FEVAR radiation injury reexamined
In June 2013, the researchers implemented a new policy regarding the follow-up of FEVAR patients, which involved a full skin exam at postoperative week 2 and 4, and at 3 and 6 months, as well as questioning patients about any skin-related complaints. For the current study, they retrospectively reviewed all FEVARs over a 7-month period after the change in policy and highlighted all the cases that reached a RAK of 5 Gy or greater.
Peak skin dose, a dose index, and simulated skin dose maps were calculated using customized software employing input data from fluoroscopic machine logs. Of 317 cases performed, 22 met or exceeded a RAK of 5 Gy. Of these, 21 were FEVARs and one was an embolization. Dr. Kirkwood reported that the average RAK for all FEVARs was 8 Gy, with a range of 5-11 Gy.
Slightly more than half of patients (52%) had multiple fluoroscopically guided interventions within 6 months of their SRDL event. The average RAK for these patients was 10 Gy (range of 5 - 15). The mean peak skin dose for all FEVARs was 5 Gy (range of 2 - 10 Gy), and the dose index was 0.69. The average peak skin dose for the subset of patients with multiple procedures was 7 Gy (a range of 3 - 9 Gy).
In terms of the follow-up, all 21 FEVAR patients were examined at the 1- or 2-week mark, 81% were examined at 1 month, 52% were examined at 3 months, and 62% were examined at 6 months. No radiation skin injuries were reported. “Based on the published data, we would expect to see all grades of skin injury, especially in the cohort of the 5-10 Gy,” Dr. Kirkwood said.
In the previous study, conducted prior to the new follow-up policy, the dose index for FEVARs was 0.78, “meaning that the peak skin dose that the patient received could be roughly estimated as 78% of the RAK dose displayed on the monitor,” Dr. Kirkwood explained.
“In the current work, the dose index decreased to 60%. This suggests that surgeons in our group have now more appropriately and effectively employed strategies to decrease radiation dose to the patient. However, even when the best operating practice is employed, FEVARs still continue to require high radiation doses in order to complete.”
The present study demonstrated that deterministic skin injuries “are uncommon after FEVAR, even at high RAK levels and regardless of cumulative dose,” she concluded. “Even with more comprehensive patient follow-up, the fact that no skin injuries were reported suggests that skin injuries in this patient cohort are less prevalent than the published guidelines would predict.”
Dr. Kirkwood reported no financial disclosures.
