22 is shown with gamma cameras 14 and 16 at a variable angle all other elements are similar to the embodiment of fig2 the gamma ray detectors fpdxd and x ray tubes described are mounted to the gantry above fig4 shows yet another embodiment of the present invention the multimodality imaging system 24 is shown with a common gantry 26 a single gamma camera 28 and a single bar x ray detector 30 are both mounted on the gantry 26 x ray tube 32 is opposite bar x ray detector 30 the multimodality systems shown in the above embodiments are capable of many modes of operation the fpxpd is capable of performing simple planar x rays at a potentially high resolution if the fpdxd system is rotated about the patient axis it capable of performing a ct scan thus making it flat panel computerized tomography system or fpct system further such a system is capable of taking planner gamma camera images further such a system is capable of performing spect studies in isolation performing the above functions is well known to those skilled in the art however the various embodiments are capable of performing simultaneous spect fpct studies on a common gantry such studies not only yield the advantages of image fusion seen in conventional ct spect studies but also extend the fusion to the time domain and therefore realize the ct spect image fusion to the 4 th or temporal dimension performing a spect scan using gamma cameras involves acquiring data with the gamma camera advancing the camera by an angle of rotation acquiring another set of data repeated until enough data has been.