Facility dose reference levels for radiation doses for paediatric head CT examination at Moi teaching and referral hospital.

International Journal of Research and Innovation in Social Science (IJRISS) | Volume VI, Issue III, March 2022 | ISSN 2454–6186

Facility dose reference levels for radiation doses for paediatric head CT examination at Moi teaching and referral hospital.

Tima Nassir¹, Onditi Elias¹, Festus Njuguna², Jack Odunga^3
1Department of Radiology and Imaging, Moi University School of Medicine
² Department of Child Health and Paediatrics, Moi University School of Medicine
³ Department of Reproductive Health, Moi University School of Medicine

ABSTRACT
Objective: To establish facility dose reference levels for radiation doses for paediatric head CT examination at Moi teaching and referral hospital.
Methods: This was a descriptive cross sectional study done at Moi Teaching and Referral Hospital. A total number of 127 patients aged between 0 to 15years were recruited into the study using systematic sampling technique. Data was collected from the Computed tomography console and estimated effective dose calculated. Categorical variables were summarized as frequencies and percentages. Bivariate analysis was done using T-test to test for association between the dependent and independent variables between the groups. Pearson correlation coefficient and scatter plots were used to describe the relationship between the radiation doses, age and Body Mass Index. A P value of <0.05 was considered to be statistically significant.
Results: The mean age for the participants studied was 5.21years. The most common indication for Computed tomography was hydrocephalus (24%). The average Computed Tomography Dose Index, Dose Length Product and effective dose was 32.84 mGy, 1006.1 mGy.cm and 4.01mSv respectively.
The Facility reference level was set as the median value for CTDIVOL, DLP and effective dose at 36.5mGy, 850.6mGy.cm and 3.75mSv respectively.
Conclusion: Computed Tomography Dose Index of the patients are within normal parameters with other places in the world. The Dose Length Product and effective dose are within range with the ones of National Diagnostic Reference Level for Kenya but higher than others countries such as Turkey. There was statistically significant correlation between age and effective dose.

Keywords: Computed Tomography Dose Index, Dose Length Product, Effective dose

BACKGROUND

Globally, most DRL data available are estimated for adults. There is little literature especially in LMICs on DRL for children. An analysis on the comprehensiveness of available data on DRL’s from 1996-2015 found only 53 articles were on CT examination with paediatric DRLs representing 14 (26%) of these articles(Meyer et al., n.d.). The trend in establishing DRLs for LMICs however was shown to be improving with 29 (54%) of articles having been published between 2011 and 2015 [1]. Most DRLS data available is from high-income countries.
In 2010 the IAEA coordinated a project consisting of 3 phases where dose indices based on standard protocols in paediatric CT and technical factors were surveyed. Patient cohorts were divided into four age groups <1year, >1-5years, >5-10years and >10-15years. Data from 82 CT facilities in 72 hospitals from 32 countries were included in the survey. The distribution was 42 CTs in Asia, 30 in Europe, 7 in Africa and 3 in Latin America. The total number of patients used for analysis was 6115. DRLs were set at the 75th percentile of the distribution of mean values. The established DRL for CTDI and DLP for head CT for age groups <1year, >1-5years, >5-10years and >10-15years were 26mGy, 36mGy, 43mGy and 53mGy respectively and 440mGy.cm,540mGy.cm, 690mGy.cm and 840mGy.cm respectively[2].
The UK NDRLs are based on the body region examined. The doses for Paediatric CT examinations were based on 16cm standard CT dosimetry phantom. The set NDRLs for paediatric head CT in the UK are given in age groups where whose CTDIvol per sequence is 25mGy and DLP per complete examination for 0-1year is 25mGY and 350mGycm, for >1-5 years 40mGy and 650mGYcm and >5year 60mGy and 860mGycm respectively[3].

Read More