Seated vs. supine: optimum measurement pose for brain-dedicated PET

For brain-dedicated PET (Positron Emission Tomography) scanners being developed recently, a seated position (sitting style) is considered as a measurement posture. The sitting style enables molecular imaging studies under conditions close to daily life, and it is expected that the brain PET scanners can be downsized. However, the effect on head-motion suppression in the seated position compared with the supine (face-up) position, which is generally employed in clinical PET studies, is not clear. In this study, therefore, we developed a marker less and contactless head motion tracking system, and we conducted a healthy volunteer study of head motion tracking in several positions to reveal the optimum scanning pose for brain PET. In detail, we used the Kinect (Microsoft) as a range sensor, and developed software that can measure the head motion with the accuracy of about 1 mm (translation) and less than 1 degree (rotation). In the healthy volunteer study using the system, we measured the head motion in face-up position, normal sitting style, and reclining-chair style. As a result, the normal sitting style had the largest head movement, and reclining-chair style had less movement than the face-up position. We concluded that the reclining-chair style has the same as or superior effect on head motion suppression than the face-up position.