Kinhikar Rajesh A, Jamema Swamidas V, Pai Rajeshri, Zubin Master, Gupta Tejpal, Dhote Deepak S, Deshpande Deepak D, Shrivastava Shyam K, Sarin Rajiv
Department of Medical Physics, Tata Memorial Hospital, Parel, Mumbai, Department of Radiation Oncology, Tata Memorial Hospital, Parel, Mumbai, India.
J Med Phys. 2009 Jan;34(1):23-30. doi: 10.4103/0971-6203.48717.
A Helical Tomotherapy (HT) Hi-Art II machine, Hi ART (TomoTherapy, Inc., Madison, WI, USA) was installed at our center in July 2007, and was the first machine in India. Image-guided HT is a new modality for delivering intensity modulated radiotherapy (IMRT). Dosimetric tests done include (a) primary beam alignment (b) secondary beam alignment (c) water tank measurements (profiles and depth doses) (d) dose rate measurements (e) IMRT verification, and (f) Mega voltage Computed Tomography (MVCT) dose. Primary and secondary beam alignment revealed an acceptable linear accelerator (linac) alignment in both X and Y axes. In addition, it was observed that the beam was aligned in the same plane as gantry and the jaws were not twisted with respect to gantry. The rotational beam stability was acceptable. Multi-leaf collimators (MLC) were found to be stable and properly aligned with the radiation plane. The jaw alignment during gantry rotation was satisfactory. Transverse and longitudinal profiles were in good agreement with the "Gold" standard. During IMRT verification, the variation between the measured and calculated dose for a particular plan at the central and off-axis was found to be within 2% and 1mm in position, respectively. The dose delivered during the TomoImage scan was found to be 2.57 cGy. The Helical Tomotherapy system is mechanically stable and found to be acceptable for clinical treatment. It is recommended that the output of the machine should be measured on a daily basis to monitor the fluctuations in output.
2007年7月，一台螺旋断层放射治疗（HT）Hi-Art II型设备（Hi ART，TomoTherapy公司，美国威斯康星州麦迪逊市）在我们中心安装，这是印度的第一台此类设备。图像引导螺旋断层放射治疗是一种用于实施调强放射治疗（IMRT）的新方式。所进行的剂量学测试包括：（a）原射线校准；（b）散射线校准；（c）水箱测量（剂量分布曲线和深度剂量）；（d）剂量率测量；（e）调强放射治疗验证；以及（f）兆伏级计算机断层扫描（MVCT）剂量。原射线和散射线校准显示在X轴和Y轴上直线加速器（直线加速器）校准均可接受。此外，观察到射线与机架在同一平面校准，并且准直器相对于机架没有扭曲。旋转射线稳定性可接受。发现多叶准直器（MLC）稳定且与辐射平面校准良好。机架旋转期间准直器校准令人满意。横向和纵向剂量分布曲线与“金”标准高度一致。在调强放射治疗验证期间，发现特定计划在中心和离轴处测量剂量与计算剂量之间的差异分别在2%以内和位置偏差1毫米以内。TomoImage扫描期间输送的剂量为2.57厘戈瑞。螺旋断层放射治疗系统机械稳定，临床治疗可接受。建议每天测量机器输出以监测输出波动情况。
