Comparison of the UNSCEAR isodose maps for annual external exposure in Fukushima with those obtained based on airborne monitoring surveys

Abstract

In 2016, UNSCEAR published an attachment to its Fukushima 2015 White Paper, entitled 'Development of isodose maps representing annual external exposure in Japan as a function of time', in which the committee presented an annual additional 1 mSv effective dose ab extra isodose lines for 1, 3, 5, 10, 30, 50 years after the accident, based on the soil deposition data of radionuclides within 100 km of the Fukushima Dai-ichi Nuclear Power Plant. Meanwhile, the median of the ratio, c, between the external effective dose rates and the ambient dose equivalent rates 1 m above the ground obtained by airborne monitoring has been established to be [Formula: see text]. Here, we compare the UNSCEAR predictions with estimates based on the airborne monitoring. Although both the methods and the data used in the two approaches are different, the resultant contours show relatively good agreement. However, to improve the accuracy of long-term annual effective isodose lines, feedback from continuous measurements such as airborne monitoring is important.

Creation of Safe Dose Zones Using Isodose Maps in Video Fluoroscopic Swallowing Studies for Pediatric Patients

“…The construction of isodose maps provided a visual representation of the spatial distribution of radiation in the procedure room. These maps allow for the identification of critical exposure areas, where doses are higher, and lower-risk zones, where doses are lower, in line with the objectives of Hayano et al 2018(10) and Kissick et al 2024(9), who created isodose maps to determine areas of high and low doses for various purposes. When analyzing these maps, it can be observed that certain areas of the room, such as those near the patient or the X-ray tube, tend to have higher doses, while other areas, such as locations further from the point of radiation emission, show lower doses, similarly to Poveda et al 2020(11).…”

“…For the study of dose distribution, isodose maps have been widely used in radiation therapy treatments to assess the doses reaching the target organ and neighboring organs (8). Tests have also been conducted to evaluate the dose environment in Computed Tomography, in order to observe which areas receive higher and lower doses (9)In 2021 an article investigated through isodose maps the doses received in a city affected by radiation in order to observe through colored zones which parts are more exposed to radiation (10). In the article titled "Radiation Protection Elements in Interventional Rooms" (11) the distribution of doses was analyzed using isodose maps around the patient and exposed personnel, determining areas of higher dose around the patient.…”

Corrigendum: Comparison of the UNSCEAR isodose maps for annual external exposure in Fukushima with those obtained based on airborne monitoring surveys (2018 J. Radiol. Prot. 38 310)

“…In [1], the ratio c between the external effective dose rates and the ambient dose equivalent rates 1 m above the ground obtained by airborne monitoring was chosen to be c ∼ 0.15, referring to reference [5] of [1]. Since reference [5] of [1] has recently been retracted due to ethical concerns [2], modifications listed below need to be applied to [1].…”

“…In [1], the ratio c between the external effective dose rates and the ambient dose equivalent rates 1 m above the ground obtained by airborne monitoring was chosen to be c ∼ 0.15, referring to reference [5] of [1]. Since reference [5] of [1] has recently been retracted due to ethical concerns [2], modifications listed below need to be applied to [1]. This, however, does not affect the conclusions of [1], since our choice of c ∼ 0.15 is supported by another independent study conducted in Fukushima, namely, reference [10] of [1] (c ∼ 0.13 for time spent at home and c ∼ 0.18 for time spent outdoors).…”

“…Since reference [5] of [1] has recently been retracted due to ethical concerns [2], modifications listed below need to be applied to [1]. This, however, does not affect the conclusions of [1], since our choice of c ∼ 0.15 is supported by another independent study conducted in Fukushima, namely, reference [10] of [1] (c ∼ 0.13 for time spent at home and c ∼ 0.18 for time spent outdoors).…”