MR引导的放疗系统临床应用

目的:探讨MR引导的Unity放疗系统在临床应用中的可行性。方法:临床试验入选24例患者，按治疗部位分为头颈组、胸腹组、盆腔组、脊柱组和肢体组，总共384个治疗分次。在无外置激光的情况下进行摆位，统计在线治疗流程中不同阶段所需时间和每个分次的配准误差。每周利用MR几何形变模体检测MR图像几何形变大小。并利用ArcChe...

The clinical application of magnetic resonance-guided radiotherapy

Objective To investigate the clinical feasibility of the Unity radiotherapy system guided by magnetic resonance imaging. Methods Twenty-four patients were enrolled and received a total of 384 fractions of treatment at Unity system. According to the treatment site, all patients were divided into head-neck, abdomen-thorax, pelvic, spine and limb groups. The patients were set-up without external laser. And then, the time required at different stages in online treatment process and the registration error of each fraction were separately calculated. The geometric deformations of MR images were weekly measured by using MR geometric deformation phantom. At last, the Arccheck was used to perform the dose verification of reference plan, online plan and offline plan. Results The mean duration of radiotherapy in the five groups were 29.1, 27.6, 26.6, 25.6 and 32.0min, respectively. The set-up errors in the left-right, superior-inferior and anterior-posterior direction in the five groups were:head-neck group (0.08±0.06cm, 0.16±0.13cm, 0.08±0.05cm), abdomen-thorax group (0.23±0.18cm, 0.50±0.47cm, 0.12±0.1cm), pelvic group (0.25±0.19cm, 0.32±0.25cm, 0.11±0.09cm), spine group (0.46±0.38cm, 0.26±0.26cm, 0.13±0.07cm) and limb group (0.33±0.30cm, 0.34±0.23cm, 0.08±0.06cm), respectively. In the central region, the geometric deformation of MR was less than 0.3mm, and that of the sphere with a diameter of 500mm was less than 2.1mm. The meanγ pass rate of the reference plan, online plan and offline plan were 97.92%, 97.84% and 94.58%, respectively. Conclusions MR-guided radiotherapy has great potential for clinical application, whereas the process of Unity system is relatively complex. The synergy of different departments has a great impact on the treatment, which needs further optimization.