Prototype X-ray Detector of Real-time Monitoring System for Interventional Radiology Using Plastic Scintillators and Optical Fiber

Interventional radiology (IVR) is a medical subspecialty of radiology to realizeimage-guided surgical procedures using imaging modalities, such as X-ray fluoroscopy. Recently, IVR is increasingly used in treatment of vascular lesions due to its low invasiveness. On the other hand, skin injuries by prolonged X-ray exposure in duration of procedure have been reported(1). Therefore, monitoring and control of skin dose are desired in clinical sites for reduction of excessive X-ray exposure.There are several requirements for dose monitors in IVR. The dose monitors need to: 1) measure the position distribution of dose on skin surfaces; 2) be mounted on patients and directly able to detect incident X-rays to the skin surface since various angle projections of X-ray are needed in one operation of some IVR procedures; 3) be composed of radiolucent material in order to interfere with the IVR procedure; and 4) display the X-ray dose in real-time to control total dose in the IVR procedure. While various dosimeters have been proposed and clinically used, none can achieve all the requirements at the same time.Previously, Moritake et al. proposed a precise mapping system of skin dose using a number of radiophotoluminescence glass dosimeters(2). In the system, the 60 glass chips are in pockets placed on a polyester cap worn on a patient head. The system can obtain dose distribution precisely on the patient head after the IVR procedure. However radiophotoluminescence glass dosimeters cannot obtained patient skin dose in real-time.We propose a real-time dose distribution monitor for interventional radiology. Figure 1 shows a conceptual scheme of our proposed dose monitor. Scintillation detectors which consist of low stopping power materials, such as plastic scintillators, are placed on a stretchable cap which can be worn by the patient to achieve requirements 1 and 2. Scintillation light is fed to photo detectors outside the FOV through plastic fibers. This means that there are only radiolucent materials in the FOV and the proposed dose monitor does not interfere with the IVR procedure. The scintillation detector can easily display acquired data in real-time. Therefore the proposed dose monitor can achieve all four requirements. In this presentation, we construct a prototype X-ray detector element for the real-time dose distribution monitor and conduct a performance test with synchrotron radiation and a micro CT