Analysis of the DS86 atomic bomb radiation dosimetry methods using data on severe epilation

Area of Science:

• Radiation Biology
• Epidemiology
• Dosimetry

Background:

• Severe epilation in Hiroshima and Nagasaki survivors is a key acute radiation effect.
• Previous analyses by Jablon et al. and Gilbert & Ohara examined epilation data.
• Reanalysis uses updated DS86 dosimetry alongside the older T65D system.

Purpose of the Study:

• To reanalyze severe epilation data from Hiroshima and Nagasaki using DS86 and T65D dosimetries.
• To investigate epilation response uniformity across demographic and shielding factors.
• To assess the relative biological effectiveness (RBE) of neutrons and dose-response nonlinearity.

Main Methods:

• Comparative reanalysis of severe epilation data using DS86 and T65D dosimetries.
• Examination of epilation response across shielding categories, sex, and age.
• Analysis of interactions between city, sex, age, and shielding; assessment of RBE and dose-response curves.

Main Results:

• DS86 dosimetry increases the apparent RBE of neutrons versus gamma dose (approx. 5-10) compared to T65D.
• The slope of the dose-response curve (0.75-2.5 Gy) is ~165% steeper with DS86.
• Nonuniformities in epilation response observed with T65D persist with DS86; DS86 is not a better predictor.

Conclusions:

• DS86 dosimetry reveals higher neutron RBE and more pronounced dose-response nonlinearity, including a downturn at high doses.
• The apparent downturn in DS86 is partly due to T65D dose truncation at 600 rad.
• DS86 does not offer improved prediction of epilation response over T65D, despite dosimetry differences.