Apparatus and methods for determining spatial coordinates of

Abstract

A system and method for diagnostic testing of structures within a body, e.g., organs within the body of a living being, which has been provided with a radioactive imaging agent, e.g., a radiotracer, to cause the structure to produce gamma rays, associated characteristic x rays, and a continuum of Compton-scattered photons. The system includes a radiation receiving device, e.g., a hand-held probe or camera, an associated signal processor, and an analyzer. The radiation receiving device is arranged to be located adjacent the body and the structure for receiving gamma rays and characteristic x rays emitted from the structure and for providing a processed electrical signal representative thereof. The processed electrical signal includes a first portion representing the characteristic x rays received and a second portion representing the gamma rays received. In a preferred embodiment of the invention the signal processor removes the signal corresponding to the Compton-scattered photons from the electrical signal in the region of the full-energy gamma ray and the characteristic x ray. The analyzer is arranged to selectively use the x-ray portion of said processed signal to provide near-field information about the structure, to selectively use both the x-ray and the gamma-ray portions of said processed signal to provide near-field and far-field information about the structure, and to selectively use the gamma-ray portion of said processed signal to provide extended field information about the structure.