The influence of patient size on patient doses in cardiology

In cardiology and interventional radiology, areas that contribute large components to medical radiation exposure, a major source of variation in patient dose is the variation in complexity between cases for nominally identical procedures. In patient dose surveys, this variation tends to mask that due to patient size. The effect of applying a previously defined size correction to cardiology patient dose-area product (DAP) records was investigated. The correction method uses the experimentally determined relationship between patient diameter and DAP to derive a factor to convert DAP to that which would be expected had the patient been similar in size to ICRP Reference Man. The size correction was found to greatly reduce the residual correlation of DAP with patient weight. An implication of this finding is that data collection for the setting of diagnostic reference levels in cardiology can be performed for all patients rather than just 'standard-sized' patients. (authors)