Respiratory gated irradiation system for heavy-ion radiotherapy
Respiratory gated irradiation system for heavy-ion radiotherapy
复制标题
DOI：
10.1016/s0360-3016(00)00524-1
复制
发表时间：
2000-07-01
影响因子：
7
通讯作者：
Kanazawa, M
中科院分区：
文献类型：
--
作者：
Minohara, S;Kanai, T;Kanazawa, M
目的：为了减少因呼吸引起的运动靶的治疗余量，我们研制了一种用于重离子放疗的门控照射系统。方法与材料：通过胸壁周围体表的运动来检测患者因呼吸引起的运动，研制了一种利用红外光斑和位置敏感探测器的呼吸传感器。根据呼吸波形生成请求碳束的ri定时信号，并使用rf敲除方法从同步加速器中提取碳束。用于治疗计划的CT图像与呼吸运动同步拍摄。在患者定位时，采用数字化透视图像叠加呼吸波形，利用数字化透视视频图像检测呼吸传感器信号与器官运动之间的关系。结果：闭门时间设置在呼气末期，因为隔膜的运动比吸气期的运动更慢，更容易重复。闭门时间设置在呼气末期。呼吸传感器的信号显示胸壁上下位置之间的相位差为120毫秒。隔膜的运动被较低位置的呼吸波形延迟200毫秒。光束提取系统根据光束开/关逻辑进行门控，门控CT扫描仪性能良好。在门控照射下，沿运动轴的剂量谱的侧向半影大小明显减小。在40.0、29.0和13.0 mm行程下，非门控与门控侧落的比值分别为4.3、3.5和2.0。结论：建立了一套适用于重离子放射治疗的门控照射综合治疗体系。我们发现，在该系统下，尽管目标移动了两到三次，但沿体轴的目标余量可以减少到5-10 mm。截至1999年7月底，已有150多名肺癌或肝癌患者接受了这种门控照射系统的治疗。
Purpose: In order to reduce the treatment margin of the moving target due to breathing, we developed a gated irradiation system for heavy-ion radiotherapy.Methods and Materials: The motion of a patient due to respiration is detected by the motion of the body surface around the chest wall, A respiratory sensor was developed using an infrared light spot and a position-sensitive detector. ri timing signal to request a beam is generated in response to the respiration waveform, and a carbon beam is extracted from the synchrotron using a RF-knockout method. CT images for treatment planning are taken in synchronization with the respiratory motion. For patient positioning, digitized fluoroscopic images superimposed with the respiration waveform mere used, The relation between the respiratory sensor signal and the organ motion was examined using digitized video images from fluoroscopy. The performance of our gated system was demonstrated by using the moving phantom, and dose profiles were measured in the direction of phantom motion,Results: The timing of gate-on is set at the end of the expiratory phase, because the motion of the diaphragm is slower and more reproducible than during the inspiratory phase. The signal of the respiratory sensor shows a phase difference of 120 milliseconds between lower and upper locations on the chest wall. The motion of diaphragm is delayed by 200 milliseconds from the respiration waveform at the lower location. The beam extraction system worked according to the beam on/off logic for gating, and the gated CT scanner performed well. The lateral penumbra size of the dose profile along the moving axis was distinguishably decreased by the gated irradiation. The ratio of the nongated to gated lateral fall-off was 4.3, 3.5, and 2.0 under the stroke of 40.0, 29.0, and 13.0 mm respectively.Conclusion: We developed a total treatment system of gated irradiation for heavy-ion radiotherapy. We found that vith this system the target margin along the body axis could be decreased to 5-10 mm although the target moved twice or three times. Over 150 patients with lung or liver cancer had already been treated by this gated irradiation system by the end of July 1999, (C) 2000 Elsevier Science Inc.