Evaluation of Local Diagnostic Reference Levels for Paediatric and Adult Patients Undergoing Head Computed Tomography Examination in Amhara Regional States, Ethiopia

Introduction: During computed tomography examinations variation of dose for pediatric and adults has been increasing widely, even when automated exposure control is used. Hence, the objective of this study was to assess the computed tomography head local diagnostic reference levels in the Amhara region.Material and Methods: Active computed tomography scanners in the Amhara region were identified and then both retrospective and prospective technique was used to collect data for pediatric and adult head examinations. Scan parameters, patient profiles, and CT dose indicators were collected from ۳۳۴ patients.  Pediatric patients were grouped into three age (years) groups of (۱-۵, ۵-۱۰, and ۱۰-۱۵). The local diagnostic reference levels were established from third quartile values of computed tomography dose index and dose length product. SPSS software version ۲۶ and Microsoft Excel ۲۰۱۶ were used for the entire data analysis.Results: The calculated ۳rd quartile values  of computed tomography dose index and dose length product, for adult head examinations, were ۴۹ mGy and ۱۸۰۶ mGy.cm respectively. Similarly, for pediatric head CT scan, computed tomography dose index (mGy) and dose length product (mGy.cm) values for age (years) groups (۱-۵, ۵-۱۰, and ۱۰-۱۵) were (۳۰, ۲۰۱۵); (۳۵, ۱۲۲۱); and (۴۳, ۲۰۵۱) respectively.The investigated ۳rd quartile values of computed tomography dose index and dose length product were higher than other national and international reported values.Conclusion: For all pediatric and adult patients , there are differences in the local diagnostic reference levels between the CT centers and the same scanners, indicating the need for dose optimization.

Keywords:

computed tomography dose index , dose length product , Radiation Exposure Parameters