EVALUATION OF LINEAR ACCELERATOR GATING WITH REAL-TIME ELECTROMAGNETIC TRACKING
EVALUATION OF LINEAR ACCELERATOR GATING WITH REAL-TIME ELECTROMAGNETIC TRACKING
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DOI：
10.1016/j.ijrobp.2009.01.034
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发表时间：
2009-07-01
影响因子：
7
通讯作者：
Parikh, Parag
中科院分区：
文献类型：
--
作者：
Smith, Ryan L.;Lechleiter, Kristen;Parikh, Parag
目的：分次内器官运动会产生放射治疗剂量学误差。通常，使用通过外部传感器获得的实时呼吸相位来门控线性加速器。然而，外部解剖结构并不总是与内部位置良好相关。我们研究了一个波束门控技术，使用植入的无线转发器，提供实时反馈的肿瘤位置没有成像剂量的patient.Methods和Materials：Calypso医疗的四维电磁跟踪系统和瓦里安Trilogy直线加速器之间的接口。将胶片体模安装在用肺运动轨迹编程的运动平台上。当波束根据来自无线应答器的信号被选通时，进行了验证。束门控和系统laveliment的剂量学优势进行了quantitatived.Results：束门控使用内部位置监测提供了高达两倍的剂量梯度增加。对于门控，未在计划剂量+/-10 cGy范围内（最大剂量，类似于200 cGy）的点的百分比为3.4%，而在存在运动的情况下无干预的点的百分比为32.1%。应答器位置和直线加速器调制之间的平均延迟为75.0 +/- 12.7 ms的光束和65.1 +/- 12.9 ms的光束off.Conclusion：我们已经提出了一种新的方法门控直线加速器使用可跟踪的无线内部基准标记，而不使用电离辐射成像的结果。所观察到的lavelet适合于使用电磁基准标记进行门控，这导致在存在运动的情况下辐照的剂量测定改进。(C)2009爱思唯尔公司
Purpose: Intrafraction organ motion can produce dosimetric errors in radiotherapy. Commonly, the linear accelerator is gated using real-time breathing phase obtained by way of external sensors. However, the external anatomy does not always correlate well with the internal position. We examined a beam gating technique using signals from implanted wireless transponders that provided real-time feedback on the tumor location without an imaging dose to the patient.Methods and Materials: An interface was developed between Calypso Medical's four-dimensional electromagnetic tracking system and a Varian Trilogy linear accelerator. A film phantom was mounted on a motion platform programmed with lung motion trajectories. Deliveries were performed when the beam was gated according to the signal from the wireless transponders. The dosimetric advantages of beam gating and the system latencies were quantified.Results: Beam gating using on internal position monitoring provided up to a twofold increase in the dose gradients. The percentage of points failing to be within +/-10 cGy of the planned dose (maximal dose, similar to 200 cGy) was 3.4% for gating and 32.1% for no intervention in the presence of motion. The mean latencies between the transponder position and linear accelerator modulation were 75.0 +/- 12.7 ms for beam on and 65.1 +/- 12.9 ms for beam off.Conclusion: We have presented the results from a novel method for gating the linear accelerator using trackable wireless internal fiducial markers without the use of ionizing radiation for imaging. The latencies observed were suitable for gating using electromagnetic fiducial markers, which results in dosimetric improvements for irradiation in the presence of motion. (C) 2009 Elsevier Inc.