Medical Physics Department. Miguel Servet University Hospital Zaragoza, Spain.
Medical Physics Department. Miguel Servet University Hospital Zaragoza, Spain.
Phys Med. 2021 Jan;81:173-181. doi: 10.1016/j.ejmp.2020.12.011. Epub 2021 Jan 16.
The objectives of the study were to establish a procedure for in vivo film-based dosimetry for intraoperative radiotherapy (IORT), evaluate the typical doses delivered to organs at risk, and verify the dose prescription.
In vivo dose measurements were studied using XR-RV3 radiochromic films in 30 patients with breast cancer undergoing IORT using the Axxent® device (Xoft Inc.). The stability of the radiochromic films in the energy ranges used was verified by taking measurements at different depths. The stability of the scanner response was tested, and 5 different calibration curves were constructed for different beam qualities. Six pieces of film were placed in each of the 30 patients. All the pieces were correctly sterilized and checked to ensure that the process did not affect the outcome. All calibration and dose measurements were analyzed using the Radiochromic.com software application.
The doses were measured for 30 patients. The doses in contact with the applicator (prescription zone) were 19.8 ± 0.9 Gy. In the skin areas, the doses were as follows: 1-2 cm from the applicator, 1.86 ± 0.77 Gy; 2-5 cm, 0.73 ± 0.14 Gy; and greater than 5 cm, 0.28 ± 0.17 Gy. The dose delivered to the pectoral muscle (tungsten shielding disc) was 0.51 ± 0.27 Gy.
The study demonstrated the viability of XR-RV3 films for in vivo dose measurement in the dose and energy ranges applied in a complex procedure, such as breast IORT. The doses in organs at risk were far below the tolerances for cases such as those studied.
本研究的目的是建立一种用于术中放射治疗（IORT）的体内胶片剂量测定方法，评估对风险器官的典型剂量，并验证剂量处方。
在 30 名接受 Axxent®设备（Xoft Inc.）进行 IORT 的乳腺癌患者中，使用 XR-RV3 光致变色胶片进行了体内剂量测量。通过在不同深度处进行测量，验证了光致变色胶片在使用的能量范围内的稳定性。测试了扫描仪响应的稳定性，并为不同的射束质量构建了 5 个不同的校准曲线。在 30 名患者中的每一位患者中放置了 6 片胶片。所有的胶片都经过正确的消毒和检查，以确保处理过程不会影响结果。使用 Radiochromic.com 软件应用程序对所有的校准和剂量测量进行分析。
对 30 名患者进行了剂量测量。与施源器（处方区）接触的剂量为 19.8±0.9Gy。在皮肤区域，剂量如下：距施源器 1-2cm，1.86±0.77Gy；2-5cm，0.73±0.14Gy；大于 5cm，0.28±0.17Gy。胸肌（钨屏蔽盘）的剂量为 0.51±0.27Gy。
该研究证明了 XR-RV3 胶片在复杂程序（如乳房 IORT）中应用的剂量和能量范围内进行体内剂量测量的可行性。风险器官的剂量远低于所研究病例的耐受剂量。
