[Development of a new method to estimate patient surface dose distributions in IVR]

Recently, the angiography system used for interventional radiology (IVR) provides a device for measuring dose-area product (DAP), which is compulsory in European countries. The usefulness of DAP is that one can observe patient dose in real time during IVR and can obtain an integral dose by overall IVR procedure without a dosimeter directly placed on a patient. It is important to know the most irradiated region (hot spot) of the patient's skin and its maximum value in the dose management of IVR, but this information cannot be obtained only in DAP. In this paper, we describe a new method to estimate patient surface dose distributions in IVR. We devised a sheet dubbed the "Number map", which does not obstruct the IVR procedure, to confirm the hot spot, and we developed software (named PIETA "Patient Information on Exposure Total Dose Analysis in IVR") to analyze the data from the Number map. Using this system, dose distributions of patient's skin were easily obtained, and we could easily perform patient dose management in IVR.