A dosimetric study of different field numbers in intensity-modulated radiotherapy for cervical cancer. [J]. Journal of Southwest Medical University 44(4):338-344(2021)
DOI:
A dosimetric study of different field numbers in intensity-modulated radiotherapy for cervical cancer. [J]. Journal of Southwest Medical University 44(4):338-344(2021) DOI: 10.3969/j.issn.2096-3351.2021.04.006.
A dosimetric study of different field numbers in intensity-modulated radiotherapy for cervical cancer
Objective To investigate the dosimetric characteristics of different field numbers in intensi⁃ty-modulated radiotherapy for cervical cancer. Methods A total of 20 patients with cervical cancer who received in⁃tensity-modulated radiotherapy in our hospital from August to December 2020 were enrolled;and two intensi⁃ty-modulated radiotherapy plans with 5 and 7 fields were designed for each patient. The incidence angles were 45°, 115°,180°,245°,and 315°in the plan with 5 fields(Plan A)and were 0°,50°,100°,150°,210°,260°,and 310°in the plan with 7 fields(Plan B). The equivalent uniform dose optimization method was used;and when the cost val⁃ues of the bladder;the rectum;and the small intestine were not equal to zero and the dose of the pelvis was mini⁃mized so that the 100% isodose contour covered 95% of the target volume;the target area and the organs at risk were compared in terms of dosimetry. Results Plan B had significantly better conformity index and homogeneity in⁃dex of the planning target than Plan A(P<0.001). There were no significant differences in V10 and V50 of the organs at risk(rectum and bladder)between the two plans(P>0.05). Compared with Plan A,Plan B had significantly bet⁃ter V20,V30,V40,and Dmean of the rectum;V20,V30,V40,and Dmean of the bladder,V30,V40,V50,and Dmean of the small intes⁃tine and V20,V30,V40,V50,and Dmean of the pelvis;while Plan A had significantly better V10 and V20 of the small intes⁃tine and V10 of the pelvis than Plan B(P<0.05). Compared with Plan B;Plan A had a significantly lower number of monitor units and a significantly shorter beam-on time than Plan B(P<0.001). Conclusion Both plans can meet clinical needs and have their own advantages in the high-and low-dose areas of the small intestine and the pelvis;however,considering the association with radiation injury and the results of dosimetric analysis,Plan B is more suit⁃able for clinical application.
关键词
不同射野数目等效均匀剂量优化法宫颈癌调强放疗计划剂量学
Keywords
Field numberEquivalent uniform dose optimizationIntensity-modulated radiothera⁃py for cervical cancerDosimetric study