Dynamic conical conformal radiotherapy using a C-arm mounted accelerator and its treatment planning software

该研究的目的是改善使用c臂安装加速器旋转适形放疗（RCRT）的剂量分布。直线机头被设计为沿着c臂移动的最大角度为60度（从垂直位置到龙门）。同时旋转的龙门架创造了一个动态的锥形辐照技术。动态锥形适形放射治疗（Dyconic CRT）是将多叶准直器（MLC）连续运动技术相结合而发展起来的。用膜密度法测量了幻影中的剂量分布，并与常规RCRT进行了比较。同时也给出了实际放射治疗患者的剂量分布。动态阴极射线管实现了精确的非共面射束，无需工作台旋转。此外，Dyconic CRT的专门治疗计划软件在市售RTP计算机上完成。测量结果表明，与常规RCRT相比，Dyconic CRT实现了三维比例剂量梯度。Dyconic CRT矢状方向均匀剂量用30度楔形补偿。该技术克服了RCRT在剂量分布上的缺点。

The aim of the study was to improve dose distribution with rotational conformal radiotherapy (RCRT) using a C-arm mounted accelerator. The linac head was designed to move along the C-arm with a maximum angle of 60 degrees (from a vertical position toward the gantry). Simultaneous rotation of the gantry creates a dynamic conical irradiation technique. Dynamic conical conformal radiation therapy (Dyconic CRT) was developed by combining the technique with continuous motion of multi-leaf collimator (MLC). Dose distributions were measured in phantoms using film densitometry and compared with conventional RCRT. Dose distributions in actual radiation therapy patients are also presented. Dyconic CRT actualized precise non-coplanar beam entry without table rotation. In addition, a specialized treatment planning software for Dyconic CRT was completed on a commercially available RTP computer. The measurements showed that three-dimensionally proportional dose gradient was achieved with Dyconic CRT, when compared to that with conventional RCRT. Dose in homogeneity in the sagittal direction with Dyconic CRT was compensated by use of 30-degree wedge. Drawback of RCRT in dose distribution was overcome with the present technique.