Assessment of lifetime attributable risk of stomach and colon cancer during abdominal CT examinations based on monte carlo simulation

Abstract

Abdominal CT examination is considered one of the most important diagnostic techniques to assess acute and chronic abdominal pain. Despite its beneficial, abdominal CT led to higher radiation dose to the patients compared to other techniques. Therefore, the purpose of this study was to evaluate the site-specific (stomach and colon) cancer risk of patients underwent abdominal CT examinations. The subject encompassed of 60 patients (34 males and 26 females, with a mean age of 38.5 ± 14.8) underwent CT abdomen examination on a calibrated CT scanner (Siemens Definition AS+) in Hospital Sultanah Aminah, Johor Bahru. The information regarding CT parameter and patient’s characteristics were collected. CT acquisition parameter such as tube voltage, tube current and dose information were recorded and analyzed by using CT-EXPO (Version 2.3.1, Germany). The mean values of CTDIvol, DLP, and effective dose were 13.9 mGy, 598.7 mGy cm and 9.5 mSv, respectively. The lifetime attributable risk (LAR) of colon and stomach cancer incidence was estimated based on the Biologic Effects of Ionizing Radiation VII (BEIR VII) report. The LAR of; stomach cancer were 2.3 and 1.0 per 100,000 populations; and colon cancer were 2.3 and 0.7 per 100,000 populations for male and female, respectively. The total LAR of stomach and colon cancer of 100,000 populations were 3.3 and 2.9, respectively. The cancer risk was substantially higher for male than for the female as influenced by the baseline incidence rate of cancer risk obtained from Malaysia Cancer Registry 2007 report. Hence, it is suggested that radiation protection principle such as justification and optimization should be taken into consideration before establishing imaging protocols for abdominal CT.