Acta Medica Okayama volume74 issue5
2020-10 発行

Oblique Surface Dose Calculation in High-Energy X-ray Therapy

Narihiro, Naomasa Graduate School of Health Sciences, Department of Radiological Technology, Okayama University
Oita, Masataka Department of Graduate School of Interdisciplinary Sciences and Engineering in Health Systems, Okayama University Kaken ID researchmap
Takeda, Yoshihiro Graduate School of Health Sciences, Department of Radiological Technology, Okayama University Kaken ID publons researchmap
Publication Date
2020-10
Abstract
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%.
Document Type
Original Article
Keywords
optically stimulated luminescent dosimeter
radiotherapy
oblique surface dose
high-energy X-ray therapy
angular dependence
Link to PubMed
74_5_415.pdf 3.42 MB