Suzuki Tenyoh, Ohira Shingo, Ogita Mami, Ohta Takeshi, Nozawa Yuki, Minamitani Masanari, Hayashi Takuya, Saegusa Shigeki, Imae Toshikazu, Ueyama Tsuyoshi, Katano Atsuto, Yamashita Hideomi, Chang Weishan, Nakagawa Keiichi
Department of Radiological Sciences, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Arakawa-ku, Tokyo, Japan.
Department of Comprehensive Radiation Oncology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
J Appl Clin Med Phys. 2025 Jun;26(6):e70070. doi: 10.1002/acm2.70070. Epub 2025 Mar 13.
This study aims to quantify and compare the dosimetric effects of varying thicknesses of StrataXRT, a silicone-based gel, and other topical agents on the skin surface during volumetric modulated arc therapy (VMAT) for breast cancer.
A VMAT plan was created for breast cancer treatment using a female RANDO phantom with a prescription dose of 50 Gy in 25 fractions. The planning target volume (PTV) encompassed the left breast and the regional lymph nodes. Irradiation was performed using a 6 MV photon beam. Three topical agents (StrataXRT, Hirudoid Soft Ointment, and RINDERON-Vs Ointment) having eight thicknesses (0.0-1.5 mm) were evaluated. Dosimetry was conducted using Gafchromic EBT4 films at three anatomical locations-subclavicular, medial, and lateral aspects of the left breast.
Mean dose enhancement ratios (DERs) of 102%-116% were observed in VMAT for topical agent thicknesses of 0.1-0.5 mm, increasing to 116%-126% at 1.0 and 1.5 mm. Among the evaluated agents, StrataXRT consistently exhibited the lowest DER, with a statistically significant difference (p < 0.05).
This study demonstrated that StrataXRT exhibited the lowest DER among the evaluated topical agents in VMAT for breast cancer. Thicknesses exceeding 0.5 mm potentially exceeded the threshold dose for acute skin reactions.
本研究旨在量化并比较不同厚度的StrataXRT（一种硅基凝胶）及其他局部用药在乳腺癌容积调强弧形放疗（VMAT）过程中对皮肤表面的剂量学影响。
使用女性RANDO体模为乳腺癌治疗制定VMAT计划，处方剂量为25次分割、每次50 Gy。计划靶区（PTV）包括左侧乳腺和区域淋巴结。采用6 MV光子束进行照射。评估了三种局部用药（StrataXRT、喜疗妥软膏和维蕾德-Vs软膏），每种药物有八种厚度（0.0 - 1.5 mm）。在左侧乳腺的三个解剖位置（锁骨下、内侧和外侧）使用Gafchromic EBT4胶片进行剂量测定。
在VMAT中，对于厚度为0.1 - 0.5 mm的局部用药，平均剂量增强率（DER）为102% - 116%，在厚度为1.0和1.5 mm时增加到116% - 126%。在评估的药物中，StrataXRT始终表现出最低的DER，具有统计学显著差异（p < 0.05）。
本研究表明，在乳腺癌VMAT中，StrataXRT在所评估的局部用药中表现出最低的DER。厚度超过0.5 mm可能超过急性皮肤反应的阈值剂量。
