Naomasa Narihiro    Department   Kawasaki University of Medical Welfare  ,    Position   Associate Professor
Article types	原著
Language	English
Peer review	Peer reviewed
Title	Oblique Surface Dose Calculation in High Energy X-ray Therapy
Journal	Formal name：Acta Medica Okayama
Domestic / Foregin	Foregin
Volume, Issue, Page	74(5),pp.415-422
Author and coauthor	Narihiro Naomasa, Oita Masataka, Yoshihiro Takeda
Authorship	Lead author
Publication date	2020/10/20
Summary	During radiation therapy, incident radiation oblique to the skin surface is high and may cause severe skin damage. Understanding the dose of radiation absorbed by the skin is important for predicting skin damage due to radiation. In this study, we used a high-energy (4 MV) X-ray system and an optically stimulated luminescence dosimeter (OSLD) that was developed for personal exposure dosimetry. We determined the dose variation and angular dependence, which are the characteristics of a small OSLD required to derive the calculation formula for the oblique surface dose. The dose variation was determined using the coefficient of variation. The maximum coefficient of variation for 66 small-field OSLDs was 1.71%. The angular dependence, obtained from the dose ratio of the dosimeter in the vertical direction, had a maximum value of 1.37. We derived a new equation in which the oblique surface dose can be calculated within the error range of −7.7–5.1%.