Cho Jin Dong, Son Jaeman, Sung Jiwon, Choi Chang Heon, Kim Jin Sung, Wu Hong-Gyun, Park Jong Min, Kim Jung-In
Department of Radiation Oncology, Seoul National University Hospital, Seoul, 03080, Republic of Korea.
Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, 03080, Republic of Korea.
Med Phys. 2020 Jul;47(7):3204-3213. doi: 10.1002/mp.14162. Epub 2020 Apr 30.
The aims of this study were to develop a flexible film dosimeter applicable to the irregular surface of a patient for in vivo dosimetry and to evaluate the device's dosimetric characteristics.
A flexible film dosimeter with active layers consisting of radiochromic-sensitive films and flexible silicone materials was constructed. The dose-response, sensitivity, scanning orientation dependence, energy dependence, and dose rate dependence of the flexible film dosimeter were tested. Irradiated dosimeters were scanned 24 h post-irradiation, and the region of interest was 5 mm × 5 mm. Biological stability tests ensured the safety of application of the flexible film dosimeter for patients. A preliminary clinical study with the flexible film dosimeter was implemented on four patients.
The red channel demonstrated the highest sensitivity among all channels, and the response sensitivity of the dosimeter decreased with the applied dose, which were the same as the characteristics of GAFCHROMIC EBT3 radiochromic films. The flexible film dosimeter showed no significant energy dependence for photon beams of 6 MV, 6 MV flattening filter-free (FFF), 10 MV, and 15 MV. The flexible film dosimeter showed no substantial dose rate dependence with 6 or 6 MV FFF. In terms of biological stability, the flexible film dosimeter demonstrated no cytotoxicity, no irritation, and no skin sensitization. In the preliminary clinical study, the dose differences between the measurements with the flexible film dosimeter and calculations with the treatment planning system ranged from -0.1% to 1.2% for all patients.
The dosimeter developed in this study is a flexible film capable of attachment to a curved skin surface. The biological test results indicate the stability of the flexible film dosimeter. The preliminary clinical study showed that the flexible film dosimeter can be successfully applied as an in vivo dosimeter.
本研究的目的是开发一种适用于患者不规则体表的柔性薄膜剂量仪用于体内剂量测定，并评估该设备的剂量学特性。
构建了一种具有由放射变色敏感薄膜和柔性硅酮材料组成的活性层的柔性薄膜剂量仪。测试了柔性薄膜剂量仪的剂量响应、灵敏度、扫描方向依赖性、能量依赖性和剂量率依赖性。辐照后的剂量仪在辐照后24小时进行扫描，感兴趣区域为5mm×5mm。生物稳定性测试确保了柔性薄膜剂量仪应用于患者的安全性。对4名患者进行了使用柔性薄膜剂量仪的初步临床研究。
红色通道在所有通道中显示出最高的灵敏度，剂量仪的响应灵敏度随施加剂量的增加而降低，这与GAFCHROMIC EBT3放射变色薄膜的特性相同。柔性薄膜剂量仪对6MV、6MV无均整器（FFF）、10MV和15MV的光子束没有明显的能量依赖性。柔性薄膜剂量仪对6MV或6MV FFF没有显著的剂量率依赖性。在生物稳定性方面，柔性薄膜剂量仪没有显示出细胞毒性、刺激性和皮肤致敏性。在初步临床研究中，所有患者使用柔性薄膜剂量仪测量值与治疗计划系统计算值之间的剂量差异范围为-0.1%至1.2%。
本研究中开发的剂量仪是一种能够附着在弯曲皮肤表面的柔性薄膜。生物测试结果表明了柔性薄膜剂量仪的稳定性。初步临床研究表明，柔性薄膜剂量仪可以成功地用作体内剂量仪。
