INTERFRACTIONAL UNCERTAINTY IN THE TREATMENT OF PANCREATIC CANCER WITH RADIATION
INTERFRACTIONAL UNCERTAINTY IN THE TREATMENT OF PANCREATIC CANCER WITH RADIATION
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DOI：
10.1016/j.ijrobp.2009.06.029
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发表时间：
2010-02-01
影响因子：
7
通讯作者：
Chang, Daniel T.
中科院分区：
文献类型：
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作者：
Jayachandran, Priya;Minn, A. Yuriko;Chang, Daniel T.
方法与材料：5例在斯坦福大学(Stanford，CA)接受明确的调强放射治疗的胰腺癌患者，均接受了基准粒子植入和呼吸门控瓦里安三联系统(Varian，Palo Alto，CA)治疗。每日进行正交千伏成像以验证患者的位置，并进行初始等中心偏移以匹配骨骼解剖。接下来，在透视引导下进行最后一次转移至基准种子，以在呼吸机门控阶段确定胰腺肿瘤的位置。测量左(+)-右(-)、前(-)-后(+)和上(+)-下(-)三个轴的所有移位，并根据这些值计算总体的分割间肿瘤移动。结果：总共分析了140个分割。移位至骨性解剖后，前后位、左右位和上下位的平均绝对移位分别为1.6 mm(第95个百分位数，7 mm；范围0~9 mm)、1.8 mm(第95个百分位数，7 mm；0~13 mm)和4.1 mm(第95个百分位数，12 mm；范围1~19 mm)。平均分数向量移位距离为5.5 rum(第95百分位数，14.5 mm；范围0~19.3 mm)。在140个部位中，有28个部位(20%)在对准骨骼解剖后不需要基准点移位。结论：使用呼吸门控放射治疗胰腺肿瘤时，对齐骨骼解剖后仍存在相当大的不确定性。在放射治疗中，骨解剖与肿瘤位置匹配的比例仅为20%。如果在没有植入基准的情况下，骨性对齐与呼吸门控联合使用，治疗边际需要考虑这种不确定性。(C)2010年爱思唯尔公司。
Purpose: To compare the interfractional variation in pancreatic tumor position using bony anatomy and implanted fiducial markers.Methods and Materials: Five consecutively treated patients with pancreatic adenocarcinoma who received definitive intensity-modulated radiation therapy at Stanford University (Stanford, CA) underwent fiducial seed placement and treatment on the Varian Trilogy system (Varian, Palo Alto, CA) with respiratory gating. Daily orthogonal kilovoltage imaging was performed to verify patient positioning, and isocenter shifts were made initially to match bony anatomy. Next, a final shift to the fiducial seeds was made under fluoroscopic guidance to confirm the location of the pancreatic tumor during the respirator), gated phase. All shifts were measured along three axes, left (+)-right (-), anterior (-)-posterior (+), and superior (+)-inferior (-), and the overall interfractional tumor movement was calculated based on these values.Results: A total of 140 fractions were analyzed. The mean absolute shift to fiducial markers after shifting to bony anatomy was 1.6 mm (95th percentile, 7 mm; range, 0-9 mm), 1.8 mm (95th percentile, 7 mm; range, 0-13 mm), and 4.1 mm (95th percentile, 12 mm; range, (1-19 mm) in the anterior-posterior, left-right, and superior-inferior directions, respectively. The mean interfractional vector shift distance was 5.5 rum (95th percentile, 14.5 mm; range, 0-19.3 mm). In 28 of 140 fractions (20%) no fiducial shift was required after alignment to bony anatomy.Conclusions: There is substantial residual uncertainty after alignment to bony anatomy when radiating pancreatic tumors using respiratory gating. Bony anatomy matched tumor position in only 20% of the radiation treatments. If bony alignment is used in conjunction with respiratory gating without implanted fiducials, treatment margins need to account for this uncertainty. (C) 2010 Elsevier Inc.