  Scintillation detectors are widely used in modern physics, including various
medical tomographs. There are two types of position-sensitive scintillation
detectors: pixel arrays of "scintillator-photomultiplier" pairs and continuous
scintillator with multiple photomultipliers attached. For the last one, there
are two common ways to calculate the coordinates of the scintillation flash via
detector response in scintillation cameras: Anger's method and Monte-Carlo
simulation. In this article, we develop an analytical approach (so-called
"kaleidoscopic ray-tracing") to compute the energy outcome from several light
detectors in the scintillation camera with a continuous scintillator, which has
reflective and absorbing faces. We show that Anger's method is just an
approximation of the exact solution. Anger's method requires absorbing faces
only, so our approach covers a more general case. The derived method achieves
results, that are similar to the Monte-Carlo simulation, but it requires fewer
computations.
