| dc.description.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. | en |
