Local organ dose conversion coefficients for angiographic examinations of coronary arteries.

New organ dose conversion coefficients for coronary angiographic interventions are presented, as well as dose distributions and resulting maximal local dose conversion coefficients in the relevant organs. For the Monte Carlo based simulations, voxel models of the human anatomy were employed which represent the average Caucasian adult man and woman as defined by the International Commission on Radiological Protection. In the 21 investigated projections, the mean organ dose conversion coefficients vary from a few 0.01 to 2 mGy(Gy cm(2))(-1), depending on the projections. However, especially in portions of the lungs and the active bone marrow, the conversion coefficients can locally amount up to 10 mGy(Gy cm(2))(-1), which is half the average conversion coefficient of the skin at the field entrance. In addition to the dose conversion coefficients, the dependence of the patient dose on the projection has been estimated. It could be shown that the patient doses are highest for left anterior oblique views with strong caudal or cranial orientation. Nevertheless, for a large range of image-intensifier positions no significant dose differences could be found.