A History of Compact MRI Systems in Tsukuba (1986–2018)

This paper reviews compact MRI systems developed at the University of Tsukuba between 1986 and 2018. The key technologies for the compact MRI systems are suitable portable MRI consoles and permanent magnets. For the portable consoles the central problem that had to be solved was the introduction of a pulse programmer using a digital signal processor board, and a digital synthesizer board both running under the Windows operating system. The electronics and software developed at the University of Tsukuba and the permanent magnets manufactured by Sumitomo Special Metals Company (SSMC, later NEOMAX engineering) enabled us to develop a variety of compact MRI systems for both clinical and non-clinical applications.