CAJ | 학술논문

目的：比较对直肠癌术前患者应用固定野调强（ fixed-field intensity-modulated radiotherapy， FF-IMRT）和容积调强（volumetric modulated arc therapy， VMAT）两种计划方式进行术前放射治疗的剂量学差异。方法选择15例直肠癌术前进行调强放疗的患者行CT模拟定位，勾画靶区及危及器官，对同一CT图像设计FF-IMRT计划和VMAT计划。评估靶区及危及器官的剂量分布。结果 VMAT计划组和FF-IMRT计划组靶区覆盖度均能满足处方剂量要求。与FF-IMRT计划组相比， VMAT计划组计划靶区（planning target volume， PTV）105％覆盖度、 Dmean及Dmax均增加（P＝0.011， P＝0.017， P＝0.006），适形度指数减低（P＝0.008），而均匀性指数差异无统计学意义（P＝0.193）。与FF-IMRT计划组相比， VMAT计划组膀胱V50增加约15％（ P＝0.009）， Dmax 平均值增加0.7 Gy （ P ＝0.003）；小肠 V30降低10％（ P ＝0.004）， Dmax平均值增加0.9 Gy （P＝0.000）；骨髓 V10、 V30、 V40分别降低2％、10％、10％（P＝0.000， P＝0.000， P＝0.000）， Dmean平均值降低1.7 Gy （P＝0.000）；左右股骨头D5分别降低3.2 Gy、2.4 Gy （P＝0.000， P＝0.000）；全身V10、 V20、 V30、 V40也明显降低（P＝0.003， P＝0.000， P＝0.000， P＝0.004）。 VMAT计划组较FF-IMRT计划组机器跳数（monitor units， MU）平均值减少50％（P＝0.000）。结论直肠癌术前患者采用VMAT技术，可以获得等同于或优于FF-IMRT计划的剂量分布，患者治疗时间明显缩短， MU明显降低。
목적：비교대직장암술전환자응용고정야조강（ fixed-field intensity-modulated radiotherapy， FF-IMRT）화용적조강（volumetric modulated arc therapy， VMAT）량충계화방식진행술전방사치료적제량학차이。방법선택15례직장암술전진행조강방료적환자행CT모의정위，구화파구급위급기관，대동일CT도상설계FF-IMRT계화화VMAT계화。평고파구급위급기관적제량분포。결과 VMAT계화조화FF-IMRT계화조파구복개도균능만족처방제량요구。여FF-IMRT계화조상비， VMAT계화조계화파구（planning target volume， PTV）105％복개도、 Dmean급Dmax균증가（P＝0.011， P＝0.017， P＝0.006），괄형도지수감저（P＝0.008），이균균성지수차이무통계학의의（P＝0.193）。여FF-IMRT계화조상비， VMAT계화조방광V50증가약15％（ P＝0.009）， Dmax 평균치증가0.7 Gy （ P ＝0.003）；소장 V30강저10％（ P ＝0.004）， Dmax평균치증가0.9 Gy （P＝0.000）；골수 V10、 V30、 V40분별강저2％、10％、10％（P＝0.000， P＝0.000， P＝0.000）， Dmean평균치강저1.7 Gy （P＝0.000）；좌우고골두D5분별강저3.2 Gy、2.4 Gy （P＝0.000， P＝0.000）；전신V10、 V20、 V30、 V40야명현강저（P＝0.003， P＝0.000， P＝0.000， P＝0.004）。 VMAT계화조교FF-IMRT계화조궤기도수（monitor units， MU）평균치감소50％（P＝0.000）。결론직장암술전환자채용VMAT기술，가이획득등동우혹우우FF-IMRT계화적제량분포，환자치료시간명현축단， MU명현강저。
Objective To compare the dosimetric characteristics of preoperative volumetric modulated arc therapy ( VMAT) and fixed-field intensity-modulated radiotherapy ( FF-IMRT) for rectal cancer .Methods The CT images of 15 patients with rectal cancer were transferred into Eclipse planning system .FF-IMRT and VMAT plans were optimized on an Eclipse treatment planning system using beam data generated for Varian Trilogy linear accelerator .Same institutional dose-volume constraints for rectal cancer were used in both techniques .Targets and organs at risk were evaluated .Results The target volume coverage could meet the requirement of described dosage in both VMAT plan group and FF-IMRT plan group .Compared with the FF-IMRT plan group , the plan-ning target volume ( PTV) 105% ( PTV105%) coverage, Dmean, and Dmax significantly increased in the VMAT plan group ( P=0.011, P=0.017, and P=0.006, respectively), the radiation conformity index (CI) significantly decreased ( P=0.008 ) , and the homogeneity index showed no significant difference ( P=0.193 ) . Compared with the FF-IMRT plan group , the V50 of the bladder in the VMAT plan group was increased by about 15%( P=0.009 ) , and the Dmax increased by 0.7 Gy ( P=0.003 );the V30 of the small intestine decreased by 10% (P=0.004), and the Dmax was increased by 0.9 Gy (P=0.000); the V10, V30, and V40 of the bone marrow reduced by 2%, 10%, and 10%( P=0.000 , P=0.000 , and P=0.000 ) , and the Dmean re-duced by 1.7 Gy ( P=0.000 );the D5 of the left and right femoral heads reduced by 3.2 Gy and 2.4 Gy ( P=0.000 , P=0.000 ); the V10 , V20 , V30 , and V40 of the body also significantly decreased ( P=0.003 , P=0.000 , P=0.000 , and P=0.004 ) .The VMAT group also had significantly lower number of monitor units ( MU) when compared with the FF-IMRT plan group ( P=0.000 ) .Conclusions In patients with rectal canc-er, preoperative VMAT can achieve equivalent or superior dose distribution compared with the FF -IMRT.In addi-tion, VMAT can increase the number of patients treated per hour and reduce waiting time by shortening treatment time and reducing treatment MU .