CAJ | 학술논문

目的分析碘油标记的肝癌图像对有无图像引导放疗(IGRT)中不同配准方法及靶区外放范围的影响.方法 5例经动脉灌注化疗栓塞(TACE)后放疗的肝癌患者,在医科达IGRT联合主动呼吸控制(ABC)系统下,每日治疗前用锥形束CT (CBCT)采集图像.根据靶区及邻近器官进行治疗计划CT图像和CBCT容积图像配准,记录左右、上下、前后方向偏移值(CBCT1),并校正摆位误差；纠正后再次CBCT扫描与CT图像配准(CBCT2);治疗结束后,再次CBCT扫描与CT图像配准(CBCT3).用SPSS软件计算CTV-PTV的外放边界,对CBCT1、CBCT2、CBCT3比较结果行配对t检验.结果 CBCT1和CBCT2及CBCT3在左右、上下、前后方向偏移值不同,分别为0.254、-0.612、0.314 cm和0.020、0.014、-0.064 cm及-0.004、0.042、-0.040 cm.CTV-PTV外放边界无IGRT时左右、上下、前后方向分别为0.96、0.96、0.83 cm,有IGRT时为0.67、0.68、0.58 cm.离线分析放疗过程中CBCT下碘油图像形态变化发现,即使在靶区(碘油)精确配准下,肝脏在上下方向、椎体在3个方向上仍有很大偏移值.结论 IGRT技术带来的CTV -PTV外放减小约3 mm.内靶区无标记物患者,CTV -PTV外放应将肿瘤上下方向误差及椎体误差考虑在内.配准时如果单纯以肝缘图像为参考配准点,图像配准将会有很大不确定性.
목적 분석전유표기적간암도상대유무도상인도방료(IGRT)중불동배준방법급파구외방범위적영향.방법 5례경동맥관주화료전새(TACE)후방료적간암환자,재의과체IGRT연합주동호흡공제(ABC)계통하,매일치료전용추형속CT (CBCT)채집도상.근거파구급린근기관진행치료계화CT도상화CBCT용적도상배준,기록좌우、상하、전후방향편이치(CBCT1),병교정파위오차；규정후재차CBCT소묘여CT도상배준(CBCT2);치료결속후,재차CBCT소묘여CT도상배준(CBCT3).용SPSS연건계산CTV-PTV적외방변계,대CBCT1、CBCT2、CBCT3비교결과행배대t검험.결과 CBCT1화CBCT2급CBCT3재좌우、상하、전후방향편이치불동,분별위0.254、-0.612、0.314 cm화0.020、0.014、-0.064 cm급-0.004、0.042、-0.040 cm.CTV-PTV외방변계무IGRT시좌우、상하、전후방향분별위0.96、0.96、0.83 cm,유IGRT시위0.67、0.68、0.58 cm.리선분석방료과정중CBCT하전유도상형태변화발현,즉사재파구(전유)정학배준하,간장재상하방향、추체재3개방향상잉유흔대편이치.결론 IGRT기술대래적CTV -PTV외방감소약3 mm.내파구무표기물환자,CTV -PTV외방응장종류상하방향오차급추체오차고필재내.배준시여과단순이간연도상위삼고배준점,도상배준장회유흔대불학정성.
Objective To analyze the transitional shifts between with different sets of cone-beam computed tomography (CBCT) and the planning CT for liver cancer patients,and calculate the margins from clinical target volume (CTV) to the planning target volume (PTV) with and without image guided radiotherapy (IGRT).Methods Five liver cancer patients received radiotherapy after transcatheter arterial chemoembolization (TACE).The first CBCT images (CBCT1) were obtained with Elekta CBCT plus active breathing control (ABC) system before treatment.The second CBCT images (CBCT2 ) were obtained after correcting the set-up errors and the third CBCT images ( CBCT3 ) were obtained after treatment.The CBCT images were registered and matched with the planning CT images using lipiodol as a direct surrogate for target localization.The PTV margins were calculated by comparing the shift between planning CT and CBCT according to formula M =2.5 ( Σ doctor2 + Σ set-up2 + Σ transter2 )1/2.Paired t-test was used to compare the differences between the results from CBCT1,CBCT2 and CBCT3. Results The average transition shifts in the left-right ( LR),superior-inferior (SI) and anterior-posterior (AP) directions were 0.254,-0.612,0.314 cm between planning CT and CBCT1 ;were 0.020,0.014,-0.064 cm between planning CT and CBCT2 ;and they were -0.004,0.042,-0.040 cm between planning CT and CBCT3.The PTV margins were LR 0.96 cm,SI 0.96 cm and AP 0.83 cm without IGRT,and LR 0.67 cm,SI 0.68 cm and AP 0.58 cm with IGRT.Conclusions The PTV margins can be reduced by 3 mm with IGRT for liver cancer using lipiodol as a direct surrogate for target localization.