Total entrance skin dose: an effective indicator of maximum radiation dose to the skin during percutaneous coronary intervention.

OBJECTIVE: A number of cases of radiation-associated patient skin injury during percutaneous coronary intervention (PCI) have been reported. To protect against this complication, maximum skin dose to the patient should be monitored in real time. Unfortunately, in most cardiac intervention procedures, real-time monitoring of maximum skin dose is not possible. Angiographic X-ray units, however, display the patient's total entrance skin dose in real time. We therefore investigated the relation between maximum skin dose and total entrance skin dose to determine whether total entrance skin dose can be used to estimate maximum skin dose during PCI. MATERIALS AND METHODS: The dose-area product was measured, and maximum skin dose and total entrance skin dose were calculated with a skin-dose-mapping software program. The target vessels of 194 PCI procedures were divided into four groups according to the American Heart Association (AHA) segment system. RESULTS: The maximum skin dose constituted 48%, 52%, 50%, and 52% of the total entrance skin dose during PCI on AHA segments 1-3, 4, 5-10, and 11-15, respectively. There were significant correlations between maximum skin dose and total entrance skin dose during PCI (r = 0.894, 0.935, 0.859, and 0.898 for segments 1-3, 4, 5-10, and 11-15, respectively; p < 0.001). CONCLUSION: Maximum skin dose during PCI is approximately 50% of the total entrance skin dose for each target vessel. Correlation between the two doses was very good. Total entrance skin dose is an effective predictor of maximum skin dose during PCI when the formula used is maximum skin dose = 0.5 x total entrance skin dose. Our results provide useful information for avoiding deterministic radiation skin injury to patients undergoing PCI.