Department of Oncology, Aarhus University Hospital, Denmark.
Department of Oncology, Aarhus University Hospital, Denmark.
Radiother Oncol. 2017 Apr;123(1):158-163. doi: 10.1016/j.radonc.2017.01.015. Epub 2017 Feb 9.
To implement coverage probability (CovP) for dose planning of simultaneous integrated boost (SIB) of pathologic lymph nodes in locally advanced cervical cancer (LACC).
CovP constraints for SIB of the pathological nodal target (PTV-N) with a central dose peak and a relaxed coverage at the perimeter were generated for use with the treatment planning system Eclipse: PTV-N D98 >90%, CTV-N D98 >100% and CTV-N D50 >101.5% of prescribed dose. Dose of EBRT was 45Gy/25 fx with a SIB of 55-57.5Gy depending on expected dose from brachytherapy (BT). Twenty-five previously treated patients with 47 boosted nodes were analysed. Nodes were contoured on cone beam CT (CBCT) and the accumulated dose in GTV-N and volume of body, pelvic bones and bowel receiving >50Gy (V50) were determined.
Nearly all nodes (89%) were visible on CBCT and showed considerable concentric regression during EBRT. Total EBRT and BT D98 was >57 Gy in 98% of the visible nodes. Compared to treatment plans aiming for full PTV-N coverage, CovP significantly reduced V50 of body, bones and bowel (p<0.001) CONCLUSION: CovP is clinically feasible for SIB of pathological nodes and significantly decreases collateral SIB dose to nearby OAR.
为局部晚期宫颈癌（LACC）病理性淋巴结的同步整合推量（SIB）剂量计划实施覆盖率（CovP）。
为实现具有中央剂量峰值和周边宽松覆盖的病理性淋巴结靶区（PTV-N）的 SIB，利用 Eclipse 治疗计划系统生成 CovP 约束条件：PTV-N D98＞90％，CTV-N D98＞100％，CTV-N D50＞101.5％的处方剂量。EBRT 剂量为 45Gy/25fx，SIB 为 55-57.5Gy，取决于近距离放疗（BT）的预期剂量。分析了 25 例先前接受治疗的 47 个接受推量的淋巴结患者。在锥形束 CT（CBCT）上勾画淋巴结，确定 GTV-N 的累积剂量和身体、骨盆和肠道接受＞50Gy（V50）的体积。
几乎所有的淋巴结（89％）都在 CBCT 上可见，并在 EBRT 期间显示出相当大的同心性退缩。98％的可见淋巴结的总 EBRT 和 BT D98 超过 57Gy。与旨在实现全 PTV-N 覆盖的治疗计划相比，CovP 显著降低了身体、骨骼和肠道的 V50（p＜0.001）。
CovP 对病理性淋巴结的 SIB 是临床可行的，并显著降低了对邻近 OAR 的旁散射 SIB 剂量。
