Radiation dose associated with common computed tomography examination

Abstract

ObjectiveTo survey computed tomography (CT) radiation dose associated with non-contrast spiral Multislice CT examination in our institute. MethodsDetailed parameters for 362 consecutive examinations, including the patient weight, height, volume CT dose index (CTDIvol), scan length, and dose length product (DLP) were recorded from the dose report. Effectivedose(E) was estimated for each patient. The differences between E doses were statistically analyzed using SSPS. ResultsPatients body mass index (BMI) was 13.4 to 51.42 (average BMI 29.5kg/m). Patients dose data (1 scan phase for each patient) from dose information: the median value of DLP was 586.45mGycm (83.30–1179.70mGycm), median value of CTDIvol was 12.07 (2.20–23.9mGy), median value of mAs used was 186.50 (34–334mAs). Effective dose range was (1.1–16.5mSv) according to international commission of radiological protection (ICRP) 103 and according to ICRP60 the range was (1.3–18.93mSv). Median value of frequent CT examinations for the same patient was 2 (min 1 scan/year & max 11 scan/year). CT dose variation was highly significant (p value <0.01) depending on high variation on mAs with (r=0.98). CT dose was moderate depending on BMI (r=0.55). ConclusionThere was statistically highly significant variation in effective radiation doses associated with non-contrast CT scan of abdomen and pelvis. The reason for this variation must be avoided.