DEVELOPMENT OF A MINIATURE GAMMA-RAY ENDOSCOPIC PROBE FOR TUMOR-LOCALIZATION IN NUCLEAR-MEDICINE

We developed two types of miniature gamma-ray endoscopic probes to be inserted into a body cavity to detect invisibly small or deeply locate d tumors. One is a single detector system using a small BGO (Bi4Ge3O12 ) Crystal connected with a fiber optic light guide and the other is a dual detector system using a pair of single detector probes of the sam e size combined with a random coincidence technique. The performance o f these detectors was tested by using a point source and a hollow cyli ndrical water phantom that simulated a body cavity. Measured and calcu lated results indicated that a dual detector system can be used for re alistic tumor localization in a body cavity and a single detector syst em may be applied only for the detection of tumors in which radiopharm aceuticals that emit gamma rays of energy below about 200 keV are accu mulated.