van Asselen Bram, Schwarz Marco, van Vliet-Vroegindeweij Corine, Lebesque Joos V, Mijnheer Ben J, Damen Eugene M F
Department of Radiation Oncology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
Radiother Oncol. 2006 May;79(2):162-9. doi: 10.1016/j.radonc.2006.04.010. Epub 2006 May 18.
To design a clinically reliable and efficient step-and-shoot IMRT delivery technique for the treatment of breast cancer using direct aperture optimization (DAO). Using DAO, segments are created and optimized within the same optimization process.
The DAO technique implemented in the Pinnacle treatment planning system, which is called direct machine parameter optimization (DMPO), was used to generate IMRT plans for twelve breast cancer patients. The prescribed dose was 50 Gy. Two DMPO plans were generated. The first approach uses DMPO only; the second technique combines DMPO with two predefined segments (DMPO(segm)), having shapes identical to the conventional tangential fields. The weight of these predefined segments is optimized simultaneously with DMPO. The DMPO plans were compared with normal two-step (TS) IMRT, creating segments after optimizing the intensity.
Dose homogeneity within the target volume was 4.8+/-0.6, 4.3+/-0.5 and 3.8+/-0.5 Gy for the TS, DMPO and DMPO(segm) plans, respectively. Comparing the IMRT plans with an idealized dose distribution obtained using only beamlet optimization, the degradation of the dose distribution was less for the DMPO plans compared with the two-step IMRT approach. Furthermore, this degradation was similar for all patients, while for the two-step IMRT approach it was patient specific.
An efficient step-and-shoot IMRT solution was developed for the treatment of breast cancer using DMPO combined with two predefined segments.
设计一种临床可靠且高效的步进式调强放疗（IMRT）投照技术，用于采用直接孔径优化（DAO）治疗乳腺癌。使用DAO时，在同一优化过程中创建并优化射野分段。
采用在Pinnacle治疗计划系统中实施的DAO技术，即直接机器参数优化（DMPO），为12例乳腺癌患者生成IMRT计划。处方剂量为50 Gy。生成了两个DMPO计划。第一种方法仅使用DMPO；第二种技术将DMPO与两个预定义射野分段（DMPO(segm)）相结合，其形状与传统切线野相同。这些预定义射野分段的权重与DMPO同时优化。将DMPO计划与常规两步（TS）IMRT进行比较，后者在优化强度后创建射野分段。
对于TS、DMPO和DMPO(segm)计划，靶区内剂量均匀性分别为4.8±0.6、4.3±0.5和3.8±0.5 Gy。将IMRT计划与仅使用子野优化获得的理想化剂量分布进行比较，与两步IMRT方法相比，DMPO计划的剂量分布退化较小。此外，所有患者的这种退化情况相似，而两步IMRT方法则因患者而异。
开发了一种高效的步进式调强放疗解决方案，用于采用DMPO结合两个预定义射野分段治疗乳腺癌。
