Moliner Gilles, Sorro Lise, Verstraet Rodolfe, Daviau Paul Alexandre, Casas Mélanie, Piron Bérengère, Dubois Karine, Debrigode Charles, Barrau Corinne, Bons Françoise, Greffier Joël
Department of Radiotherapy, Nîmes University Hospital, Nîmes Cedex, France.
Medical Physics Unit, Nîmes University Hospital, Nîmes Cedex, France.
J Appl Clin Med Phys. 2018 Nov;19(6):133-139. doi: 10.1002/acm2.12460. Epub 2018 Oct 19.
To assess the efficiency of combined use of ArcCheck detector (AC) and portal dosimetry (PDIP) for delivery quality assurance of head and neck and prostate volumetric-modulated arc therapy.
Measurement processes were studied with the Gamma index method according to three analysis protocols. The detection sensitivity to technical errors of each individual or combined measurement processes was studied by inserting collimator, dose and MLC opening error into five head and neck and five prostate initial treatment plans. A total of 220 plans were created and 660 analyses were conducted by comparing measurements to error free planned dose matrix.
For head and neck localization, collimator errors could be detected from 2° for AC and 3° for PDIP. Dose and MLC errors could be detected from 2% and 0.5 mm for AC and PDIP. Depending on the analysis protocol, the detection sensitivity of total simulated errors ranged from 54% to 88% for AC vs 40% to 74% for PDIP and 58% to 92% for the combined process. For the prostate localization, collimator errors could be detected from 4° for AC while they could not be detected by PDIP. Dose and MLC errors could be detected from 3% and 0.5 mm for AC and PDIP. The detection sensitivity of total simulated errors ranged from 30% to 56% for AC vs 16% to 38% for PDIP and 30% to 58% for combined process.
The combined use of the two measurement processes did not statistically improve the detectability of technical errors compared to use of single process.
评估ArcCheck探测器（AC）和射野剂量成像（PDIP）联合使用对头颈部及前列腺容积调强弧形治疗的剂量输送质量保证的效率。
根据三种分析方案，采用伽马指数法研究测量过程。通过将准直器、剂量和多叶准直器（MLC）开口误差插入五个头颈部和五个前列腺初始治疗计划中，研究每个单独或联合测量过程对技术误差的检测灵敏度。共创建了220个计划，并通过将测量结果与无误差计划剂量矩阵进行比较进行了660次分析。
对于头颈部定位，AC在2°时可检测到准直器误差，PDIP在3°时可检测到。AC和PDIP在剂量和MLC误差分别为2%和0.5 mm时可检测到。根据分析方案，AC对总模拟误差的检测灵敏度范围为54%至88%，PDIP为40%至74%，联合过程为58%至92%。对于前列腺定位，AC在4°时可检测到准直器误差，而PDIP无法检测到。AC和PDIP在剂量和MLC误差分别为3%和0.5 mm时可检测到。AC对总模拟误差的检测灵敏度范围为30%至56%，PDIP为16%至38%，联合过程为30%至58%。
与使用单一测量过程相比，两种测量过程联合使用在统计学上并未提高对技术误差的可检测性。
