CAJ | 학술논문

目的采用滑轨CT系统测量立体定向放射治疗(SBRT)过程中肺部肿瘤分次间中心位置移动.方法 2011年10月至2014年5月,共有34例肺部肿瘤在CT-vision加速器接受SBRT.治疗前采用螺旋CT扫描进行验证.采用骨性配准将验证CT与定位CT融合并勾画每次治疗前的GTV,得出分次间肿瘤中心位置移动并以各方向位移及向量位移表示.结果 34例肺部肿瘤向量位移为(5.2±3.1)mm,在腹背、头脚及左右方向中心位置移动分别为(-0.69±4.47)mm、(0.23±3.13)mm和(0.36±2.36)mm.然而,任一方向中心位置移动的绝对值≥5 mm在左右方向占3.3％,头脚方向占10.5％,腹背方向占23.5％.结论尽管分次间肺部肿瘤平均中心位置移动在3个方向上均较小,但超过5 mm的次数约占1/3,这提示PTV外扩的边界不够,尤其是在腹背方向.
목적 채용활궤CT계통측량입체정향방사치료(SBRT)과정중폐부종류분차간중심위치이동.방법 2011년10월지2014년5월,공유34례폐부종류재CT-vision가속기접수SBRT.치료전채용라선CT소묘진행험증.채용골성배준장험증CT여정위CT융합병구화매차치료전적GTV,득출분차간종류중심위치이동병이각방향위이급향량위이표시.결과 34례폐부종류향량위이위(5.2±3.1)mm,재복배、두각급좌우방향중심위치이동분별위(-0.69±4.47)mm、(0.23±3.13)mm화(0.36±2.36)mm.연이,임일방향중심위치이동적절대치≥5 mm재좌우방향점3.3％,두각방향점10.5％,복배방향점23.5％.결론 진관분차간폐부종류평균중심위치이동재3개방향상균교소,단초과5 mm적차수약점1/3,저제시PTV외확적변계불구,우기시재복배방향.
Objective To determine interfractional changes of tumor centroid position during stereotactic body radiation therapy (SBRT) for lung cancer using image-guided computed tomography (CT) on-rail system.Methods A total of 34 tumors were treated by SBRT using an integrated CT-LIN-AC system form octoper 2011 to May 2014.The fast helical CT scans acquired for treatment setup were retrospectively registered with simulation CT scans on the basis of the bony reference region of interest (ROI).Then,the gross target volume (GTV) was contoured on all verification CT scans and compared to the initial GTV in treatment plan.Interfractional variation of tumor centroid position was evaluated for both directional shift and vector shift.Results The mean magnitude of vector shift was (5.2 ±3.1) mm.The mean interfractional variations of tumor centroid position were (-0.69 ± 4.47) mm in anterior-posterior (AP) direction,(0.23 ±3.13) mm in superior-inferior (SI) direction and (0.36 ± 2.36)mm in right-left(RL) direction.However,interfractional variations (≥5 mm) were observed from any direction 3.3％ in RL direction,10.5％ in SI direction and 23.5％ in AP direction.Tumor volume did not decrease significantly during the SBRT treatment (P =0.078).Conclusions While the mean interfractional variations of tumor centroid position were in three directions,the vantions which were more than 5 mm took about one third,indicating additional margin for PTV were not enongh,especially in the AP direction.