Design of microcontroller based circuitry for use in the multi-tesla field strength environments found in functional Magnetic Resonance Imaging

As MRI (magnetic resonance imaging)-a harmless, efficient and noninvasive medical tissue imaging system-constitutes an ever increasing part of general practice medical diagnostics, there arises a need for diagnostic equipment which may coexist in the near field of their powerfully magnetic periphery. The design of such devices must begin with the elimination of all components containing ferrous materials-save the most austenitic of stainless steels-as any such component might well become a mortal projectile. Furthermore, as the field strengths of imagers' superconducting magnets increase to the 3 to 5 Tesla range such as those found in fMRI (functional magnetic resonance imaging)-a high speed and resolution form of MRI used for real-time (functional) analyses such as in brain protonation (activity) localization and in cardiac function imaging,- so increases the need to eliminate all ferromagnetic materials which would otherwise introduce unacceptable noise into the imagers' highly sensitive receivers. The approach contained herein chronicles the construction of a novel flexible visual stimulator consisting of a microcontroller driven array of 512 LEDs (light emitting diodes) used to stimulate optical vergence response in human test subjects whilst localizing correlated brain activity in the study of VI (vergence impaired) individuals such as those with TBIs (traumatic brain injuries).