Establishment of Diagnostic Reference Levels in Patients with Renal Colic Using Non-contrast Computed Tomography: A Pilot Study

Non-contrast computed tomography (NCCT) is the standard examination for imaging and follow-up of patients with suspected kidney stones, as it is readily available and can be picked up more quickly. A diagnostic reference level (DRL) refers to a level of determinations that is employed in the process of optimizing medical exposure through the utilization of ionizing radiation. The purpose of this research was to determine the Urology and Nephrology Center institutional DRL for NCCT examinations in the assessment of renal colic stones by summarizing radiation doses collected for the computed tomography (CT) scanners systems at our institution, as well as measuring the CT effective dose from NCCT examinations. For all patient’s age, sex, height, weight, body mass index (BMI) and scan parameters were recorded from a picture archiving and communication system (PACS). Dose indicators such as volume computed tomography dose index (CTDIvol) and dose length product (DLP) for each examination were recorded from the three CT scanners at the Urology and Nephrology Center Mansoura University, Mansoura, Egypt. Data were obtained from 260 patients over 12 weeks. The Dose Reference Levels (DRLs) were established as the third quarter of the frequency the median values’ distribution CTDIvol and DLP, whereby the effective dose was subsequently computed. The manipulation and interpretation of the data were executed using SPSS (One-way ANOVA) findings demonstrate that there are significant differences between CTDIvol and DLP, among the studied three scanners at the center. We found that patients’ weight, age, and BMI ranges were 14.28(50–90) kg, 10.63(18–83) years, and 4.72(18.29–40) kg/m2, respectively. KVp and mAs range for the three investigated protocols were 110–120 and 37–31, respectively. The mean and the ranges of CTDIvol and DLP for patients were determined to be 6.73(with a range 3.47–12.2), 6.73(with a range of 3.47–15), 13.55(with a range of 4.3–23.24) mGy, and 341.08(with a range of 159–632), 335.56(with a range of 165.7–748.2), 706.49(with a range of 223.9–1200.81) mGy.cm, respectively. The values of mGy.cm were significantly different (p = 0.000) for the three CT scanners. The average effective dosages of the patients for each CT scanner were estimated to be 5.1, 5, 10.6 mSv, respectively. The DRL for the CTDIvol was 8.03, 7.93, 15.97mGy and for the DLP 391.75, 413.63, 829.31 mGy.cm, respectively. It concluded that there is a distinction that is statistically significant between the average effective doses of the three CT scanners. However, there aren’t any important differences between our established institutional DRLs and the standard DRLs for NCCT scans while assessing renal stones.