Do NOT use Multi-Detector CT Exams - compared to EBCT it is less well understood how to use the data it produces and it is a substantially more mrems than the EBCT (which is about 60 mrems).
Not to shock you but 99% of coronary CT's are not done on electron beam CT. The machines are to expensive. 64 or 128 slice Helical CT's give excellent images with albeit with a higher dose