Göksel Evren Ozan
Acibadem MAA University, Vocational School of Health Services, Radiotherapy Program, Istanbul, Turkey.
Acibadem Altunizade Hospital, Department of Radiation Oncology, Istanbul, Turkey.
Tech Innov Patient Support Radiat Oncol. 2025 May 24;34:100316. doi: 10.1016/j.tipsro.2025.100316. eCollection 2025 Jun.
This study aims to evaluate the dosimetric accuracy of the Lung with Respiratory (LWR) technique in the Radixact Synchrony real-time tumor tracking system using data from actual patients undergoing lung SBRT.
This retrospective study included 20 patients treated with the Synchrony LWR technique for primary lung cancer or lung metastases. Mid-ventilation breath-hold CT and 4DCT images were acquired for treatment planning and tumor motion evaluation. Gamma analysis was performed using the PTW 1500 detector. Three verification plans were generated for each patient: one for gamma analysis without motion (GAWoM), one for point dose measurement with motion (PDWM), and one for gamma analysis with motion (GAWM). Patient specific respiratory motion was simulated using a CIRS motion platform. The relationship between respiratory patterns, treatment plan parameters, and the dose delivery accuracy of the Synchrony system was evaluated using correlation analysis.
The PDWM results demonstrated a strong agreement between the planned and measured doses, with a maximum difference of less than 2%. The gamma passing rates of 3D dose measurements for all patients' Synchrony plans were found to be within the clinically acceptable level. While GAWM results were slightly lower than GAWoM results, correlation analysis revealed a strong positive relationship between the two. A moderate negative correlation was observed between the modulation factor and GAWM, similar to GAWoM. Additionally, a strong negative correlation was observed between beam-on time and both GAWoM and GAWM. Furthermore, no significant correlation was found between GAWM and respiratory pattern-related variables, including superior-inferior and lateral motion amplitude or respiratory rate per minute.
The results of the correlation analyses indicate that the dose delivery accuracy of the Synchrony LWR technique is comparable to that of static target irradiation, independent of the patient's respiratory pattern or the planning parameters used.
本研究旨在利用接受肺部立体定向放疗（SBRT）的实际患者数据，评估Radixact Synchrony实时肿瘤追踪系统中呼吸门控肺部（LWR）技术的剂量学准确性。
这项回顾性研究纳入了20例接受Synchrony LWR技术治疗原发性肺癌或肺转移瘤的患者。采集了呼气末屏气CT和4DCT图像用于治疗计划制定和肿瘤运动评估。使用PTW 1500探测器进行伽马分析。为每位患者生成三个验证计划：一个用于无运动伽马分析（GAWoM），一个用于有运动时的点剂量测量（PDWM），一个用于有运动伽马分析（GAWM）。使用CIRS运动平台模拟患者特定的呼吸运动。采用相关性分析评估呼吸模式、治疗计划参数与Synchrony系统剂量输送准确性之间的关系。
PDWM结果显示计划剂量与测量剂量之间高度一致，最大差异小于2%。所有患者Synchrony计划的3D剂量测量伽马通过率均在临床可接受水平内。虽然GAWM结果略低于GAWoM结果，但相关性分析显示两者之间存在强正相关。观察到调制因子与GAWM之间存在中度负相关，与GAWoM类似。此外，观察到照射时间与GAWoM和GAWM均存在强负相关。此外，未发现GAWM与呼吸模式相关变量之间存在显著相关性，包括上下和左右运动幅度或每分钟呼吸频率。
相关性分析结果表明，Synchrony LWR技术的剂量输送准确性与静态靶区照射相当，与患者的呼吸模式或所使用的计划参数无关。
