Development of a subject-standing-type cone-beam computed tomography for chest and orthopedic imaging.
A subject-standing-type cone-beam computed tomography (CT) with high spatial resolution has been developed as a new three-dimensional imaging modality for subjects standing or sitting naturally on a turntable. A 16-in. X-ray image intensifier and charge coupled device camera acquires a 12-bit 5122-pixel projection at 60 f/s and the rotation period is 4.8 or 9.6 s for 288 or 576 projections, respectively. To reduce image noise, the system controls the X-ray pulse duration and iris-opening area through real-time analysis of the projection image. To improve CT accuracy and eliminate artifacts, the veiling glare of the image intensifier and scattered X-rays are corrected. Human chest and orthopedic studies with about 50 patients were conducted. Three-dimensional images with a spherical field of view with a diameter of 21-25 cm, 0.4- to 0.5-mm voxels and a 512(3) matrix were obtained. In coronal, sagittal and volume rendering images, the surface of arthrosis was visualized smoothly with a resolution higher than that of conventional CT. In the case of gonarthrosis, narrowing of the clearance at the surface of arthrosis was visualized clearly under body-weight burdening, which would be difficult if the subject was lying down.
Bab
R
R
Central Research Laboratory, Hitachi, Ltd, Kokubunji-shi, Tokyo, Japan. r-baba@crl.hitachi.co.jp
Ueda
K
K
Kuba
A
A
Kohda
E
E
Shiraga
N
N
Sanmiya
T
T
D000465:Algorithms; D001698:Biomedical Engineering; D004867:Equipment Design; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging; D019637:Orthopedic Procedures / Q000295:instrumentation / Q000706:statistics & numerical data; D019047:Phantoms, Imaging; D011030:Pneumothorax / Q000000981:diagnostic imaging; D011187:Posture; D013902:Radiography, Thoracic / Q000295:instrumentation / Q000706:statistics & numerical data; D012542:Scattering, Radiation; D014057:Tomography, X-Ray Computed / Q000295:instrumentation* / Q000706:statistics & numerical data