Dong Huiming, Pham Jonathan, Lauria Michael V, Atienza Caiden, Sloman Brett, Barry Paul, Davis Jennifer, Saracen Michael, Kishan Amar, Raldow Ann, Qi X Sharon, Hyer Daniel, Lamb James
Department of Radiation Oncology, University of California, Los Angeles, CA 90095, USA.
Department of Radiation Oncology, University of Iowa, Iowa City, IA 52242, USA.
Cancers (Basel). 2025 Aug 20;17(16):2708. doi: 10.3390/cancers17162708.
MR-guided radiation therapy (MRgRT) has rapidly evolved into an important treatment modality, with the Elekta Unity and ViewRay MRIdian systems being two major MR-linac platforms. Despite the shared concept of MRgRT, the two platforms elected different system designs that could potentially impact the dosimetric characteristics and quality of a treatment. In this study, we aim to perform a comparative dosimetric investigation between these two MR-linac systems in prostate and pancreas cancers. : Dosimetric characteristics were evaluated by retrospectively re-creating 20 clinical prostate and pancreas cases originally treated on MRIdian using the Unity system, adhering to MIRAGE and SMART clinical trial constraints. Treatment plans were re-created with matching planning images, structures, beam geometry, and dose parameters. To ensure comparison consistency, all Unity treatment plans were normalized to match the target coverage of the MRIdian counterparts, and the organ-at-risk (OAR) dose was investigated. : Most OARs' dose-volume metrics showed no statistically significant differences. For prostate patients, Unity demonstrated lower rectum V36Gy ( = 0.0095), V38Gy ( = 0.0043), V40Gy ( = 0.0469), and lower left ( = 0.0137) and right femur V20Gy ( = 0.0020). For pancreas patients, Unity plans had a lower mean liver dose ( = 0.0371). All Unity plans had a Gamma passing rate > 90%, confirming the clinical deliverability. Mean delivery times were 12.78 ± 1.68 and 13.53 ± 1.88 min for MRIdian and Unity prostate plans, respectively, and 14.58 ± 2.78 and 17.40 ± 3.77 min for MRIdian and Unity pancreas plans, respectively. : Overall, comparable treatment quality and delivery times were observed between the two platforms.
磁共振引导放射治疗（MRgRT）已迅速发展成为一种重要的治疗方式，医科达Unity和ViewRay MRIdian系统是两个主要的MR直线加速器平台。尽管MRgRT有共同的概念，但这两个平台选择了不同的系统设计，这可能会对治疗的剂量学特征和质量产生潜在影响。在本研究中，我们旨在对这两种MR直线加速器系统在前列腺癌和胰腺癌治疗中进行剂量学比较研究。：通过回顾性地重新创建20例最初在MRIdian上治疗的临床前列腺癌和胰腺癌病例，采用Unity系统，遵循MIRAGE和SMART临床试验的限制条件，对剂量学特征进行评估。使用匹配的计划图像、结构、射束几何形状和剂量参数重新创建治疗计划。为确保比较的一致性，所有Unity治疗计划均进行归一化处理，以匹配MRIdian对应计划的靶区覆盖情况，并对危及器官（OAR）剂量进行研究。：大多数OAR的剂量体积指标无统计学显著差异。对于前列腺癌患者，Unity系统显示直肠V36Gy（P = 0.0095）、V38Gy（P = 0.0043）、V40Gy（P = 0.0469）较低，左（P = 0.0137）、右股骨V20Gy（P = 0.0020）较低。对于胰腺癌患者，Unity系统计划的肝脏平均剂量较低（P = 0.0371）。所有Unity系统计划的伽马通过率>90%，证实了临床可交付性。MRIdian和Unity系统前列腺癌计划的平均交付时间分别为12.78±1.68分钟和13.53±1.88分钟，MRIdian和Unity系统胰腺癌计划的平均交付时间分别为14.58±2.78分钟和17.40±3.77分钟。：总体而言，两个平台的治疗质量和交付时间相当。
