[Availability and improvement of a vacuum-type immobilization device in pediatric CT]

The essential factors for an immobilization device in pediatric CT are 1) absence of artifacts, 2) safety, 3) no disturbance of the patient's sedation, and 4) ease of handling. We evaluated the suitability of a commercially available vacuum-type immobilization device designed for radiation therapy (Vac-Lok) that meets these requisites. There were no artifacts in scans of the water phantom. The device easily immobilized the patient, was quick to release, and was superior to previous immobilization systems, according to replies to a questionnaire administered to physicians, technologists, and nurses. Schedule delays were reduced by using this device to examine sedated patients (up to 1 year of age). Despite these advantages, the device was too small to immobilize both extremities together when examining older patients. In order to overcome this problem, we invented a special immobilization device for pediatric CT. The new device could be applied to taller patients, up to 85 cm in height(the average height of 2-year-old infants), and was able to contribute to efficient utilization of the examination room.