van Lin E N, Nijenhuis E, Huizenga H, van der Vight L, Visser A
Joint Center for Radiation Oncology Arnhem-Nijmegen, University Medical Center Nijmegen, The Netherlands.
Int J Radiat Oncol Biol Phys. 2001 Jun 1;50(2):569-77. doi: 10.1016/s0360-3016(01)01520-6.
To investigate set-up improvement caused by applying a couch height-based patient set-up method in combination with a technologist-driven off-line correction protocol in nonimmobilized radiotherapy of prostate patients.
A three-dimensional shrinking action level correction protocol is applied in two consecutive patient cohorts with different set-up methods: the traditional "laser set-up" group (n = 43) and the "couch height set-up" group (n = 112). For all directions, left-right, ventro-dorsal, and cranio-caudal, random and systematic set-up deviations were measured.
The couch height set-up method improves the patient positioning compared to the laser set-up method. Without application of the correction protocol, both systematic and random errors reduced to 2.2-2.4 mm (1 SD) and 1.7-2.2 mm (1 SD), respectively. By using the correction protocol, systematic errors reduced further to 1.3-1.6 mm (1 SD). One-dimensional deviations were within 5 mm for >90% of the measured fractions. The required number of corrections per patient in the off-line correction protocol was reduced significantly during the course of treatment from 1.1 to 0.6 by the couch height set-up method. The treatment time was not prolonged by application of the correction protocol.
The couch height set-up method improves the set-up significantly, especially in the ventro-dorsal direction. Combination of this set-up method with an off-line correction strategy, executed by technologists, reduces the number of set-up corrections required.
研究在前列腺患者非固定放射治疗中，应用基于治疗床高度的患者摆位方法并结合技术人员驱动的离线校正方案所带来的摆位改善情况。
在两个采用不同摆位方法的连续患者队列中应用三维收缩行动水平校正方案：传统的“激光摆位”组（n = 43）和“治疗床高度摆位”组（n = 112）。对于左右、腹背和头脚所有方向，测量随机和系统摆位偏差。
与激光摆位方法相比，治疗床高度摆位方法改善了患者定位。在未应用校正方案时，系统误差和随机误差分别降至2.2 - 2.4毫米（1标准差）和1.7 - 2.2毫米（1标准差）。通过使用校正方案，系统误差进一步降至1.3 - 1.6毫米（1标准差）。超过90%的测量分次中一维偏差在5毫米以内。在治疗过程中，治疗床高度摆位方法使离线校正方案中每位患者所需的校正次数从1.1显著减少至0.6。应用校正方案未延长治疗时间。
治疗床高度摆位方法显著改善了摆位，尤其是在腹背方向。这种摆位方法与技术人员执行的离线校正策略相结合，减少了所需的摆位校正次数。
