Estimation of diagnostic reference levels for pediatric head computed tomography in Yaoundé.

The diagnostic reference levels (DRLs) are determined from dosimetry studies to compare and manage patient doses in medical imaging procedures. The aim of this work was to establish the first DRLs for pediatric patients during the most common computed tomography (CT) procedures in Yaoundé, Cameroon during routine head CT examinations to know how to improve our clinical practice tomorrow. The sample was classified per age group: ≤ 1-, 1-5-, 5-10- and 10-15-y-old. The retrospective study was used. The proposed DRLs were defined as 75th percentile of the median values of the distributions. In terms of Volume CT Dose Index (CTDIvol) and dose length product (DLP), the DRLs obtained for the ages groups were: 28.6 mGy and 545.8 mGy.cm, 32.6 mGy and 735 mGy.cm, 37.1 mGy and 761.6 mGy.cm and 44.2 mGy and 1081.2 mGy.cm, respectively. DRLs in Yaoundé for DLP were higher than those of comparison literatures. The Yaoundé CTDIvol was higher than the comparison literatures except for the IAEA (2015) values for the three older age groups. The DRLs reported in Yaoundé were compared to Morocco 2020, Switzerland 2018, IAEA 2015 and Iran 2020 values. The estimation of this first DRL for pediatric head CT scan in Yaoundé must be a starting point to spread this investigation towards other examinations and imaging modalities across the country. Therefore, optimization of the CT scan procedures and orderly updates of local DRLs are necessary to improve radioprotection.

ESTABLISHMENT OF LOCAL DIAGNOSTIC REFERENCE LEVEL FOR ROUTINE PAEDIATRIC COMPUTED TOMOGRAPHY EXAMINATIONS IN BAFOUSSAM WEST CAMEROON.

The main purpose of this study was to determine local diagnostic reference level (LDRL) for routine computed tomography (CT) examination in Bafoussam, western Cameroon. The exposure parameters and dose quantities were collected manually. This retrospective, evaluative and comparative study was conducted to determine LDRLs for routine head CT examination in Bafoussam, to optimize these procedures in the region. The 75th percentile values of the calculated volume CT dose index (CTDIvol) and dose length product (DLP) were proposed as LDRL. The sample was classified in four age groups: < 1, 1-5, 5-10 and 10-15 y. The LDRLs obtained for the four age groups were: 24 mGy and 381.32 mGy.cm, 42.5 mGy and 875.55 mGy.cm, 45.85 mGy and 939.62 mGy.cm, 57.12 mGy and 1222.3 mGy.cm, respectively. The 75th percentile CTDIvol and DLP dose values for this study are higher than international values. We propose a coordinating discussions and collaboration about patient's and specific equipment's change information's, between radiologists, medical imaging technicians and medical physicist, which can reduce absorbed doses and improved medical practice in hospitals.

Optimization of pediatric CT scans in a developing country.

BACKGROUND: The purpose of this study was to assess scan parameters and to propose strategies to optimize the examinations of children (from 0 to 15 years old) on adult scanners in developing countries. METHODS: A study was done in 2015 and 2018 on 312 pediatric patients to verify improved practices. The study of 2015 ended with proposed strategies. Dose and scan parameters were available for prospective dose analysis. These strategies were implemented in a study of 2018. RESULTS: Amount the CT examinations study in this paper, the common was head trauma (90 %). For every pediatric CT scan in 2015, a kV of 120 was used in the various hospitals. The mAs ranged from 57.75 to 283.33, slice thicknesses from 1.25 to 2.5 mm and pitch from 0.525 to 1.375 mm. In the study of 2018, implementing the strategy defined in the methodology and proposed in 2015: CTDIVol decreased by 21.27 % for children < 1 year, 31.97 % for children 1-4 years, 17 % for children 5-9 years. DLP also decreased by 25.14 %, 36.29 % and 19.85 % for children < 1 year, 1-4 years and 5-9 years respectively. Children were exposed to ionizing radiation on machines designed for adults, but now the doses received by children are reduced. CONCLUSIONS: The reduction of doses during the pediatric CT examination is possible with the introduction of new optimization protocols or the acquisition of a new machine with a pediatric protocol.