Radiation Dose Comparison between Intravenous Urography (IVU) and Unenhanced Helical Computed Tomography (UHCT) Urography

Intravenous urography (IVU) and unenhanced helical computed tomography (UHCT) urography are the two main procedures performed in the radiological investigation for urolithiasis (urinary stone). However, exposure to ionizing radiation is the main concern in both procedures. Therefore, a dose comparison study was conducted between IVU and UHCT urography procedures to determine the optimum exposure parameters in this study. An anthropomorphic whole body phantom was used following the exact procedure of UHCT urography and series of imaging for IVU with an administration of contrast media. Three different exposure parameters were used for IVU with 75 kVp, 80 kVp and 85 kVp while 100 kVp, 120 kVp and 140 kVp for UHCT urography respectively. As a result, the radiation doses for IVU were 1.40 mSv, 2.10 mSv and 2.79 mSv corresponding to 75 kVp, 80 kVp and 85 kVp. On the other hand, the radiation doses for UHCT urography were 0.76 mSv, 1.32 mSv and 1.82 mSv for 100 kVp, 120 kVp and 140 kVp, respectively. However the optimum image was obtained at 85 kVp for IVU and 120 kVp for UHCT urography. In conclusion, the doses obtained from IVU were consistently higher than UHCT urography but not signifi cantly different.