Magnetically inert medical projection system with an image-guiding optical fiber

A visual system for stimulating specific human brain functions inside a clinical magnetoencephalography (MEG) measurement chamber was developed. This system is based on a three-panel LCOS projection unit and uses a 4.5-m-long image-guiding optical-fiber bundle to transfer the image into the magnetically shielded MEG measurement chamber. In addition to a proper optical system design, special attention had to be paid to all materials used inside the magnetically shielded chamber. Here, no interfering fields due to electrics or ferromagnetic materials are allowed. The system concept, optical design, and the realized prototype are presented.