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A Dose Comparison Between CT and KUB Exams in a Kidney Stone Surveillance Program
J Shuman*, J Kuebker , Vanderbilt University, Nashville, TN
Presentations
SU-H2-GePD-I-4 (Sunday, July 30, 2017) 3:30 PM - 4:00 PM Room: Imaging ePoster Lounge
Purpose: To investigate the feasibility of using reduced-dose CT scans in a surveillance program for kidney stone forming patients. In phase one of this study, dose was compared between KUB exams and CT exams to determine which was higher. Dose as a function of patient size was also investigated.
Methods: In this IRB-approved retrospective study, patient data were gathered for 13 patients who had received both a KUB and a CT. The effective dose for the KUB exams was estimated using PCXMC, a Monte-Carlo based simulation program. Patient thickness was determined by measuring the AP thickness of the patient using CT data. The effective dose for the CT exams was estimated using the DLP reported by the scanner and applying the k factor given in AAPM Report 206.
Results: KUB exams deliver a much lower dose (16%) than standard CT. However, 61.5% of KUB exams were greater than 1.5 mSv and 15% were greater than 3 mSv, which are doses that can often be achieved with reduced dose CT techniques. All of the CT scans were greater than 3 mSv. In this study, there was one patient whose estimated dose from x-ray exams was greater than from CT. They underwent multiple high dose x-ray exams due to large body size; the CT was performed using a dual source CT scanner capable of creating diagnostic images at a lower dose.
Conclusion: While KUB x-ray dose was generally lower than CT for smaller patients, for a large patient the advantages of CT scanner dose reduction capabilities enabled this patient to receive a lower dose compared to the KUB study. Our preliminary data indicates that it may be possible for CT of large patients using state-of-the-art dose reduction methods to provide equivalent or lower dose surveillance scans than available with conventional x-ray imaging.
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