Verification of proton range, position, and intensity in IMPT with a 3D liquid scintillator detector system
Verification of proton range, position, and intensity in IMPT with a 3D liquid scintillator detector system
复制标题
DOI：
10.1118/1.3681948
复制
发表时间：
2012-03-01
期刊：
影响因子：
3.8
通讯作者：
Beddar, S.
中科院分区：
文献类型：
--
作者：
Archambault, L.;Poenisch, F.;Beddar, S.
目的：使用点扫描质子束的强度调制质子治疗（IMPT）依赖于大量子束的递送来以高度共形的方式形成剂量分布。作者已经开发了一个3D系统的基础上液体闪烁体测量的空间位置，强度和渗透深度（能量）的质子beamlet in near real-time.Methods：该探测器系统由一个20 × 20 × 20 cc的液体闪烁体（LS）材料在一个不透光的外壳连接到一个CCD相机。该照相机具有25.7 × 19.3 cm的视场和0.4 mm的像素尺寸。当照射LS时，照相机连续获取LS内部产生的光分布的图像。辐照是用点扫描喷嘴产生的质子笔形束进行的。扫描水中标称范围为9.5 - 17.6 cm的双光束，以照射LS体模表面上10 x 10 cm见方的区域。结果：典型布拉格峰的信噪比约为170。从LS中产生的光分布测量的质子范围平均精确到0.3 mm以内。标称和测量范围之间的最大偏差为0.6 mm。测量的笔形射束的横向位置平均精确到0.4 mm以内。标称和测量的横向位置之间的最大偏差为0.8 mm;然而，可以通过校正光散射伪影来提高该测量的准确度。测量单个质子点的强度，精度范围从最小点强度（0.005 MU）的3%到最大点强度（0.04 MU）的0.5%。结论：我们的LS探测器系统已被证明能够快速，亚毫米空间定位在3D体积中递送的质子点。该系统可用于IMPT中光束的距离、强度和位置的检定。(C)2012年美国医学物理学家协会。[DOI 10.1118/1.3681948]
Purpose: Intensity-modulated proton therapy (IMPT) using spot scanned proton beams relies on the delivery of a large number of beamlets to shape the dose distribution in a highly conformal manner. The authors have developed a 3D system based on liquid scintillator to measure the spatial location, intensity, and depth of penetration (energy) of the proton beamlets in near real-time.Methods: The detector system consists of a 20 x 20 x 20 cc liquid scintillator (LS) material in a light tight enclosure connected to a CCD camera. This camera has a field of view of 25.7 by 19.3 cm and a pixel size of 0.4 mm. While the LS is irradiated, the camera continuously acquires images of the light distribution produced inside the LS. Irradiations were made with proton pencil beams produced with a spot-scanning nozzle. Pencil beams with nominal ranges in water between 9.5 and 17.6 cm were scanned to irradiate an area of 10 x 10 cm square on the surface of the LS phantom. Image frames were acquired at 50 ms per frame.Results: The signal to noise ratio of a typical Bragg peak was about 170. Proton range measured from the light distribution produced in the LS was accurate to within 0.3 mm on average. The largest deviation seen between the nominal and measured range was 0.6 mm. Lateral position of the measured pencil beam was accurate to within 0.4 mm on average. The largest deviation seen between the nominal and measured lateral position was 0.8 mm; however, the accuracy of this measurement could be improved by correcting light scattering artifacts. Intensity of single proton spots were measured with precision ranging from 3 % for the smallest spot intensity (0.005 MU) to 0.5 % for the largest spot (0.04 MU).Conclusions: Our LS detector system has been shown to be capable of fast, submillimeter spatial localization of proton spots delivered in a 3D volume. This system could be used for beam range, intensity and position verification in IMPT. (C) 2012 American Association of Physicists in Medicine. [DOI: 10.1118/1.3681948]