Fig. 1.

Illustrative procedures to develop the 3-dimensional brain phantom. a Tomographic images including the cortical grey matter, deep grey matter, white matter, cerebral spinal fluid space, skull, scalp and trachea regions that were generated at 3.6-mm intervals from anatomical MR images of a young healthy volunteer. Data were manually modified to fit to a head model. b Three-dimensional data were then generated using the computer-aided-design software, and modifications were made to guarantee the connectivity of both the grey matter and bone compartments. Careful attention was made to establish a liquid flow stream within the structure so that air bubbles could be easily removed from the liquid space. c A laser-modelling technique with a stereo-lithographic machine and a photo-curable material was employed to construct the 3-dimensional phantom. There was special attention to avoid contamination from the resin-based supporting material inside the grey matter and skull compartments, and also to make the inner wall surface of the phantom as smooth as possible. The speed and pitch of the machine as well as the temperature and humidity were optimized