Development of a miniature gamma-ray endoscopic probe for tumor localization in nuclear medicine

Two types of miniature gamma-ray endoscopic probes developed for insertion into a body cavity to detect invisibly small or deeply located tumors are described. 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 same size combined with a random coincidence technique. The performance of these detectors was tested by using a point source and a hollow cylindrical water phantom that simulated a body cavity. Measured and calculated results indicated that a dual detector system can be used for realistic tumor localization in a body cavity, and a single detector system may be applied only for the detection of tumors in which radiopharmaceuticals that emit gamma rays of energy below about 200 keV are accumulated