Determination of Institutional Based Diagnostic Reference Level for Adult Computed Tomography Examination in Nasarawa State, Nigeria

Abstract

Background

Diagnostic reference level is important in checkmating excesses and for dose optimization in medical procedures. It has been proven to be very effective in ensuring that patient dose is within the recommended standard of practice.

Objective

The objective of the work was to find out the dose values in each set of CT examinations and the primary examination parameters for the head, chest, and abdomen in adult patients.

Methodology

The work was a retrospective investigation using a CT scanner that was carried out in two tertiary healthcare facilities in Nasarawa State. The average doses for the pre- and post-contrast examinations were obtained. The machine parameters, scan length, field of view, Dose Length Product (DLP), and Computed Tomography dose index (CTDIvol) were documented. The International Atomic Energy Agency's guidelines for average weighted patients were obtained, and the protocol was appropriately followed. The statistical package for social sciences was used to analyze the data, and the IAEA framework was followed.

Results

The established DRLs are (50.6 mGy & 1079 mGy·m^-1), (15.7 mGy & 522 mGy·cm^-1), and (14.2 mGy & 702.5 mGy·cm^-1) for Head, Chest, and Abdomen respectively. Comparing this study with international studies across the globe for the various body anatomies (Head, Chest, and Abdomen), this study is relatively within the range of variations in the scan protocols used, human errors, and non-coherence to the norms of international best practices.

Conclusion

The local diagnostic reference levels for routine Head, Chest, and Abdomen were established and the CTDI and DLP analysis was done in line with the EC guidelines in all the centers. The estimated values for CTDI_v were similar across the centers and in tandem with the EC value. The mean DLP values were in line with the proposed EC values. The high dose values are attributable to technical parameters, untimely quality control initiatives, work fatigue, the unnecessary use of large scan lengths for the abdominal region, generational gaps of the scanners, and other unwholesome practices.