Optimisation of X-ray examinations in Lithuania: start of implementation in mammography.

Optimisation of medical X-ray examinations is very important for the enhancement of the reliability of the examination and for the reduction of the radiation dose to patients. Results of investigations of doses to patients during mammography using thermoluminescence dosemeters at different hospitals are presented together with a brief overview of the situation for mammography in Lithuania. It is shown that the entrance surface air kerma varies in a broad range and differed from hospital to hospital. Nevertheless the calculated values of average glandular dose (AGD) for a 'standard' breast being relatively high were comparable with those (3.2 mGy per exposure at net optical density 1.4) currently accepted by international authorities. Differences in AGD values evaluated at different hospitals demonstrate the existing potential for optimisation of the mammography screening procedures. The results of this investigation will be included in a database for patient doses in Lithuania and used for establishing a national reference dose level for mammography. Currently, reference levels recommended by international authorities are used in Lithuania.