A novel imaging scheme for optical cameras used in a quality assurance detector for discrete spot scanning proton beam systems
A novel imaging scheme for optical cameras used in a quality assurance detector for discrete spot scanning proton beam systems
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DOI：
10.1016/j.nima.2019.05.038
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发表时间：
2019-09-21
影响因子：
1.4
通讯作者：
Beddar, Sam
中科院分区：
文献类型：
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作者：
Alsanea, Fahed;Darne, Chinmay;Beddar, Sam
包括相机和闪烁体体积的质量保证检测器由于其动态递送而对于在点扫描质子治疗中使用是令人感兴趣的。在这项工作中，我们的目标是通过使用创新的相机触发解决方案，以更大的灵活性比以前的系统所提供的扫描质子束的图像。主要目的是同步图像采集与质子束输送。使用由3个科学互补金属氧化物半导体相机和体积液体闪烁体（20 x 20 x 20 cm）组成的3D检测器。我们识别了同步加速器光束传输系统的相关信号来触发摄像机。这些信号使用开放式硬件微控制器进行处理，并使用示波器进行监测。我们通过比较5种能量（161.6、140.9、124.0、100.9和85.6 MeV）下触发与非触发图像采集的平均信号强度和标准差（每种能量50个点），对相机触发方案进行了评估。通过测试在9个不同位置（2个光斑/位置）输送的5种能量的图像强度变化性，进一步研究了触发方案的性能。我们还测量了不同曝光时间（1-1000毫秒）的背景信号，使用触发和非触发方案。对于低SNR（类似于20 dB），触发和非触发方案之间的平均信号强度差为10% +/-0.4%。图像强度变异性在2%以内。从最短曝光时间（1 ms）到最长曝光时间（1 s），背景信号强度变化仅为0.6%。我们展示了一个灵活的触发方案，使用一个开放的硬件微控制器与相机和闪烁体探测器系统的点扫描质子束，这将使有效的机器质量保证和治疗计划验证测量在未来。
Quality assurance detectors comprising cameras and a scintillator volume are of interest for use in spot scanning proton therapy due to its dynamic delivery. In this work, we aimed to image scanned proton beams with greater flexibility than is provided by previous systems by using an innovative camera triggering solution. The main objective was to synchronize image acquisitions with proton beam deliveries. A 3D detector composed of 3 scientific complementary metal-oxide-semiconductor cameras and a volumetric liquid scintillator (20 x20x 20 cm) were used. We identified relevant signals from the synchrotron beam delivery system to trigger the cameras. These signals were processed using an open hardware microcontroller and monitored using an oscilloscope. We evaluated the camera triggering scheme by comparing the mean signal intensity and standard deviations for triggered versus non-triggered image acquisitions at 5 energies (161.6, 140.9, 124.0, 100.9, and 85.6 MeV) with 50 spots per energy. The performance of the triggering scheme was further investigated by testing the image intensity variability for 5 energies delivered at 9 different location (2 spots/location). We also measured the background signals for different exposure times (1-1000 ms) using both triggered and non-triggered schemes. The mean signal intensity difference between triggered and non-triggered schemes was 10% +/- 0.4% for low SNR (similar to 20 dB). The image intensity variability was within 2%. The background signal intensity varied by only 0.6% from the shortest exposure time (1 ms) to the longest (1 s). We demonstrated a flexible triggering scheme using an open hardware microcontroller with a camera and scintillator detector system for a spot scanning proton beam, which will enable efficient machine quality assurance and treatment plan verification measurements in the future.