Clinical application of coincidence gamma camera for FDG imaging

The coincidence gamma camera imaging (CGI) which is now under development, is the method to image 18F-fluorodeoxyglucose (FDG) using an apparatus equipped SPECT with the same coincidence circuit as PET. In this paper, FDG imaging by CGI was evaluated and described of its present status. The capacity of CGI was compared with PET and FDG-SPECT for the ultra-high energy collimator method, and calculated the count per unit area from the actual radiation doses using the known amount of the surface source. The gamma camera was sensitive 10 fold more than of the collimator method. Authors performed the cardiac FDG imaging, the brain metabolic imaging and the tumor imaging by PET, SPECT, the collimator method and CGI, and compared with the properties of each method. Now in Japan in which the attenuation correction by the external source is not available, the brain metabolic imaging by CGI is the most stable FDG imaging, and to be clinically useful. On the other hand, cardiac and the tumor imagings have the problem on the absorption and have not been obtained the high quality images. In the future, when the attenuation correction is established, CGI will take the place of FDG-PET. (K.H.)