| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1996: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1995: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Occlusive disease of the coronary artery, which can result in a fatal heart attack, is common in industrialized countries. Understanding of the stage of the development of the vessel occlusion as well as its location is essential for early recognition and management of the patients. A new method for clinical diagnosis of such occlusive disease is an application of synchrotron radiation combined with iodine K-edge subtraction angiography using an intravenous injection of a contrast medium In this method two X-ray images are taken at slightly (-400eV) below and above the energy of iodine K-absorption edge (33keV). After logarithmic subtraction of the two images all the background due to nonvascular body structures are eliminated, and an enhanced vascular image is obtained. Studies are being carried on at several synchrotron facilities in the world including photon Factory in Tsukuba, Japan.
The purpose of this study it to develop a Monte Carlo code to calculate patient absorbed dose during subtraction angiography using synchrotron radiation. There exist several transport codes for electrons and photons, among which EGS is most commonly and widely used in various fields. EGS is written in Mortran, a language especially developed for the code, and the users who are not familiar to the language are required to translate the code into FORTRAN.Further, the energy range that EGS can handle is very broad, from a few keV to several TeV,which makes the code rather too large for diagnostic X-ray applications. Therefore, a small code has been developed applicable specifically for these applications.
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