Assessment of quality assurance in diagnostic radiology in selected hospitals in Nairobi

Abstract

Available data at the Radiation Protection Board of Kenya Laboratories (RPBL), indicates an increasing trend in the installation of medical x-ray facilities in the country, particularly in Nairobi. This is an indication of increased proliferation of medical imaging facilities. A review of the data also indicates that there are no adequate mechanisms in place to ensure production of quality radiographs and low patient radiation dose. The study was carried to investigate the performance of the radiographic machines in some selected hospitals of Nairobi and their compliance with current national and international radiological quality assurance guidelines. A random sampling technique was used to get a reasonable sample size from the data available at the RPBL on the radiological facilities registered in Nairobi. The number of facilities in Nairobi represents approximately 20% of all registered radiological facilities in the country. Our sample was made up of 19 hospitals with 42 installed x-ray machines of different makes and types. The assumptions made were that all requirements pertaining to establishments and operations of typical radiological facility were observed; approval to operate the x-ray equipment from the regulatory authority and that the radiographers were familiar with operations of the equipment and were monitored for exposure regularly. Our assessment was therefore, only directed essentially to basic radiation safety parameters; kilovoltage accuracy, timer accuracy, beam perpendicularity, and radiation output reproducibility, which 1}repart of important parameters for consideration when doing quality control tests. Additional, radiographic sensitometry and image quality tests are recommended for a comprehensive compliance testing program. The following are the adopted tube voltage compliance status of the x-ray generator used throughout in this work: for S 80 kVp values; 8. < ±5.0%; pass 2: ±5.06 S 5.1%; borderline 6 >5 .1%; fail for >80 kVp values; 6 S ± 4kV; pass 2:±4 kV6 S ± 4.1kV; borderline 6 >±4.1 kV; fail The parameters that were analyzed for performance for each of the machine were; kilovoltage accuracy, timer accuracy, beam perpendicularity accuracy and radiation output reproducibility in accordance to quality assurance handbook requirements. The equipment used were; beam alignment test tool, rad-check meter, a film cassette, lead apron, kV meter, a level and a measuring tape.