Ceramic radiation shield and radiation detector using same

Sintered ceramics (3) having such high radiation shielding capability and so easy to machine that they can be used as a radiation shield for radiation detectors are disclosed. The ceramics show a radiation shielding capability more than 90% and preferably have high light reflecting performance. They may comprises rare-earth oxides such as gadolinium oxide, oxide of at least one of vanadium, tantalum and niobium and alkaline-earth oxide which is used for a sintering agent. They can be used as a radiation shield in place of a molybdenum or tungsten radiation shielding plate and also as a light reflecting film (4) instead of titanium dioxide film in a radiation detector for radiation CT equipment.