| dc.description.abstract | All mammography units in the country, totaling fourteen in number at the time, were
evaluated on the basis of performance and practice to come up with useful data for
summing up the mammography practice in Kenya. This data could also assist in
drawing up national guidance dose reference levels (DRLs) for this practice.
The study was carried out by performing hands-on quality control tests on the units
using internationally established protocols. Image quality and dose measurement data
were generated in all the centers and they clearly indicated that the practice of
mammography and more so from the optimization point of view, vary from one unit
to another. A standard method was used to obtain these data by use of mammography
accreditation phantom. Data from actual patients were also collected in three major
centers in Nairobi.
One critical observation made on the variations in image quality and breast dose is the
lack of standardized quality control practices in mammography sites in Kenya. Audit
inspections done by the Radiation Protection Board (RPB) are not enough to sustain
the delicate nature of quality that is required in a mammography set up. Moreover,
audit inspection requirements of the RPB have traditionally placed mammography
units in the same category as other radiographic equipment.
Ten out of fourteen units satisfied the criteria used for evaluating phantom image
quality. The average glandular dose was 2.79 mGy per cranio caudal (cc) view of the
phantom and 3.27 mGy per cc view for the sampled patients. The internationally
recommended dose level for such a view is 3.0 mGy. Most units failed in one of the
easiest test of mammographic unit assembly. Of most concern was the lack of
technique charts for the practice detailing the imaging parameters being employed for
the procedure.
However, based on the results of this study, the DRL value may be set to be equal to
2.8 mGy on a cranio caudal view of a unit operating on maximum acceptable
conditions. This value is subject to revision as soon as the practice is improved
considerably.
Based on the results of this study, feasibility of screening program is not justified with
respect to radiation risk as well as considering broader issues of benefit and the cost.
Studies of benefits versus risk need to be carried out exhaustively and objectively.
They are important to major medical organizations, medical insurance companies and
government agencies in formulating guidelines for this practice.
The results of this study indicates that there is need to set up a programme of
optimization of radiological protection in mammography using the experience of
other countries that have put in place quality assurance programs, setting and adoption
of DRLs as part of QA. This practice needs an effective quality control program
which should start with the selection of appropriate equipment for mammography and
the use of qualified personnel including the radiologist, radiographer and the medical
physicist each of whom must participate actively in mammography QC. | en |
