Detector identification through light separation for miniature imaging probe

Coronary artery disease (CAD) is the leading cause of death in most developed countries. A large portion of CAD is caused by rupture of unstable plaque, which is not detected by current diagnostic methods. By labeling the unstable plaque with beta emitting radioisotopes, it is possible to detect the plaques with a very narrow in situ detector system that is placed with a coronary angiography guidewire. Our current detection system uses fiber optics, with a single detector at the tip of each fiber, connected to a position-sensitive photomultiplier tube (PSPMT). The small diameter of the coronary artery limits our current system to six optical fibers. To increase the number of pixels, we are studying a multidetector concept for each fiber. By having multiple scintillating fibers coupled in series, with each scintillating fiber emitting a unique wavelength spectrum, the number of pixels can be doubled or tripled. The light is separated before reaching the PSPMT with a single diffraction grating. The PSPMT separates the detectors in one direction by fiber, and in the other direction by the spectral splitting of the different wavelengths of the scintillators.