Influence of intrafraction motion on margins for prostate radiotherapy
Influence of intrafraction motion on margins for prostate radiotherapy
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DOI：
10.1016/j.ijrobp.2005.12.033
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发表时间：
2006-06-01
影响因子：
7
通讯作者：
Levine, L
中科院分区：
文献类型：
--
作者：
Litzenberg, DW;Balter, JM;Levine, L
目的：探讨在前列腺放射治疗中行抽运介入对切缘的影响。方法与材料：对11例平卧前列腺患者进行了3个应答器植入术的研究。监测相对应答器位置8分钟，并结合先前测量的前列腺位置相对于皮肤标记的数据。确定了(1)基于皮肤定位和(2)预处理应答器定位两种情况的边缘。假设(1)连续跟踪，(2)位置校正阈值为3 mm，模拟治疗内干预。结果：对于没有或包含抽束内运动的基于皮肤的设置，前列腺治疗将需要大约左右、前后和颅尾方向的平均切缘分别为8.0、7.3和10.0 mm和8.2、10.2和12.5 mm。在治疗开始时，前列腺标记物的定位将这些值分别降低到1.8、5.8和7.1 mm。梁间调节进一步将间隙减小到平均1.4、2.3和1.8毫米。梁内调整产生的边际分别为1.3、1.5和1.5毫米。结论：通过在每次光束前重新定位患者，无论是放射还是电磁，都可以显著减少边缘。然而，11例患者中有2例将受益于持续的目标跟踪和基于阈值的干预。(c) 2006爱思唯尔公司
Purpose: To assess the impact of intrafraction intervention on margins for prostate radiotherapy.Methods and Materials: Eleven supine prostate patients with three implanted transponders were studied. The relative transponder positions were monitored for 8 min and combined with previously measured data on prostate position relative to skin marks. Margins were determined for situations of (1) skin-based positioning, and (2) pretreatment transponder positioning. Intratreatment intervention was simulated assuming conditions of (1) continuous tracking, and (2) a 3-mm threshold for position correction.Results: For skin-based setup without and with inclusion of intrafraction motion, prostate treatments would have required average margins of 8.0, 7.3, and 10.0 mm and 8.2, 10.2, and 12.5 mm, about the left-right, anterior-posterior, and cranial-caudal directions, respectively. Positioning by prostate markers at the start of the treatment fraction reduced these values to 1.8, 5.8, and 7.1 mm, respectively. Interbeam adjustment further reduced margins to an average of 1.4, 2.3, and 1.8 mm. Intrabeam adjustment yielded margins of 1.3, 1.5, and 1.5 mm, respectively.Conclusion: Significant reductions in margins might be achieved by repositioning the patient before each beam, either radiographically or electromagnetically. However, 2 of the 11 patients would have benefited from continuous target tracking and threshold-based intervention. (c) 2006 Elsevier Inc.