Delivered dose can be a better predictor of rectal toxicity than planned dose in prostate radiotherapy.
Delivered dose can be a better predictor of rectal toxicity than planned dose in prostate radiotherapy.
复制标题
DOI：
10.1016/j.radonc.2017.04.008
复制
发表时间：
2017-06
期刊：
影响因子：
--
通讯作者：
Burnet NG
中科院分区：
文献类型：
--
作者：
Shelley LEA;Scaife JE;Romanchikova M;Harrison K;Forman JR;Bates AM;Noble DJ;Jena R;Parker MA;Sutcliffe MPF;Thomas SJ;Burnet NG
首次使用兆伏计算机断层扫描(MVCT)图像引导扫描计算并累积了整个前列腺癌放射治疗过程中直肠的剂量。剂量学参数与毒性相关，以检验交付剂量比计划剂量更能预测毒性的假设。VoxTox研究计划内的109名患者的每日MVCT扫描自动生成直肠壁的剂量-表面图(DSM)。根据计划CT数据，使用等效均匀剂量(EUD)和‘DSM剂量宽度’(椭圆的横向尺寸适合于离散等剂量簇)来对累积DSM和计划DSM进行参数化。用受试者操作员特征曲线分析评估与6个毒性终点的相关性。对于直肠出血，DSM剂量宽度大于70Gy时，累积剂量曲线下面积(AUC)大于计划剂量。累积65GyDSM剂量宽度产生的空间相关性最强(AUC0.664)，而累积EUD产生的AUC值最大(0.682)。对于直肠炎，累积EUD是唯一可报告的预测因子(AuC 0.673)。累积的EUD系统性地低于计划EUD。与计划的DSM相比，从累积的DSM中提取的剂量学参数与直肠出血和直肠炎的相关性更强。
For the first time, delivered dose to the rectum has been calculated and accumulated throughout the course of prostate radiotherapy using megavoltage computed tomography (MVCT) image guidance scans. Dosimetric parameters were linked with toxicity to test the hypothesis that delivered dose is a stronger predictor of toxicity than planned dose. Dose–surface maps (DSMs) of the rectal wall were automatically generated from daily MVCT scans for 109 patients within the VoxTox research programme. Accumulated-DSMs, representing total delivered dose, and planned-DSMs, from planning CT data, were parametrised using Equivalent Uniform Dose (EUD) and ‘DSM dose-width’, the lateral dimension of an ellipse fitted to a discrete isodose cluster. Associations with 6 toxicity endpoints were assessed using receiver operator characteristic curve analysis. For rectal bleeding, the area under the curve (AUC) was greater for accumulated dose than planned dose for DSM dose-widths up to 70 Gy. Accumulated 65 Gy DSM dose-width produced the strongest spatial correlation (AUC 0.664), while accumulated EUD generated the largest AUC overall (0.682). For proctitis, accumulated EUD was the only reportable predictor (AUC 0.673). Accumulated EUD was systematically lower than planned EUD. Dosimetric parameters extracted from accumulated DSMs have demonstrated stronger correlations with rectal bleeding and proctitis, than planned DSMs.