Rendering with Manifold Hopping

In a computerized tomographic apparatus for radiographic apparatus it has been proposed to orbit a source of X-radiation through several revolutions of the body of the patient. It is desirable to provide cooling to remove generated heat from the X-ray source, this being usually achieved by a cooling fluid such as oil. It is now proposed to provide a closed circuit cooling arrangement, for the source, comprising a circulatory oil path mounted to share in the orbit of the source without external fluid connections. To assist in cooling, the circuit is provided with a radiator and arranged such that, during pauses in the orbit, the radiator is brought to rest in a forced draught from a non-orbiting cooling fan.