[Development of Automated Positioning System in General Radiography Examination-Application to Four Directions Cervical Spine Radiography].

To reduce a number of retaking with unnecessary radiation exposure, and to improve a quality of general radiography and efficiency of radiographic procedure, we propose an automated radiographic system that uses reference points on human face for determining exposure angle and beam center. As a preliminary study, we developed an automated positioning method for determining exposure angle and beam center of four directions (4R) cervical spine radiography by using the human body data from 3D reconstructed head-and-neck computed tomography (CT) images. An image for recognizing human-face was reconstructed and used for identifying the reference points. Clinical utility of this proposed method was demonstrated by using "KENZO" to inspect simulated projection X-ray images which were reconstructed from CT volume data. In this study, we reused a huge number of CT images, which were obtained in routine clinical procedure and had archived in medical institutions. This database, therefore, allowed us to develop a new radiological technique without any additional patient dose.