Contents lists available at ScienceDirect Radiation Physics and Chemistry journal homepage: www.elsevier.com/locate/radphyschem Estimation of radiation cancer risk in CT-KUB M.K.A. Karim a,b, ⁎ , S. Hashim a , K.A. Bakar c , D.A. Bradley d,e , W.C. Ang a , N.A. Bahrudin a , M.H.A. Mhareb f a Department of Physics, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia b Department of Radiology, National Cancer Institute, Presint 7, 62250 Putrajaya, Malaysia c Department of Radiology, Hospital Sultanah Aminah 80100 Johor Bahru, Johor, Malaysia d Centre for Nuclear & Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH, U.K. e Sunway University, Institute for Health Care Development, Jalan Universiti, 46150 Petaling Jaya, Malaysia f Radiation Protection Directorate, Energy and Minerals Regulatory Commission, 11183 Amman, Jordan ARTICLE INFO Keywords: CT-KUB Patient effective dose Organ equivalent dose and cancer risks ABSTRACT The increased demand for computed tomography (CT) in radiological scanning examinations raises the question of a potential health impact from the associated radiation exposures. Focusing on CT kidney-ureter-bladder (CT-KUB) procedures, this work was aimed at determining organ equivalent dose using a commercial CT dose calculator and providing an estimate of cancer risks. The study, which included 64 patients (32 males and 32 females, mean age 55.5 years and age range 30–80 years), involved use of a calibrated CT scanner (Siemens- Somatom Emotion 16-slice). The CT exposures parameter including tube potential, pitch factor, tube current, volume CT dose index (CTDI vol ) and dose-length product (DLP) were recorded and analyzed using CT-EXPO (Version 2.3.1, Germany). Patient organ doses, including for stomach, liver, colon, bladder, red bone marrow, prostate and ovaries were calculated and converted into cancer risks using age- and sex-specific data published in the Biological Effects of Ionizing Radiation (BEIR) VII report. With a median value scan range of 36.1 cm, the CTDI vol , DLP, and effective dose were found to be 10.7 mGy, 390.3 mGy cm and 6.2 mSv, respectively. The mean cancer risks for males and females were estimated to be respectively 25 and 46 out of 100,000 procedures with effective doses between 4.2 mSv and 10.1 mSv. Given the increased cancer risks from current CT-KUB procedures compared to conventional examinations, we propose that the low dose protocols for unenhanced CT procedures be taken into consideration before establishing imaging protocols for CT-KUB. 1. Introduction CT kidney-ureter-bladder (CT-KUB) scans are among the most common CT procedures used in investigations of the presence of renal and urethral calculi in the urinary tract system (Nadeem et al., 2012). CT-KUB procedures have largely replaced Intravenous Urography (IVU) procedures and also plain KUB x-ray studies, particularly in the diagnosis of macroscopic haematuria (O'Kane et al., 2016a; Patatas et al., 2012). Due to its sensitivity, short scan-times and three-fold diagnostic value compared to IVU, CT-KUB is considered to be the new gold-standard for the evaluation of renal disease (Nadeem et al., 2012), making it one of the most prescribed CT examinations (Siegel, 2005). The number of CT-KUB examinations has increased significantly, due in no small part to the availability of multi-slice CT (MSCT) scanners that provide for faster image acquisition and better image quality (Lee and Chhem, 2010; Patatas et al., 2012). It has been estimated that CT procedures make up 20% of all radiological examinations, accounting for in excess of 70% of the overall dose from all medical diagnostic radiation exposures (Rehani, 2012). In regard to CT-KUB, this procedure has been associated with effective doses as high as 10–15 mSv, depending upon the exposure parameters (Alzimami et al., 2013; McLaughlin et al., 2014). The dose information of each scan, typically available from data supplied at the CT console, is important in estimating radiation risks (Chen et al., 2012; Kalender, 2014). The detrimental effect and the risks will vary from case to case, dependency upon populations, age and sex of patients playing sig- nificant role. The 7th report on Biological Effects of Ionizing Radiation of the National Academy of Sciences (BEIR VII Phase 2) estimates risks for low-level ionizing radiation using the most recent data from studies of atomic bomb survivors (National Academy of Sciences, 2006 ). In accord with the absorbed doses received, the same report includes risk projections for each organ, the average effective dose being around 10 mSv (Brenner and Hall, 2007; Smith-Bindman et al., 2009). The most important dose information for estimating cancer risk http://dx.doi.org/10.1016/j.radphyschem.2016.10.024 Received 28 September 2015; Received in revised form 29 October 2016; Accepted 31 October 2016 ⁎ Corresponding author at: Department of Radiology, National Cancer Institute, Presint 7, 62250 Putrajaya, Malaysia. E-mail address: khalis.karim@gmail.com (M.K.A. Karim). Radiation Physics and Chemistry xx (xxxx) xxxx–xxxx 0969-806X/ © 2016 Elsevier Ltd. All rights reserved. Available online xxxx Please cite this article as: Karim, M.K., Radiation Physics and Chemistry (2016), http://dx.doi.org/10.1016/j.radphyschem.2016.10.024