Open AccessEffect of protective glasses on radiation dose to eye lenses during whole breast irradiation
Author(s) -
Nakamura Tokiko,
Suzuki Shoichi,
Kato Kyoichi,
Pongnapang Napapong,
Hayashi Naoki,
Kurokawa Chie,
Kobayashi Ikuo,
Negishi Toru,
Matsunami Tamaki
Publication year - 2020
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.13073
Subject(s) - irradiation , dosimeter , nuclear medicine , imaging phantom , radiation therapy , medicine , materials science , field size , dosimetry , optics , physics , surgery , nuclear physics
Objectives The efficacy of radiotherapy for breast cancer has greatly improved owing to better irradiation methods. Radiotherapy aims to deliver therapeutic doses to predetermined target volumes while sparing surrounding healthy tissues. However, there are few reports on radiation exposure to eye lenses, and the recommended exposure limits to ocular lens have been substantially reduced in recent years. This study aimed to investigate the amount of radiation exposure to eye lenses using optically stimulated luminescence dosimeters (OSLDs) and determine whether wearing special protective devices to protect the eyes, as an organ at risk, during whole breast irradiation, is necessary. Methods This experiment used OSLDs on water‐equivalent phantom to measure the change in scattered radiation dose due to the difference of irradiation field while using 4‐ and 6‐MV photons of TrueBeam linear accelerator. Using a total treatment dose of 50 Gy, a target was positioned to approximate the breast, and a plan was formulated to deliver 2 Gy per treatment by tangential irradiation. The mean (SD) irradiation dose at the lens position outside the irradiation field was reported. Results The scattered radiation dose outside the irradiation field was more affected by the irradiation field size than by the radiation energy. The out‐of‐field irradiation dose with a larger field of view was higher than that with a smaller field of view. The use of 0.07‐ and 0.83‐mm‐thick lead shield protective glasses reduced the radiation dose by 56.1% ( P < .001) and 55.6% ( P < .001), respectively. Conclusions In this experimental model, the amount of radiation the eye was exposed to during whole breast irradiation was determined by the distance of the eye from the radiation field edge and by wearing protective glasses. In clinical practice, the protection offered by eyeglasses may reduce the risk of long‐term side effects and allow the use of higher intensive radiotherapy.