X-ray dose to the skin in patients undergoing percutaneous transluminal coronary angioplasty

Dose measurements were performed with an ionization chamber placed on the s urface of a polystyrene phantom to estimate the radiation dose to the skin from fluoroscopy in patients undergoing PTCA and to define parameters predi cting for high-risk irradiation conditions. Dose rate changes were analyzed as a function of phantom thickness, X-ray source-to-phantom distance, imag e intensifier-to-phantom distance, and field size. Skin dose calculations w ere made in 38 PTCA patients to validate the model. Thickness was the most important factor determining dose rate changes in the phantom's surface. Do se rate increased by a factor of almost 4 with each 10-cm increment in thic kness, doubled upon decreasing the field diameter from 17 cm to 14 cm, and increased by a factor of 1.2 to 1.8 upon decreasing the source-to-phantom d istance or by increasing the image intensifier-to-patient distance. All the se parameters may significantly increase the dose to the skin and augment t he risk for skin injuries post-PTCA. (C) 2000 Wiley-Liss, Inc.