A system for nonradiographic source localization and real-time planning of intraoperative high dose rate brachytherapy.
A system for nonradiographic source localization and real-time planning of intraoperative high dose rate brachytherapy.
复制标题
一种用于术中高剂量率近距离放射治疗的非放射源定位和实时规划的系统。
DOI：
10.1118/1.598115
复制
发表时间：
1997
期刊：
影响因子：
3.8
通讯作者：
Anderson,LL
中科院分区：
文献类型：
--
作者：
Watanabe,Y;Anderson,LL
We have developed a system for source localization and real‐time planning of interstitial volume implants for intraoperative radiation therapy (IORT) using high dose rate remote afterloading techniques. Source localization is realized by using an electromagnetic tracking device, which consists of a transmitter coil, a receiver coil, and a signal processing unit, to generate the coordinates and orientation of the receiver. A drawback of the device is its sensitivity to adjacent metallic objects. Localization accuracy was evaluated in an operating room environment, where the metallic objects closest to the receiver are surgical retractors (that, incidentally, preclude radiographic localization). For achievable separation distances, we found an rms error of 0.7 mm in determining the distance between points 2 cm apart, thereby demonstrating the feasibility of the method. The receiver is mounted on a plastic block from which projects a long stylet and the transmitter is located at about 50 cm from the receiver. The stylet is inserted sequentially into source catheters to obtain the location and orientation data that serve as input to treatment planning software. The planning program optimizes source dwell time to make calculated dose conform to the dose prescribed on an ellipsoidal surface to an extent consistent with a certain level of dose uniformity inside the target volume. A least squares method is used that involves minimizing the objective function by a matrix method (nonnegative least squares). We have demonstrated that dwell time optimization can be performed in a short time and that the approach is adequate for the IORT application.
