Upreti Ritu Raj, Budrukkar Ashwini, Wadasadawala Tabassum, Misra Shagun, Gurram Lavanya, Pathak Rima, Deshpande Deepak D
Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai.
Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai.
J Contemp Brachytherapy. 2017 Apr;9(2):139-145. doi: 10.5114/jcb.2017.66027. Epub 2017 Feb 14.
To investigate the interobserver variations in delineation of lumpectomy cavity (LC) and clinical target volume (CTV), and its impact on irradiated volume in accelerated partial breast irradiation using intraoperative multicatheter brachytherapy.
Delineation of LC and CTV was done by five radiation oncologists on planning computed tomography (CT) scans of 20 patients with intraoperative interstitial breast implant. Cavity visualization index (CVI), four-point index ranging from (0 = poor) to (3 = excellent) was created and assigned by observers for each patient. In total, 200 contours for all observers and 100 treatment plans were evaluated. Spatial concordance (conformity index, CI, and CI), average shift in the center of mass (COM), and ratio of maximum and minimum volumes (V/V) of LC and CTV were quantified among all observers and statistically analyzed. Variation in active dwell positions (0.5 cm step) for each catheter, total reference air kerma (TRAK), volume enclosed by prescription isodose (V) among observers and its spatial concordance were analyzed.
The mean ± SD CI of LC and CTV was 0.54 ± 0.09, and 0.58 ± 0.08, respectively. Conformity index tends to increase, shift in COM and V/V decrease significantly ( < 0.05), as CVI increased. Out of total 309 catheters, 29.8% catheters had no change, 29.8% and 17.5% catheters had variations of 1 and 2 dwell positions (0.5 cm and 1 cm), respectively. 9.3% catheters shown variations ≥ 10 dwell positions (5 cm). The mean ± SD CI of V was 0.75 ± 0.11. The mean observed V/V of prescription isodose and TRAK was 1.18 (range, 1.03 to 1.56) and 1.11 (range, 1.03 to 1.35), respectively.
Interobserver variability in delineation of target volume was found to be significantly related to CVI. Smaller variability was observed with excellent visualization of LC. Interobserver variations showed dosimetric impact on irradiation of breast tissue volume with prescription dose.
研究在术中多导管近距离放射治疗的加速部分乳腺照射中，观察者之间在勾画乳房肿瘤切除腔（LC）和临床靶区（CTV）方面的差异，及其对照射体积的影响。
由五位放射肿瘤学家对20例术中进行间质乳腺植入患者的计划计算机断层扫描（CT）图像进行LC和CTV的勾画。观察者为每位患者创建并分配了腔可视化指数（CVI），这是一个从（0 = 差）到（3 = 优）的四点指数。总共评估了所有观察者的200个轮廓和100个治疗计划。对所有观察者之间的空间一致性（符合指数，CI，和CI）、质心（COM）的平均偏移以及LC和CTV的最大和最小体积比（V/V）进行了量化并进行统计分析。分析了每个导管的活性驻留位置（0.5 cm步长）的变化、总参考空气比释动能（TRAK）、观察者之间处方等剂量线所包围的体积（V）及其空间一致性。
LC和CTV的平均±标准差CI分别为0.54±0.09和0.58±0.08。随着CVI增加，符合指数趋于增加，COM偏移和V/V显著降低（<0.05）。在总共309根导管中，29.8%的导管没有变化，29.8%和17.5%的导管分别有1个和2个驻留位置（0.5 cm和1 cm）的变化。9.3%的导管显示变化≥10个驻留位置（5 cm）。V的平均±标准差CI为0.75±0.11。处方等剂量线和TRAK的平均观察到的V/V分别为1.18（范围，1.03至1.56）和1.11（范围，1.03至1.35）。
发现观察者之间在靶区勾画方面的变异性与CVI显著相关。在LC可视化良好的情况下观察到较小的变异性。观察者之间的差异显示出对用处方剂量照射乳腺组织体积有剂量学影响。
