Kezerashvili M, Rudin S, Bednarek D
University of Buffalo, Department of Radiology and Biophysical Sciences, NY 14215, USA.
Health Phys. 1997 Jan;72(1):141-6. doi: 10.1097/00004032-199701000-00020.
In Region of Interest (ROI) Fluoroscopy, an ROI filter is inserted into the x-ray beam in order to decrease the patient exposure in the peripheral part of the field of view. A filter placement device has been designed and constructed for the practical implementation of ROI fluoroscopy. When unmodified spot films are required during fluoroscopic procedures, an electronic signal from the high voltage generator triggers the filter placement device to remove the ROI filter automatically from the field of view and to reinsert it after the conclusion of the spot film exposure. The filter placement device is easily fastened to existing tracks on undertable tube fluoroscopic collimators. A transmission ionization chamber may be placed above the filter assembly so that radiation to the patient may be monitored during ROI fluoroscopic procedures. The mechanical design is compact and involves only one miniature gear-head motor. The filter placement device allows rapid filter positioning in 200 ms so that there is no interference with spot filming. A simple electronic circuit provides 8 volts for rapid motion of the filter support arm and 4 volts for holding the filter in place. This device demonstrates that ROI fluoroscopy with its associated large reduction in patient integral dose can be practically implemented in standard fluoroscopic equipment.
在感兴趣区域（ROI）荧光透视中，将一个ROI滤光片插入X射线束中，以减少视野周边部位的患者辐射剂量。已设计并制造了一种滤光片放置装置，用于ROI荧光透视的实际应用。在荧光透视过程中，如果需要未修改的点片，来自高压发生器的电子信号会触发滤光片放置装置，自动将ROI滤光片从视野中移除，并在点片曝光结束后重新插入。滤光片放置装置可轻松固定在床下管荧光透视准直器的现有轨道上。可在滤光片组件上方放置一个透射电离室，以便在ROI荧光透视过程中监测对患者的辐射。其机械设计紧凑，仅涉及一个微型齿轮头电机。滤光片放置装置可在200毫秒内快速定位滤光片，因此不会干扰点片拍摄。一个简单的电子电路为滤光片支撑臂的快速移动提供8伏电压，为将滤光片固定到位提供4伏电压。该装置表明，ROI荧光透视及其相关的患者累积剂量大幅降低能够在标准荧光透视设备中实际实现。
