Abstract: An apparatus for optically transmitting signals from a rotatable body to a stationary side or vice versa in a non-contact manner, includes a plurality of light emitting elements excited by a PCM signal from a signal source and a plurality of light receiving elements disposed in opposition with the light emitting elements for receiving light therefrom. A plurality of sets each including plural light receiving or emitting elements are provided at the stationary side in association with the respective light emitting or receiving elements disposed at the rotatable body side. Alternatively, a plurality of sets each including plural light emitting elements are provided at the rotatable body side in association with the respective light receiving elements disposed at the stationary side. The elements in such plural sets are selected in accordance with the rotation of the rotatable body.

Abstract: In a radiation detector including a radiation sensitive scintillator and a photo-electric conversion element, a film of silicon nitride providing a modified refractive index is interposed between the scintillator and the photo-electric conversion element.

Abstract: A scanner for positron emission computed tomography comprising a rotary member rotatable within the plane of a slice about an axis lying perpendicular to this plane and having means for accommodating a subject for examination, a drive means for rotating this rotary member within the plane of slice, and a plurality of radiation detectors provided on the rotary member so as to substantially face each other relative to the subject to be examined, in which the radiation detectors are disposed so that at least some of them are either positioned with irregular spacing relative to each other, or positioned at irregular distances from the axis of rotation.