RADIATION-DOSES DURING PEDIATRIC RADIOFREQUENCY CATHETER ABLATION PROCEDURES

Because RF catheter ablation procedures may be lengthy and are commonl y performed in young patients, concern has arisen about radiation dose in this group of patients. This article investigates radiation doses in pediatric patients undergoing RF catheter ablation. Standard fluoro scopic equipment used for diagnostic electrophysiological catheterizat ion studies is technologically capable of dose rates as high as 90 mil ligray (mGy) per minute to skin and adjacent lung and 260 mGy/min to v ertebral bone. Dose rates of this magnitude when used for extended per iods of time have been known to cause erythema, pneumonitis, and retar dation of bone growth. We measured skin dose rates of nine pediatric p atients undergoing RF catheter ablation for tachycardia and calculated doses to the skin using standard dosimetric methods. Fluoroscopic tec hniques and equipment were studied using a patient simulating phantom. Overlap of fluoroscopic fields was checked using radiotherapy portal verification film, and regions in which doses overlapped from multiple angle exposures were verified using a treatment planning computer. Pa tient skin dose rates ranged from 6.2-49 m Gy/min for patients ranging in age from 2-20 years. Maxim um skin doses ranged from 0.09-2.35 Gy Our data demonstrate the need to directly measure dose rates for indiv idual fluoroscopic equipment and procedural techniques in order to det ermine whether limitations need to be set for procedural times.