Skin dose measurements on patients for diagnostic and interventional neuroradiology: A multicentre study

In Belgium, the number of interventional neuroradiology procedures for the treatment of vascular lesions in the brain and neck region is increasing. These procedures, however, are associated with high doses of X rays. The present study reports on the skin dose measurements on patients undergoing these procedures. Grids of thermoluminescence dosemeters were attached on the head of the patient. The exposure parameters of the X-ray systems and the clinical procedures were fully documented. We searched for correlations between these parameters and the skin doses. While for the diagnostic procedure, the dose threshold of 2 Gy for deterministic effects was not reached, this situation was much different for the embolisations. For angiography of the carotid arteries, no skin doses were measured > 320 mGy. For the cerebral embolisations, maximum skin doses up to 5.4 Gy were measured. Doses to the patients varied largely between different hospitals and within the same hospital for similar procedures. On the one hand, the complexity of the pathology for interventional procedures was responsible for the large variability in dose. On the other hand, large differences in clinical protocol and technical parameters of the X-ray systems, explaining the dose variations, were also observed. A correlation was found between the maximum skin dose measured on a patient and the total dose-area product (DAP) value for cerebral embolisations. This correlation makes it possible to estimate the maximum skin dose from these DAP values and to determine a trigger level. In conclusion, management of patient doses in interventional radiology requires training, specialisation and well-documented procedure guidelines.