Chitapanarux Imjai, Tharavichitkul Ekkasit, Nobnop Wannapa, Wanwilairat Somsak, Vongtama Roy, Traisathit Patrinee
Division of Therapeutic Radiology and Oncology, Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
Division of Therapeutic Radiology and Oncology, Department of Radiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
J Radiat Res. 2015 May;56(3):539-45. doi: 10.1093/jrr/rrv004. Epub 2015 Feb 26.
The aim of this study was to compare the dosimetric parameters of whole-pelvis radiotherapy (WPRT) for cervical cancer between step-and-shoot IMRT (SaS-IMRT) and Helical Tomotherapy™ (HT). Retrospective analysis was performed on 20 cervical cancer patients who received WPRT in our center between January 2011 and January 2014. SaS-IMRT and HT treatment plans were generated for each patient. The dosimetric values for target coverage and organ-at-risk (OAR) sparing were compared according to the criteria of the International Commission on Radiation Units and Measurements 83 (ICRU 83) guidelines. Differences in beam-on time (BOT) were also compared. All the PTV dosimetric parameters (D5%, D50% and D95%) for the HT plan were (statistically significantly) of better quality than those for the SaS-IMRT plan (P-value < 0.001 in all respects). HT was also significantly more accurate than SaS-IMRT with respect to the D98% and Dmean of the CTV (P-values of 0.008 and <0.001, respectively). The median Conformity Index (CI) did not differ between the two plans (P-value = 0.057). However, the Uniformity Index for HT was significantly better than that for SaS-IMRT (P-value < 0.001). The median of D50% for the bladder, rectum and small bowel were significantly lower in HT planning than SaS-IMRT (P-value < 0.001). For D2%, we found that HT provided better sparing to the rectum and bladder (P-value < 0.001). However, the median of D2% for the small bowel was comparable for both plans. The median of Dmax of the head of the left femur was significantly lower in the HT plan, but this did not apply for the head of the right femur. BOT for HT was significantly shorter than for SaS-IMRT (P-value < 0.001). HT provided highly accurate plans, with more homogeneous PTV coverage and superior sparing of OARs than SaS-IMRT. In addition, HT enabled a shorter delivery time than SaS-IMRT.
本研究旨在比较宫颈癌全盆腔放疗（WPRT）中步进式调强放疗（SaS-IMRT）与螺旋断层放疗（HT）的剂量学参数。对2011年1月至2014年1月期间在本中心接受WPRT的20例宫颈癌患者进行回顾性分析。为每位患者制定了SaS-IMRT和HT治疗计划。根据国际辐射单位与测量委员会83号（ICRU 83）指南的标准，比较了靶区覆盖和危及器官（OAR）保护的剂量学值。还比较了照射时间（BOT）的差异。HT计划的所有计划靶体积（PTV）剂量学参数（D5%、D50%和D95%）在质量上（在统计学上显著）优于SaS-IMRT计划（在各方面P值均<0.001）。就CTV的D98%和Dmean而言，HT也比SaS-IMRT显著更精确（P值分别为0.008和<0.001）。两个计划之间的中位适形指数（CI）没有差异（P值 = 0.057）。然而，HT的均匀性指数明显优于SaS-IMRT（P值<0.001）。HT计划中膀胱、直肠和小肠的D50%中位数显著低于SaS-IMRT（P值<0.001）。对于D2%，我们发现HT对直肠和膀胱的保护更好（P值<0.001）。然而，两个计划中小肠的D2%中位数相当。HT计划中左股骨头的Dmax中位数显著更低，但右股骨头并非如此。HT的BOT明显短于SaS-IMRT（P值<0.001）。与SaS-IMRT相比，HT提供了高度精确的计划，PTV覆盖更均匀，对OARs的保护更好。此外，HT能够实现比SaS-IMRT更短的治疗时间。
