A survey of the state of mammography practice in Bulgaria.

The purpose of this work is to compare the state of a representative number of mammography systems in Bulgaria in terms of incident air kerma (IAK) and film optical density (OD) and to propose the optimisation measures where appropriate. IAK with a standard phantom and OD of the exposed films were measured on 22 % of all units in the country. IAK values ranged from 2 to 24.3 mGy, with the median being 7.9 mGy, first and third quartiles respectively being 5 and 11.2 mGy and the mean 8.6 mGy. OD values ranged from 0.5 to 2.4. Only 36 % of all units had OD within the recommended range. Only 27 % were satisfactorily set with OD within the recommended range and IAK below the third quartile. Full quality control (QC) measurements on 12 units showed a lot of problems. The observed big variations of IAK, with а factor of 12, are due to the non-optimised settings and film processing, the lack of standardisation and periodical QC. Corrective actions were recommended to optimise the settings of some systems and to improve the practice.