Department of Radiotherapy and Oncology, Goethe University Frankfurt, Frankfurt, Germany.
Department of Radiation Oncology, University of Wuerzburg, Wuerzburg, Germany.
J Appl Clin Med Phys. 2023 Oct;24(10):e14042. doi: 10.1002/acm2.14042. Epub 2023 Sep 7.
To evaluate the possible advantages of a simple spinal cord (SC) dose-limiting three-dimensional conformal radiotherapy (3D-CRT) technique in comparison to conventional two-dimensional (2D) techniques and other 3D-CRT techniques for spinal bone irradiation.
For 41 spinal target volumes, seven different techniques were evaluated, using a standard schedule of 30 Gy in 10 fractions. The SC dose-limiting 3D-CRT technique 1F2S-18MV using a single posterior field (F) supplemented by two anterior segment fields (S) and 18-MV photon beams was compared to two conventional 2D techniques (a single posterior field, PA, and two opposed anterior-posterior fields, APPA), three other 3D-CRT techniques (a single posterior field supplemented by four segment fields, 1F4S; two wedged fields, WD, and the SC dose-limiting variant using 6 MV, 1F2S-6MV) along with the original clinically applied plans.
1F2S-18MV demonstrated notably better results for all target volume parameters compared to the conventional 2D techniques (p < 0.001). Limitation of the SC dose was significantly superior with 1F2S-18MV in comparison to PA and APPA (SC Dmean: 28.9 ± 0.4 vs. 30.1 ± 0.6 Gy and 30.1 ± 0.4 Gy; SC Dmax: 30.9 ± 0.7 vs. 32.5 ± 1.0 Gy and 31.8 ± 0.7 Gy; SC D1cm : 30.1 ± 0.6 vs. 31.7 ± 0.9 Gy and 31.1 ± 0.6 Gy; p < 0.001). Likewise, lower mean SC doses with 1F2S-18MV were observed in comparison to the more treatment time-consuming 3D-CRT techniques (1F4S, WD) and the original plans without relevant compromises on the dose homogeneity in the target volume and the dose exposure to the other OARs.
In treatment planning of spinal metastases, simple variants of 3D-CRT-techniques like 1F2S-18MV can offer a significant dose limitation to the SC while providing a sufficient dose coverage of the target volume. Especially in patients with favorable life expectancy and potential need for re-irradiation, such SC dose-limiting 3D-CRT techniques may be a reasonable approach.
为了评估一种简单的脊髓（SC）剂量限制三维适形放疗（3D-CRT）技术相对于传统二维（2D）技术和其他用于脊柱骨照射的 3D-CRT 技术的可能优势。
对于 41 个脊髓靶区，使用标准的 30Gy/10 次分割方案，评估了七种不同的技术。使用单后野（F）加两个前野（S）和 18-MV 光子束的 SC 剂量限制 3D-CRT 技术 1F2S-18MV 与两种传统的 2D 技术（单后野 PA 和两个对穿前后野 APPA）、三种其他 3D-CRT 技术（单后野加四个节段野 1F4S、两个楔形野 WD 和使用 6MV 的 SC 剂量限制变体 1F2S-6MV）以及最初临床应用的计划进行了比较。
与传统的 2D 技术相比，1F2S-18MV 对所有靶区参数均显示出明显更好的结果（p<0.001）。与 PA 和 APPA 相比，1F2S-18MV 对 SC 剂量的限制明显更好（SC Dmean：28.9±0.4Gy 比 30.1±0.6Gy 和 30.1±0.4Gy；SC Dmax：30.9±0.7Gy 比 32.5±1.0Gy 和 31.8±0.7Gy；SC D1cm：30.1±0.6Gy 比 31.7±0.9Gy 和 31.1±0.6Gy；p<0.001）。同样，与更耗时的 3D-CRT 技术（1F4S、WD）以及无相关靶区剂量均匀性和其他 OAR 剂量暴露妥协的原始计划相比，1F2S-18MV 也观察到较低的平均 SC 剂量。
在脊柱转移瘤的治疗计划中，简单的 3D-CRT 技术变体，如 1F2S-18MV，可以对 SC 进行显著的剂量限制，同时为靶区提供足够的剂量覆盖。对于预期寿命良好且有再次放疗需求的患者，这种 SC 剂量限制的 3D-CRT 技术可能是一种合理的方法。
