OA202] Recent update of typical effective doses received by patients at diagnostic and interventional radiology procedures and its impact on assessment of collective effective dose to population in bulgaria

Abstract

Purpose Performance of regular national patient dose surveys is required by European and International Basic Safety Standards and by National law. Third national patient dose survey (TNS) was conducted in 2016–2017 with aim of updating information on radiation exposure to patients at different diagnostic and interventional radiology (DIR) procedures. The purpose of this work is to assess and update typical effective doses received by patients at various diagnostic and interventional radiology procedures (DIR) and to find its impact on assessment of collective effective dose to population. Methods Values of typical patient doses (TPD) are based on data obtained during TNS. Typical effective dose (TED) for each procedure was calculated using conversion coefficients (CC) from TPD to effective dose (E) with dimensions: (mSv. Gy - 1 . cm - 2 ) for radiography, fluoroscopy and interventional procedures; and (mSv. mGy - 1 . cm - 1 ) for Computed tomography procedures respectively. Values of CCs are based on UNSCEAR recommendations, as for Chest radiography an own CC assessment is made based on kerma area product values and respective E values calculated using PCXMC software. Total collective effective dose to Bulgarian population ( S E ) and the effective dose per capita were calculated based on the number of the most frequent DIR procedures and the TED per procedure. Results TED are updated for 16 of most common DIR procedures of which: 5 are radiography; 4 – fluoroscopy; 4 – computed tomography; 2 – interventional cardiology and one is for mammography respectively. For year 2016 SE is assessed to 5868 man.Sv which relates to mean effective dose of 0.82 mSv per capita. It is 16.8% higher than its relevant assessment based on older information for not updated typical patient doses obtained during previous national survey performed in 2007. An increase of 84% in S E is observed for the period of 2007 to 2016 year, as dynamics of collective effective doses is analysed and discussed. Conclusions Updated assessments of TEDs and SE due to DIR procedures are elaborated. Regular patient dose surveys are important for update of National Diagnostic Reference Levels (NDRLs) as well as for obtaining more realistic and precise assessment of collective effective dose to population due to diagnostic radiology procedures.