Novel measuring method of urethane-foam mattress deformation using X-ray CT

Abstract

A novel method to measure the deformation of a urethane-foam object using an X-ray computed tomography (X-ray CT) technique was proposed and examined. The proposed method is made up of following two steps. First, X-ray sensitive ‘contrast media’ were drawn in lattice-like manner on top and bottom surfaces and internal planes of urethane-foam, which enabled visualization of the drawn positions in CT images. Second, position data of contrast media were then converted into the numerical values in a prescribed coordinate to measure the deformation. It was found that the contrast media successfully visualized outer and internal displacement with the urethane-foam deformation, and the comprehensive error of measurement was 0.3 mm in root mean square. As a trial for further practical purpose, the deformation of the urethane-foam mattress with a human-body model on it was measured using this method. A urethane-foam mattress with contrast media was prepared, a human trunk model was set on the mattress, and the mattress with the model was subjected to X-ray CT. The deformation state at surface of, and especially inside of, the mattress could be visualized and measured. We concluded that the proposed method could bring us an information on deformation state of the urethane-foam and the urethane-foam mattress as numerical values.