Development of an acquisition and processing system for scintigraphic images obtained at different energies: advantages in research using several radioelements simultaneously

A scintigraphic system was developed. It includes a delay-line camera with a very wide analogue energy window and online mini-computer. The main feature of this system is that the coordinates X, Y (position) and Z (energy) of all photons detected in such a window are recorded sequentially. This gives the possibility of creating 'multichannel images', i.e. a set of two-dimensional matrices obtained simultaneously at several energies. Such images are especially valuable for clinical studies using several radioelements at a time. In useful images obtained under such conditions the elimination of troublesome effects due to tissue-scattered photons is a basic problem. Various techniques may be proposed, in particular a method using digital filtering for the non-stationary resolution correction. These filters are derived from a thorough study of the response of the system as a function of position, energy and depth of the scattering medium. Encouraging results were obtained in a number of studies on phantoms and clinical cases