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With the increasing use of computed tomography (CT) for urography examinations, the indications for ‘conventional’ projection urography have changed and are more focused on high-contrast details. The purpose of the present study was to optimise the beam quality for urography examinations performed with a Gd2O2S:Tb flat-panel detector for the new conditions. Images of an anthropomorphic phantom were collected at different tube voltages with a CXDI-40G detector (Canon Inc., Tokyo, Japan). The images were analysed by radiologists and residents in a visual grading characteristics (VGCs) study. The tube voltage resulting in the best image quality was 55 kV, which therefore was selected for a clinical study. Images from 62 patients exposed with either 55 or 73 kV (original tube voltage) at constant effective doses were included. The 55-kV images underwent simulated dose reduction to represent images collected at 80, 64, 50, 40 and 32 % of the original dose level. All images were included in a VGC study where the observers rated the visibility of important anatomical landmarks. For images collected at 55 kV, an effective dose of ∼85 % resulted in the same image quality as for images collected at 73 kV at 100 % dose. In conclusion, a low tube voltage should be used for conventional urography focused on high-contrast details. The study indicates that using a tube voltage of 55 kV instead of 73 kV for a Gd2O2S:Tb flat-panel detector, the effective dose can be reduced by ∼10–20 % for normal-sized patients while maintaining image quality. [ABSTRACT FROM PUBLISHER]

BACKGROUND: Data on the efficacy and safety of screening for prostate cancer with magnetic resonance imaging (MIU) are needed from studies of follow-up screening. METHODS: In a population-based trial that started in 2015, we invited men who were 50 to years of age to undergo prostate-specific antigen (PSA) screening. Men with a PSA level of 3 ng per milliliter or higher underwent MRI of the prostate. Men were randomly assigned to the systematic biopsy group, in which they underwent systematic biopsy and, if suspicious lesions were found on MRI, targeted biopsy, or the MRI-Patholotargeted biopsy group, in which they underwent MRI-targeted biopsy only. At each visit, men were invited for repeat screening 2,4, or 8 years later, depending on the PSA level. The primary outcome was detection of clinically insignificant (International Society of Urological Pathology [ISUP] grade 1) prostate cancer; detection Inof clinically significant (ISUP grade 22) cancer was a secondary outcome, and detec. Univertion of clinically advanced or high-risk (metastatic or ISUP grade 4 or 5) cancer was also assessed. RESULTS: After a median follow-up of 3.9 years (approximately 26,000 person-years in each group), prostate cancer had been detected in 185 of the 6575 men (2.8°6) in the MRI-targeted biopsy group and 298 of the 6578 men (4.596) in the systematic biopsy group. The relative risk of detecting clinically insignificant cancer in the MRI-targeted biopsy group as compared with the systematic biopsy group was 0.43 (95% confidence interval ICI], 0.32 to 0.57; P<0.001) and was lower at repeat rounds screening than in the first round (relative risk, 0.25 vs. 0.49); the relative risk of diagnosis of clinically significant prostate cancer was 0.84 (95% CI, 0.66 to 1.07). The number of advanced or high-risk cancers detected (by screening or as interval cancer) was 15 in the MRI-targeted biopsy group and 23 in the systematic biopsy group (relative risk, 0.65; 95% CI, 0.34 to 1.24). Five severe adverse events occurred (three in the systematic biopsy group and two in the MIU-targeted biopsy group). CONCLUSIONS: In this trial, omitting biopsy in patients with negative MRI results eliminated more than half of diagnoses of clinically insignificant prostate cancer, and the associated risk of having incurable cancer diagnosed at screening or as interval cancer was very low. [ABSTRACT FROM AUTHOR]