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.

The purpose of this study was to evaluate the influence for image quality of diffusion weighted image (DWI) by gradient coil systems (two single gradient systems and a dual gradient system). We obtained DWIs of a phantom and three volunteer brains, changing gradient coil systems and echo time (TE) from configurable shortest TE to 130 ms. Image quality of DWI was evaluated by signal to noise ratio (SNR), image distortion, susceptibility artifact, and visual evaluation. SNR of dual gradient system and configurable shortest TE was the highest in phantom study, but there was no difference for SNR of volunteer brain images by each gradient coil system in visual evaluation. Image distortion of single gradient system with low gradient amplitude was the worst in phantom study, and the score of visual evaluation in susceptibility artifact was significantly lower than other gradient coil systems. Dual gradient system was low influence to image distortion and susceptibility artifact. In conclusion, using dual gradient system and configurable shortest TE is recommended for less distortion, low susceptibility artifact, and high SNR image.

The constancy test for quality control of X-ray image processing devices was evaluated using long-term and continuous constancy test results. Control was set so that under specific imaging conditions, variation in exposure dose is within 20% from the base line and variation in system sensitivity (S-value) obtained from images scanned with imaging plate is within 40%. Controlling the exposure dose enabled adjustments of tube currents and organized exchanges of the X-ray tube. Controlling the S-value allowed adjustments from increase due to age as well as organized exchanges of the photomultiplier tube foundation of the computed radiography scanner when control range is rapidly exceeded. Results from long-term and continuous constancy tests were of extreme value in comprehending the condition of the device for early detection of abnormalities, and thus indicate the significance of constancy tests for quality control of image processing device.