A new headholder for PET, CT, and NMR imaging.

A new headholder was developed for patient restraint and repositioning during positron emission tomography (PET), CT, and nuclear magnetic resonance (NMR) imaging procedures. A customized form was produced for each patient by pouring polyurethane resin and catalyst between an injection-molded polystyrene shell and a protective latex sheet and placing the patient's head in the form while the resin set. Excellent head restraint and repositioning was achieved when the headholder was used with a crossed-laser system. Repositioning accuracy was demonstrated by comparing transmission scans of the same patient obtained on different days and by comparing PET transmission scans with coplanar CT scans. No artifacts due to the headholder were apparent in CT, PET, and NMR images.