Evaluation of Patients Doses During 2 and 16 Slice CT Scan Procedure in Adults

Aim: Computed tomography (CT) is an innovation that has contributed immensely to modern medicine. CT uses ionising radiation in the form of x-rays which has become a source of concern. The study is to evaluate patients’ doses during 2 and 16 slices CT scan procedure in adults.

Study Design: The study was an empirical study.

Place and Duration of Study: It was carried out with 50 patients referred for brain CT in two separate radiology facilities having 2 and 16 slices CT scans in Port Harcourt over 6months duration.

Methodology: The examination was done in accordance with standard protocols for brain CT. Radiation dose was measured with a coded themoluminiscent dosimeter (TLD) chip, placed on the glabella and held in position with a transparent adhesive tape before the exposures and removed immediately after the investigation, labeled and sent to the Radiation Dosimetric Laboratory of the Regional Centre for Energy Research and Training (CERT), Zaria for reading. The effective dose was obtained from the absorbed dose by multiplying the absorbed dose with tissue weighting factor of 0.01 for the brain. The cancer and hereditary effects per investigation were obtained by using the cancer risk coefficients (FCR = 5.5X10−2 Sv−1) and hereditary risk coefficients (FGE = 0.2X10−2 Sv−1) obtained from ICRP 103 publication. All variables collated were tabulated into a data sheet and analyzed using Statistical Package for Social Sciences (SPSS) windows version 22.30 statistical software (SPSS Inc, Chicago, Illionois, USA). The results were presented on tables, charts and graphs. A descriptive statistical tool was used to - determine central tendencies while Pearson correlation and linear regression analysis model was used to evaluate correlation between variables.

Results: The mean absorbed dose (±SD) was 51.37(±8.07)mSv and 89.97±13.25mSv during 2 and 16 slices CT procedures respectively. The Lifetime Attributable Risk is approximately 3 and 5 per 105 CT procedures during 2 and 16 slice CT procedures while the Hereditary Risks was 1 and 2 per 106 CT procedures for 2 and 16 slice CT procedures respectively. There was a weak correlation between BMI and cancer risk with a Pearson Correlation coefficient (r) of 0.130 but no association between cancer risk and age during 2 slice CT scanner.

Conclusion: Absorbed dose increases with increase on the CT slices, likewise cancer and hereditary risk increases with increase in CT slices. Thus, notwithstanding how low a radiation exposure could be it can still necessitate malignant risk.