J022032 ライブラリとしてボクセルモデルを利用した骨の三次元位置・姿勢推定([J02203]診療技術と臨床バイオメカニクス(3))

Abstract

Template pattern matching method that is one of the kinematic analyses of joints requires an accurate 3D model of a subject. This 3D model is used as a template. In order to make 3D model, CT is generally used. However, if the kinematic analysis can be carried out without CT, the analysis will be more convenient. In this study, the making method of 3D model from 2 X-ray projection images of the subject and a prepared 3D standard model of bone was proposed. 3D standard model was deformed from the 2 X-ray projection images of the subject. Since the 3D standard model consisted of voxels, the deformation can be performed easily. The standard model was created from CT data of a volunteer (male:22yo, 62kg, 173cm). The subject was 24 years old male, 68kg, and 178 cm. In results, the standard deviation of errors of femur were θx=0.95±0.45 deg and θy=090±0.35 deg. The standard deviation of errors of tibia, were Ox=1.40±0.35 deg and θy=0.75±0.35deg. As to the 3D deformation model, a part of shape between the 3D deformation model and subject's bone was different. Particularly in articular surfaces, these differences were observed. However, the accuracy in this study was satisfied with clinical accuracy. This result shows that, even if 3D accurate model of subject can not be required, 3D kinematic analysis can be performed.