Neuroembolization may expose patients to radiation doses previously linked to tumor induction

Epidemiological studies indicate a link between low-dose irradiation (<10,000 mGy) to the head and the local occurrence of tumors after decades of delay. Comparable radiation doses can be reached during neuro-endovascular procedures (NEP), but the incidence of similar exposures has not been completely delineated. We compared the levels of radiation to the head measured during NEP to those reported for patients developing radiation-induced cancers.

In our prospective study we determined the cumulative maximum entrance skin doses (MESD) and the incidence of epilation in 107 consecutive patients submitted to NEP between 2003 and 2007. We also extensively searched the literature and compared our results with the data we found.

The cumulative MESD due to NEP was above 3,000 mGy (range 3,101-5,421 mGy) in 18 patients. In 22 we observed partial epilation within 10 weeks from the initial NEP. Sixty cases of epilation after NEP have been previously reported in the literature. The average of the reported MESD was 4,241 mGy (range 2,000-6,640 mGy).

Physical dosimetry and the incidence of partial epilation indicate that about one fifth of the patients submitted to NEP received radiation doses comparable to those linked to the occurrence of tumors. The potential risks of developing tumors after a long delay, when compared to the immediate benefits of endovascular treatment of aneurysm and arteriovenous malformations (AVM) of the brain, do not counterindicate NEP, but increased awareness of the risk should help physicians and patients to make a fully informed decision when other treatments are available.