PELVIC RADIOTHERAPY FOR CANCER OF THE CERVIX: IS WHAT YOU PLAN ACTUALLY WHAT YOU DELIVER?
PELVIC RADIOTHERAPY FOR CANCER OF THE CERVIX: IS WHAT YOU PLAN ACTUALLY WHAT YOU DELIVER?
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DOI：
10.1016/j.ijrobp.2008.12.043
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发表时间：
2009-05-01
影响因子：
7
通讯作者：
Milosevic, Michael
中科院分区：
文献类型：
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作者：
Lim, Karen;Kelly, Valerie;Milosevic, Michael
目的：全盆腔调强放疗（IMRT）越来越多地应用于宫颈癌和其他妇科肿瘤的治疗。然而，在治疗过程中，肿瘤和正常器官的运动可能会大大减少这种方法的好处。本研究采用可变形软组织模型与模拟剂量累积相结合的策略，探讨了内部解剖变化对输送到肿瘤和危险器官的剂量的影响。方法和材料：20例宫颈癌患者在治疗期间接受基线和每周盆腔磁共振成像。模拟了三种治疗方案：四场箱、大切缘全盆腔IMRT（计划靶体积为20mm，但小于10mm）和小切缘IMRT（计划靶体积为5mm）。结果：个体计划给药剂量与模拟给药剂量不一致；然而，当作为一个群体时，这对于四场框和大边际IMRT计划没有统计学意义。小范围IMRT计划在大多数患者中获得了足够的目标覆盖率；然而，1例患者表现出过度的、不可预测的内部靶标运动，出现了明显的靶标剂量不足。尽管患者之间存在很大的差异，但小边际计划显著减少了对危险器官的递送剂量。结论：模拟剂量累积可以更准确地描述宫颈癌分次全盆腔放射治疗中靶和危险器官的覆盖范围。原发肿瘤覆盖的充分性使用5毫米计划靶体积边界取决于每日图像引导设置的使用。(C) 2009爱思唯尔公司
Purpose: Whole pelvic intensity-modulated radiotherapy (IMRT) is increasingly being used to treat cervix cancer and other gynecologic tumors. However, tumor and normal organ movement during treatment can substantially detract from the benefits of this approach. This study explored the effect of internal anatomic changes on the dose delivered to the tumor and organs at risk using a strategy integrating deformable soft-tissue modeling with simulated dose accumulation.Methods and Materials: Twenty patients with cervix cancer underwent baseline and weekly pelvic magnetic resonance imaging during treatment. Interfraction organ motion and delivered (accumulated) dose was modeled for three treatment scenarios: four-field box, large-margin whole pelvic IMRT (20-mm planning target volume, but 10 mm inferiorly) and small-margin IMRT (5-mm planning target volume).Results: Individually, the planned dose was not the same as the simulated delivered dose; however, when taken as a group, this was not statistically significant for the four-field box and large-margin IMRT plans. The small-margin IMRT plans yielded adequate target coverage in most patients; however, significant target underdosing occurred in I patient who displayed excessive, unpredictable internal target movement. The delivered doses to the organs at risk were significantly reduced with the small-margin plan, although substantial variability was present among the patients.Conclusion: Simulated dose accumulation might provide a more accurate depiction of the target and organ at risk coverage during fractionated whole pelvic IMRT for cervical cancer. The adequacy of primary tumor coverage using 5-mm planning target volume margins is contingent on the use of daily image-guided setup. (C) 2009 Elsevier Inc.