PDF(Pubmed)
Abstract：
UNASSIGNED: We aimed to establish if stereotactic body radiotherapy to the prostate can be delivered safely using reduced clinical target volume (CTV) to planning target volume (PTV) margins on the 1.5T MR-Linac (MRL) (Elekta, Stockholm, Sweden), in the absence of gating.
UNASSIGNED: Cine images taken in 3 orthogonal planes during the delivery of prostate SBRT with 36.25 Gray (Gy) in 5 fractions on the MRL were analysed. Using the data from 20 patients, the percentage of radiotherapy (RT) delivery time where the prostate position moved beyond 1, 2, 3, 4 and 5 mm in the left-right (LR), superior-inferior (SI), anterior-posterior (AP) and any direction was calculated.
UNASSIGNED: The prostate moved less than 3 mm in any direction for 90% of the monitoring period in 95% of patients. On a per-fraction basis, 93% of fractions displayed motion in all directions within 3 mm for 90% of the fraction delivery time. Recurring motion patterns were observed showing that the prostate moved with shallow drift (most common), transient excursions and persistent excursions during treatment.
UNASSIGNED: A 3 mm CTV-PTV margin is safe to use for the treatment of 5 fraction prostate SBRT on the MRL, without gating. In the context of gating this work suggests that treatment time will not be extensively lengthened when an appropriate gating window is applied.
UNASSIGNED: Cine images taken in 3 orthogonal planes during the delivery of prostate SBRT with 36.25 Gray (Gy) in 5 fractions on the MRL were analysed. Using the data from 20 patients, the percentage of radiotherapy (RT) delivery time where the prostate position moved beyond 1, 2, 3, 4 and 5 mm in the left-right (LR), superior-inferior (SI), anterior-posterior (AP) and any direction was calculated.
UNASSIGNED: The prostate moved less than 3 mm in any direction for 90% of the monitoring period in 95% of patients. On a per-fraction basis, 93% of fractions displayed motion in all directions within 3 mm for 90% of the fraction delivery time. Recurring motion patterns were observed showing that the prostate moved with shallow drift (most common), transient excursions and persistent excursions during treatment.
UNASSIGNED: A 3 mm CTV-PTV margin is safe to use for the treatment of 5 fraction prostate SBRT on the MRL, without gating. In the context of gating this work suggests that treatment time will not be extensively lengthened when an appropriate gating window is applied.
摘要：
■我们的目标是确定是否可以使用将临床目标体积（CTV）减小到1.5TMR-Linac（MRL）上的计划目标体积（PTV）边缘安全地对前列腺进行立体定向放射治疗（Elekta，斯德哥尔摩,瑞典),在没有门控的情况下。
■分析了在MRL上5个部分中在前列腺SBRT递送期间在3个正交平面中拍摄的电影图像，其中36.25灰色（Gy）。使用20名患者的数据，前列腺位置在左右（LR）移动超过1、2、3、4和5mm的放射治疗（RT）时间百分比，上级-下级(SI)，计算前后（AP）和任何方向。
■在95％的患者中，在90％的监测期内，前列腺在任何方向上移动不到3毫米。按分数计算，93%的部分在90%的部分递送时间内显示在3mm内的所有方向上的运动。观察到反复的运动模式，显示前列腺以浅漂移运动（最常见），治疗期间的短暂性旅行和持续性旅行。
■3mmCTV-PTV边缘可以安全地用于MRL上5个部位的前列腺SBRT的治疗，没有门控。在门控的背景下，这项工作表明，当应用适当的门控窗口时，治疗时间将不会大大延长。
■分析了在MRL上5个部分中在前列腺SBRT递送期间在3个正交平面中拍摄的电影图像，其中36.25灰色（Gy）。使用20名患者的数据，前列腺位置在左右（LR）移动超过1、2、3、4和5mm的放射治疗（RT）时间百分比，上级-下级(SI)，计算前后（AP）和任何方向。
■在95％的患者中，在90％的监测期内，前列腺在任何方向上移动不到3毫米。按分数计算，93%的部分在90%的部分递送时间内显示在3mm内的所有方向上的运动。观察到反复的运动模式，显示前列腺以浅漂移运动（最常见），治疗期间的短暂性旅行和持续性旅行。
■3mmCTV-PTV边缘可以安全地用于MRL上5个部位的前列腺SBRT的治疗，没有门控。在门控的背景下，这项工作表明，当应用适当的门控窗口时，治疗时间将不会大大延长。
