[Study on the effect of setting the region of interest for exposure index computing].

Exposure index (EI) is expected as important standard for the optimization of image quality and exposed dose in digital radiography. It is set a region of interest (ROI) in a radiograph, to obtain a histogram of pixel values within an ROI, it is computed as EI of the image representative value of the histogram. In this study, we examined the effects of setting the ROI for EI computing.

Optimization of dual-energy subtraction chest radiography by use of a direct-conversion flat-panel detector system.

We aimed to optimize the exposure conditions in the acquisition of soft-tissue images using dual-energy subtraction chest radiography with a direct-conversion flat-panel detector system. Two separate chest images were acquired at high- and low-energy exposures with standard or thick chest phantoms. The high-energy exposure was fixed at 120 kVp with the use of an auto-exposure control technique.

[Difference in the level of patient treatment safety analysed by the years of experience of the radiological technologists].

According to the report of the reporting project of medical accidents (from July 2010 to March 2011) which was issued by the Ministry of Health, Labour, and Welfare, a lot of incidents involving radiological technologists occurred among young ages or experienced ages; therefore, we focused on this matter. We carried out questionnaires for the radiological technologists at the radiology department of our hospital to see how concerned they are about the patient treatment safety. We examined the causal relationship between years of their experience and their concerns about the patient treatment safety.

[Relationship between the effect of medial rotation of the foot axis by ankle dorsiflexion and the ability to visualize the femoral neck axis in the hip joint anterio-posterior radiography: evaluation by magnetic resonance images].

In scanning of the hip joint anterio-posterior radiography, by changing the lower extremities to the extension position and moving the foot axis (base line of the foot) by medial rotation, the angle of anteversion of the femoral neck is corrected. In this study, we assessed the effects on medial rotation of the femoral neck when keeping the planta vertically-positioned by ankle dorsiflexion (intermediate position of the ankle) and making change of the medial rotation angle of the foot axis by scanning the magnetic resonance (MR) images of knee joints and hip joints. The subjects in this study were 12 males (age: 37.

[Study of appropriate dosing in consideration of image quality and patient dose on the digital radiography].

Recently about 90% of radiographs have been taken by the digital radiographic system in Japan, but the exposure dose of the patients are about ten-times different among the systems. We understood it by a surveytaken in 2007. We studied the visual evaluation with varying exposure doses using the image phantom of the lumber AP, lumber lateral and hip AP.

[Gravity sag view of lateral radiography of the knee].

The gravity sag view(GSV)is a lateral radiograph taken in the same position when the posterior sag sign is observed. The purpose of this study was to standardize the radiography technique for GSV by adjusting lateral rotation. To confirm the benchmark and correction angle(CA)for the GSV position, we assessed three-dimensional(3D)CT of the GSV position of the knee using normal volunteers.

[Usefulness of high energy radiation using copper filter on CR chest radiography].

The bone contrast on chest radiographs obtaind with computed radiography (CR, hereafter) is not decreased enough compaired with that for screen/film combination, even if we use a high tube voltage. This may be because the Exporsure Data Recognizer which can normalize the density and contrast of the chest images is performed. In order to increase the diagnostic accuracy for the lung disease,we propose to use a copper additional filter to decrease the bone contrast.