different activities. Mylar-based petri dishes 56 mm in diameter were specially designed to house adaptors for permeable membrane inserts that reproduce the geometry of commercial cell culture insert companion plates. Characterization of the radiation field at the cell level was performed by experimental measurements and calculations. The average incident LET was about 122 keV/microm for 244Cm and about 125 keV/microm for 241Am. Dose rates at the chosen source-sample distance were 2.8 and 88.6 mGy/min, respectively. These low dose rates are suitable for our planned experiments on low-dose effects. For both sources, the uniformity of the alpha-particle dose was better than +/-7%, and the photon dose calculated at the cell entrance was negligible compared to the alpha-particle dose. The irradiator is small enough to be inserted into a cell incubator for irradiation under physiological conditions or into a refrigerator to prevent metabolic processes during irradiation. Benchmark experiments using the 241Am source to examine DNA double-strand breaks in directly hit and bystander primary human fibroblasts have shown that the irradiator can be used successfully for bystander effect studies.
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