Japanese pediatric and adult atomic bomb survivor dosimetry: potential improvements using the J45 phantom series and modern Monte Carlo transport

The radiation exposure estimates for the atomic bomb survivors at Hiroshima and Nagasaki have evolved over the past several decades, reflecting a constant strive by the Radiation Effects Research Foundation (RERF) to provide thorough dosimetry to their cohort. Recently, a working group has introduced a new series of anatomical models, called the J45 phantom series, which improves upon those currently used at RERF through greater age resolution, sex distinction, anatomical realism, and organ dose availability. To evaluate the potential dosimetry improvements that would arise from their use in an RERF Dosimetry System, organ doses in the J45 series are evaluated here using environmental fluence data for 20 generalized survivor scenarios pulled directly from the current dosimetry system. The energy- and angle-dependent gamma and neutron fluences were converted to a source term for use in MCNP6, a modern Monte Carlo radiation transport code. Overall, the updated phantom series would be expected to provide dose improvements to several important organs, including the active marrow, colon, and stomach wall (up to 20, 20, and 15% impact on total dose, respectively). The impacts were especially significant for neutron dose estimates (up to a two-fold difference) and within organs which were unavailable in the previous phantom series. These impacts were consistent across the 20 scenarios and are potentially even greater when biological effectiveness of the neutron dose component is considered. The entirety of the dosimetry results for all organs are available as supplementary data, providing confident justification for potential future DS workflows utilizing the J45 phantom series.

The international calibration procedure for B3 film dosimetry system to ensure the quality irradiated products by 10 MeV electron beam accelerators at VINAGAMMA

We performed an in-plant calibration of dosimetry system by electron beam (EB)irradiating the B3 film dosimeters at VINAGAMMA, and inter-compared with the alanine dosimetry, which were supplied and analyzed by Risø High Dose Reference Laboratory (HDRL) as the reference standard. The results revealed that the relative deviation between the values of absorbed doses obtained with our dosimeter and the transfer standards dosimeter measured by HDRL was within the acceptable limitation (about ± 3.0 % in the target range of 2.0-10.0 kGy). And post-irradiation stability of B3 film dosimeters was still maintained after 180 days storage. It is suggested that the B3 filmdosimetry could be used in routine radiation processing at VINAGAMMA with the investigated dose range for quality assurance of the irradiated products, specially are foods and foodstuffs processed under the 10 MeV EB accelerator at VINAGAMMA.

A protocol for accurate radiochromic film dosimetry using Radiochromic.com

Background Radiochromic films have many applications in radiology and radiation therapy. Generally, the dosimetry system for radiochromic film dosimetry is composed of radiochromic films, flatbed scanner, and film analysis software. The purpose of this work is to present the effectiveness of a protocol for accurate radiochromic film dosimetry using Radiochromic.com as software for film analysis. Materials and methods Procedures for image acquisition, lot calibration, and dose calculation are explained and analyzed. Radiochromic.com enables state-of-the-art models and corrections for radiochromic film dosimetry, such as the Multigaussian model for multichannel film dosimetry, and lateral, inter-scan, and re-calibration corrections of the response. Results The protocol presented here provides accurate dose results by mitigating the sources of uncertainty that affect radiochromic film dosimetry. Conclusions Appropriate procedures for film and scanner handling in combination with Radiochromic.com as software for film analysis make easy and accurate radiochromic film dosimetry feasible.

Experimental study on SAR reduction from cell phones

<p class="Abstract">The actual problem of the human exposure to different types of electromagnetic field sources is a challenging one and should be considered an up to date issue due to one major actual trend: the increasingly intensive penetration of various wireless communication technologies in virtually all places and times that make up our daily lives. The here presented paper presents an experimental study focused on measurements for three types of mobile phones, belonging to different generations, operating at the two characteristic frequencies of the GSM bandwidth. We have been used a SATIMO-COMOSAR evaluation dosimetry system, provided by the LICETER laboratory of ANCOM Romania. The determined values of the absorbed incident energy by the tissue of a mannequin (phantom) model for the human head, which is part of the dosimetry system, have been also compared with those obtained in the case when the mobile phones are protected by multilayer cases, aiming to study their possible limiting effect. The influence that ”touch” or ”tilt” positions might have on absorbed (by the human head model) incident energy values has also been investigated. The comparative processing of the obtained results allowed the formulation of recommendations on reducing the exposure to electromagnetic radiation associated with the use of the mobile phone. This paper is an extended and improved version of the original contribution to the IMEKO TC 4 2020 virtual conference.</p>