Department of Radiation Oncology, University of California, Davis Health System, Sacramento, CA, USA.
J Appl Clin Med Phys. 2010 Sep 7;11(4):3158. doi: 10.1120/jacmp.v11i4.3158.
Varian has issued two Product Notification Letters warning of known inaccuracies in dwell positions for their GammaMed HDR ring applicator. This inaccuracy was measured for two sets of applicators. Autoexposed radiographs were taken of the HDR source at different dwell positions and analyzed per Varian recommendations using tools within the BrachyVision treatment planning program. Comparison between programmed and actual dwell positions showed the actual positions shifted distally by an average of 0.34 cm (0.17 cm-0.59 cm) across all positions in all rings. A correction method was developed and tested. During planning, the tip of the ring was extrapolated distally beyond its actual position in the patient image set and a proximal offset of the same distance was applied to the dwell positions. A global shift of 0.3 mm corrected all but the most proximal actual dwell position to within +2 mm of the planned position.
瓦里安公司发布了两份产品通知信，警告其 GammaMed HDR 环形施源器在驻留位置方面存在已知的不准确性。该不准确性是针对两组施源器进行测量的。对 HDR 源在不同驻留位置的自动曝光射线照片进行了拍摄，并按照瓦里安的建议使用 BrachyVision 治疗计划程序中的工具进行了分析。计划和实际驻留位置之间的比较表明，所有环的所有位置的实际位置平均向远端移动了 0.34 厘米（0.17 厘米-0.59 厘米）。开发并测试了一种校正方法。在计划阶段，将环形器的尖端在患者图像集中向远端外推超出其实际位置，并且将相同距离的近端偏移应用于驻留位置。整体移动 0.3 毫米可将除最接近近端的实际驻留位置之外的所有位置校正到计划位置的+2 毫米范围内。
