title: Reducing radiation in CT urography for hematuria: Effect of using 100 kilovoltage protocol.
abstract: OBJECTIVE
  To compare 128-slice multidetector computed tomography (MDCT) at 100kVp and 120kVp for image quality and radiation dose.
  
  
  METHODS
  Our study had approval of our institutional review board. We retrospectively selected 25 patients who underwent CT urography for the evaluation of hematuria. The CT scans were taken with 128-slice MDCT, with three phases (precontrast, nephrographic, and excretory), using an automatic tube current modulation with reference tube level of 180mAs and tube voltages of either 100kVp (n=14, mean age 26.71) or 120kVp (n=11, mean age 25.54). The signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) of the urinary tract, the subjective image quality of the urinary tract evaluated with a five point scale by two radiologists and the effective dose calculated on the basis of dose-length-product (DLP) and volume-CT-dose-index (CTDIvol) were compared between the groups with Student's t test or Mann-Whitney U test.
  
  
  RESULTS
  There was no significant difference in the SNR (p=0.358), CNR (p=0.303) and the subjective image quality (p=0.486) between the two protocols. The mean CTDIvol, DLP and the effective dose in the 100kVp protocol were significantly lower than the 120kVp protocol (p=0.000, 0.000).
  
  
  CONCLUSIONS
  CT urography using 100kVp protocol resulted in reduction of radiation dose without loss of objective or subjective image quality.
authors.affiliation: Department of Radiology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, Republic of Korea. sungwonlee8@gmail.com
authors.forename: Sungwon
authors.initials: S
authors.lastname: Lee
authors.forename: Seung Eun
authors.initials: SE
authors.lastname: Jung
authors.forename: Sung Eun
authors.initials: SE
authors.lastname: Rha
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Byun
mesh_terms: D000328:Adult; D001822:Body Burden; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006417:Hematuria / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D011835:Radiation Protection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000379:methods*; D014567:Urography / Q000379:methods*; D055815:Young Adult