High resolution gel-dosimetry by optical-CT and MR scanning
High resolution gel-dosimetry by optical-CT and MR scanning
复制标题
DOI：
10.1118/1.1380430
复制
发表时间：
2001-07-01
期刊：
影响因子：
3.8
通讯作者：
Jaffray, DA
中科院分区：
文献类型：
--
作者：
Oldham, M;Siewerdsen, JH;Jaffray, DA
强度调制放射治疗（IMRT）递送的复杂性增加，产生了对能够测量和验证复杂递送的高分辨率3D剂量测定（三维）系统的需要。目前的临床方法局限于单点（例如，离子室）或2D平面（例如，电影），并且是劳动密集型的。在本文中，我们表明，凝胶剂量测定结合光学CT扫描可以产生足够的准确度，分辨率和精度，以允许验证复杂的放射外科手术交付，并通过扩展IMRT交付的剂量图。放射外科剂量分布代表了外部射束治疗中遇到的最具挑战性的情况，因为剂量梯度很陡，输送分辨率很高。我们通过RTAP（分辨率-时间-准确度-精确度）标准来描述放射外科的严格要求，RTAP标准定义为小于或等于1 mm（3）空间分辨率，小于或等于1小时成像时间，精确度在3%以内，精确度在小于或等于1%以内。RTAP标准适用于内部激光为基础的光学CT扫描系统在这里，并使用含有BANG 3（TM）凝胶的凝胶瓶进行评价。随后使用凝胶制造商推荐的MR成像方案对相同的凝胶烧瓶进行成像，但进行修改以尽可能接近地匹配RTAP。由此产生的剂量图显示了高精度（
The increased intricacy of Intensity-Modulated-Radiation-Therapy (IMRT) delivery has created the need for a high-resolution 3D-dosimetry (three-dimensional) system capable of measuring and verifying the complex delivery. Present clinical methods are inadequate being restricted to single points (e.g., ion-chambers) or to 2D planes (e.g., film), and are labor intensive. In this paper we show that gel-dosimetry in conjunction with optical-CT scanning can yield maps of dose that are of sufficient accuracy, resolution and precision to allow verification of complex radiosurgery deliveries, and by extension IMRT deliveries. The radiosurgery dose-distribution represents the most challenging case encountered in external beam therapy by virtue of the steep dose-gradients and high resolution of delivery. We characterize the stringent radiosurgery requirements by the RTAP (Resolution-Time-Accuracy-Precision) criteria defined as less than or equal to1 mm(3) spatial resolution, less than or equal to1 hour imaging time, accurate to within 3%, and within less than or equal to1% precision. The RTAP criteria is applied to an in-house laser-based optical-CT scanning system presented here, and evaluated using gel-flasks containing BANG3(TM) gel. The same gel flasks were subsequently imaged using the MR imaging protocol recommended by the gel manufacturer, but modified to match as closely as possible the RTAP. The resulting dose-maps demonstrate the high precision (