No abstract

The combination of ABM and radiation protection drape can reduce finger radiation exposure at assumed assist tool position. The space dose rate of the standing position of radiologists can get a clear dose of radiation reduction by the combination of both.

It is possible to obtain superior DIR images by using an optimization method that involves T1 mapping and a newly developed analysis algorithm.

Purpose: To estimate the annual effective dose per person in Gunma Prefecture by calculating average effective dose from computed tomography (CT) examinations in the area. Methods: We collected data on age, gender, anatomical region, and dose-length product (DLP) on patients who underwent CT examinations during a specific two-week period in July 2016 from 95 facilities in Gunma Prefecture. Result: We used data from 12,878 (7,014 males; 5,864 females) CT examinations on patients 10 years old and older (age 66.9+╱-17.5 years, 10-104 years). The effective doses were 2.4 mSv for head examinations (2,664 cases), 9.3 mSv for chest examinations (2,192 cases), 19.9 mSv for chest and abdomen examinations (3,906 cases), 16.5 mSv for abdomen examinations (1,611 cases), 14.5 mSv for coronary artery CT examinations (retrospective) (144 cases), 8.6 mSv for coronary artery CT examinations (prospective) (129 cases), 34.2 mSv for dynamic liver examinations (749 cases), with an average of 13.5 mSv overall. According to the National Database (from April, 2016 to March, 2017) of the Ministry of Health, Labour and Welfare, the annual number of CT examinations in Gunma prefecture was 430,000; thus the annual effective dose by CT examination per resident was calculated as 2.95 mSv. Conclusion: The effective dose per CT examination was 13.5 mSv. The annual effective dose per resident increased by about 28% from that of 2.3 mSv in 2000.

During the arterial phase acquisition of Gd-EOB-DTPA examinations, use of a small volume of the Gd-EOB-DTPA may make it difficult the encoding center of the k-space, and produce blurring. The previous studies revealed the encoding technique of the k-space was one of the most important reasons. However, there is no report to discuss the reasons with quantitative evaluations. The purpose of this study was to quantitatively evaluate the characteristics of the artifacts using different k-space encoding techniques (centric-view ordering (CVO) and sequential-view ordering (SVO)) for liver dynamic MRI in computer simulation study. This simulation study consists of the following steps. First of all, the creation of a time intensity curve, and original simulation images at certain points among the one phase dynamic scanning. Secondly, creation-simulated MR echo data from the created original images using FFT, and encoding simulated k-space using the simulated MR echo data. Finally, a reconstruction of simulated dynamic MR images from the simulated k-space, and to evaluate each simulated MR images, we measured modulation transfer functions (MTFs) from the bar patterns of the reconstructed images. The results of the CVO simulation indicated that the bar patterns were blurring compared to the images encoded by the SVO. The results of the SVO simulation indicated that the bar patterns were not enhanced at late scan timings. In addition, the results of MTFs indicated that there was no edge enhancement at all scan timings and both encoding techniques. In conclusion, it is possible to quantitatively evaluate the characteristics of artifacts using MTF, which was measured by the bar patterns, in liver dynamic MRI.