Radiography device with circuitry to correct for photodetector sensitivity

摘要

In an apparatus for examining a body by means of penetrating radiation a source is arranged to direct a swath of radiation through the body and a plurality of detectors are arranged to receive it thereafter. The source and detectors are arranged to orbit the body to obtain data for use in constructing a distribution of absorption of the radiation for part of the body. To correct for sensitivity variations in the detectors they are arranged to obtain data for radiation, not having passed through the body, from a further standard source at least twice in the orbital movement.