A New Head Holder for Reducing Axial Movement and Repositioning Errors during Physiological CT Imaging

Abstract

Objective 

We designed a new head holder for immobilization and repositioning in dynamic CT studies of the brain.

Materials and Methods 

A customized thermoplastic face mask and foam head rest were made to restrict movement of the head in all directions, but particularly out of the axial plane (z-movement).

Results 

This design provided a rigid, detailed mold of the face and back of the head that minimized motion during lengthy CT studies and enabled accurate repositioning of the head for follow-up studies. Markers applied directly to the skin were used to quantify z-movement.

Conclusion 

When tested on 12 subjects, immobilization was limited to <2.0 mm under worst-case conditions when the subject was asked to attempt forced movements. Repositioning was accurate to <1.5 mm when the subject was removed from the head holder and then placed back into it.