A high resolution single photon tomographic system for head imaging, GAMMATOM-Ⅱ, was developed.
The system consists of 36-NaI(Tl) cylindrical crystals which are arranged in a circular form on the 4 banks, each bank with 9 crystals.
The ring artefacts which had appeared in our first system was removed by refining the electronics and mechanical systems. Using the new effective sampling scheme (totally two rotations and one shift motion), sampling of the one eighth of the detector width was successfully achieved.
The desired resolution of 7-mm FWHM was achieved with a resolution phantom (20-cm diameter) with 99mTc.
System design and improvements are reported with the performance characteristics of our system.