INTER- AND INTRAFRACTION PATIENT POSITIONING UNCERTAINTIES FOR INTRACRANIAL RADIOTHERAPY: A STUDY OF FOUR FRAMELESS, THERMOPLASTIC MASK-BASED IMMOBILIZATION STRATEGIES USING DAILY CONE-BEAM CT
INTER- AND INTRAFRACTION PATIENT POSITIONING UNCERTAINTIES FOR INTRACRANIAL RADIOTHERAPY: A STUDY OF FOUR FRAMELESS, THERMOPLASTIC MASK-BASED IMMOBILIZATION STRATEGIES USING DAILY CONE-BEAM CT
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DOI：
10.1016/j.ijrobp.2010.06.022
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发表时间：
2011-05-01
影响因子：
7
通讯作者：
Kleinberg, Lawrence
中科院分区：
文献类型：
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作者：
Tryggestad, Erik;Christian, Matthew;Kleinberg, Lawrence
目的：确定无框架热塑面罩固定术是否适用于影像引导下的颅底放射外科手术。方法与材料：对颅内肿瘤患者的锥束CT定位数据进行治疗前后每日扫描。所研究的系统是：(1)S型IMRT(纯头垫)面罩(CIVCO)；(2)带头垫的单幅面罩(CIVCO)，配合BlueBag身体固定器(医用智能)；(3)S式头肩垫头肩面罩(CIVCO)；(4)与以前相同，配上牙套。比较指标为平移幅度和平均旋转角；计算系统的节间、随机节间和随机节内定位误差。对于策略1-4，对组间变异性的分析包括20、9、81和11名患者的数据，而对组内变异性的分析包括7、9、16和8名患者的子集。结果：固定系统4具有最好的整体准确性和稳定性。平均节段间移位(+/-SD)分别为2.3(+/-1.4)、2.2(+/-1.1)、2.7(+/-1.5)和2.1(+/-1.0)mm，节段内运动分别为1.1(+/-1.2)、1.1(1.1)、0.7(+/-0.9)和0.7(+/-0.8)mm。虽然片内运动不是纯粹随机的，但片内运动与治疗时间之间没有明显的相关性。结论：我们发现所有研究的无框热塑面罩系统都是图像引导的颅内放射外科的可行解决方案。如果有理想的放射计划和靶向系统，加上每日的前处理校正，1毫米的对称PTV边缘可能是足够的。(C)2011年爱思唯尔公司。
Purpose: To determine whether frameless thermoplastic mask-based immobilization is adequate for image-guided cradinal radiosurgery.Methods and Materials: Cone-beam CT localization data from patients with intracranial tumors were studied using daily pre- and posttreatment scans. The systems studied were (1) Type-S IMRT (head only) mask (Civco) with head cushion; (2) Uni-Frame mask (Civco) with head cushion, coupled with a BlueBag body immobilizer (Medical Intelligence); (3) Type-S head and shoulder mask with head and shoulder cushion (Civco); (4) same as previous, coupled with a mouthpiece. The comparative metrics were translational shift magnitude and average rotation angle; systematic inter-, random inter-, and random intrafraction positioning error was computed. For strategies 1-4, respectively, the analysis for interfraction variability included data from 20, 9, 81, and 11 patients, whereas that for intrafraction variability included a subset of 7, 9, 16, and 8 patients. The results were compared for statistical significance using an analysis of variance test.Results: Immobilization system 4 provided the best overall accuracy and stability. The mean interfraction translational I shifts (+/- SD) were 2.3 (+/- 1.4), 2.2 (+/- 1.1), 2.7 (+/- 1.5), and 2.1 (+/- 1.0) mm whereas intrafraction motion was 1.1 (+/- 1.2), 1.1 ( 1.1), 0.7 (+/- 0.9), and 0.7 (+/- 0.8) mm for devices 1-4, respectively. No significant correlation between intrafraction motion and treatment time was evident, although intrafraction motion was not purely random.Conclusions: We find that all frameless thermoplastic mask systems studied are viable solutions for image-guided intracranial radiosurgery. With daily pretreatment corrections, symmetric PTV margins of 1 mm would likely be adequate if ideal radiation planning and targeting systems were available. (C) 2011 Elsevier Inc.