Automated source tracking with a pinhole imaging system during high-dose-rate brachytherapy treatment
Automated source tracking with a pinhole imaging system during high-dose-rate brachytherapy treatment
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DOI：
10.1088/1361-6560/aacdc9
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发表时间：
2018-07-01
影响因子：
3.5
通讯作者：
Gomi, Tsutomu
中科院分区：
文献类型：
--
作者：
Watanabe, Yusuke;Muraishi, Hiroshi;Gomi, Tsutomu
高剂量率近距离放射治疗中，密封源的输送精度直接影响治疗效果。我们已经开发了一种针孔成像系统，用于在HDR近距离治疗过程中跟踪Ir-192辐射源。我们的系统包括一个双针孔准直器，闪烁体，和电荷耦合器件（CCD）相机。我们使用具有1.0 mm直径针孔的双针孔准直器获取立体位移图像来推断三维源位置。CCD照相机每2秒捕获闪烁光的连续图像，其对应于源位置。该系统利用模板匹配技术自动跟踪闪烁光点，并由此测量源位置。通过整合一系列的CCD图像，我们可以推断源驻留时间从像素值在整合images.We调查我们的系统在监测模拟近距离放射治疗的跟踪精度，因为它将执行宫颈癌，使用水作为人体组织的替身。Ir-192颗粒使用串联和卵形涂敷器移动通过水箱。CCD摄像机捕捉到水下Ir-192源在相当于普通临床情况的条件下产生的闪烁光的清晰图像。测量和参考的3D源的位置和停留时间之间的差异分别为1.5 +/- 0.7 mm和0.8 +/- 0.4 s，分别。该系统有可能跟踪体内的Ir-192源在真实的时间，并可能证明是一个有用的工具，在临床设置的HDR近距离放射治疗的质量保证。
The transportation accuracy of sealed radioisotope sources influences the therapeutic effect of high-dose-rate (HDR) brachytherapy. We have developed a pinhole imaging system for tracking an Ir-192 radiation source during HDR brachytherapy treatment. Our system consists of a dual- pinhole collimator, a scintillator, and a charge-coupled device (CCD) camera. We acquired stereo- shifted images to infer the source position in three dimensions using a dual pinhole collimator with 1.0 mm diameter pinholes. The CCD camera captured consecutive images of scintillation light that corresponds to the source positions every 2 s. The system automatically tracks scintillation light points using template-matching technique and measured the source positions therefrom. By integrating a series of CCD images, we could infer the source dwell time from the pixel values in the integrated image.We investigated the tracking accuracy of our system in monitoring simulated brachytherapy as it would be performed for cervical cancer by using water as a stand-in for human tissue. Ir-192 pellet was moved through a water tank using tandem and ovoid applicators. The CCD camera captured clear images of the scintillation light produced by the underwater Ir-192 source in conditions equivalent to common clinical situations. The differences between the measured and the reference 3D source positions and dwell times were 1.5 +/- 0.7 mm and 0.8 +/- 0.4 s, respectively.This system has the potential to track in vivo Ir-192 source in real time and may prove a useful tool for quality assurance during HDR brachytherapy treatments in clinical settings.