Jurkovic Ines-Ana, Kocak-Uzel Esengul, Mohamed Abdallah Sherif Radwan, Lavdas Eleftherios, Stathakis Sotirios, Papanikolaou Nikos, Fuller David C, Mavroidis Panayiotis
Department of Radiation Oncology, University of Texas Health Sciences Center at San Antonio, San Antonio, TX, USA.
Department of Radiation Oncology, Istanbul Medipol University, Istanbul, Turkey.
J Med Phys. 2018 Jan-Mar;43(1):28-40. doi: 10.4103/jmp.JMP_113_17.
This study evaluates treatment plans aiming at determining the expected impact of daily patient setup corrections on the delivered dose distribution and plan parameters in head-and-neck radiotherapy.
In this study, 10 head-and-neck cancer patients are evaluated. For the evaluation of daily changes of the patient internal anatomy, image-guided radiation therapy based on computed tomography (CT)-on-rails was used. The daily-acquired CT-on-rails images were deformedly registered to the CT scan that was used during treatment planning. Two approaches were used during data analysis ("cascade" and "one-to-all"). The dosimetric and radiobiological differences of the dose distributions with and without patient setup correction were calculated. The evaluation is performed using dose-volume histograms; the biologically effective uniform dose () and the complication-free tumor control probability () were also calculated. The dose-response curves of each target and organ at risk (OAR), as well as the corresponding curves, were calculated.
The average difference for the "one-to-all" case is 0.6 ± 1.8 Gy and for the "cascade" case is 0.5 ± 1.8 Gy. The value of was lowest for the cascade case (in 80% of the patients).
Overall, the lowest is observed in the one-to-all cases. Dosimetrically, CT-on-rails data are not worse or better than the planned data.
The differences between the evaluated "one-to-all" and "cascade" dose distributions were small. Although the differences of those doses against the "planned" dose distributions were small for the majority of the patients, they were large for given patients at risk and OAR.
本研究评估治疗计划，旨在确定头颈部放射治疗中每日患者摆位校正对所交付剂量分布和计划参数的预期影响。
本研究评估了10名头颈部癌患者。为评估患者内部解剖结构的每日变化，使用了基于轨道CT的图像引导放射治疗。将每日获取的轨道CT图像与治疗计划期间使用的CT扫描进行变形配准。数据分析过程中使用了两种方法（“级联”和“一对多”）。计算了有和没有患者摆位校正情况下剂量分布的剂量学和放射生物学差异。使用剂量体积直方图进行评估；还计算了生物等效均匀剂量（ ）和无并发症肿瘤控制概率（ ）。计算了每个靶区和危及器官（OAR）的剂量反应曲线以及相应的 曲线。
“一对多”情况的平均差异为0.6±1.8 Gy，“级联”情况的平均差异为0.5±1.8 Gy。级联情况下 的值最低（80%的患者）。
总体而言，在一对多情况下观察到最低的 。在剂量学上，轨道CT数据不比计划数据差也不比其好。
评估的“一对多”和“级联”剂量分布之间的差异很小。尽管对于大多数患者而言，这些剂量与“计划”剂量分布之间的差异很小，但对于特定的有风险患者和危及器官来说差异很大。
