The scintillation camera(Anger 1963) is a stationary device, which views all parts of the field of interest simultaneously. y-rays from the subject are collimated, and interact in a large flat disc of NaI (T1). The resulting scintillations are detected by an array of photo tubes situated on the opposite side of the crystal from the source. These phototubes are separated from the crystal by a light guide, in order that all tubes may view any scintillation. The total optical separation between the mean scintillation plane and the plane of the photocathodes of the detector phototubes constitutes an effective light guide thickness.

In order to investigate such a system analytically, it is necessary to determine the distribution of light in the plane of the photocathodes from a scintillation within the crystal. The relative responses of the photomultipliers may then be predicted, as a function of scintillation position, in terms of the light falling upon their photocathode.