No abstract

Background-Radiofrequency (RF) cardiac catheter ablation procedures may require extended fluoroscopic exposure resulting in elevated radiation risk. The aim of the present study was to accurately establish RF ablation radiation risk levels and to provide means for accurate patient risk estimation from studies performed in any electrophysiology laboratory. Methods and Results-Fluoroscopy required during cardiac ablation was classified into 4 types identified by beam orientation and irradiated tissue: (1) posteroanterior exposure during catheter advancing from the groin to the heart, (2) posteroanterior heart exposure, (3) left anterior oblique heart exposure, and (4) right anterior oblique heart exposure. The duration of each exposure was monitored in 24 patients undergoing RF cardiac ablation. Dose per minute of fluoroscopy was measured at 15 organs/tissues for each projection with the use of anthropomorphic phantom and thermoluminescence dosimetry. The effective dose rate was 219, 144, 136, and 112 Gy/min for groin-to-heart posteroanterior, posteroanterior, left anterior oblique, and right anterior oblique exposure, respectively. A typical ablation procedure results in a total effective dose of 8.3 mSv per hour of fluoroscopy. The average excess of fatal cancers was estimated to be 650 and 480 per million patients undergoing RF ablation requiring 1 hour of fluoroscopy for US and UK populations, respectively. The average risk for genetic defects was determined to be 1 per million births. Conclusions-Radiation risk from RF cardiac ablation is moderate compared with other complications, but it may highly exceed radiation risk from common radiological procedures. Efforts should be made toward minimization of patient radiation risk from RF ablation procedures. (Circulation. 2001;104:58-62.)

Fluoroscopically guided procedures in the electrophysiology room, such as radiofrequency catheter ablation and implantation of cardiac resynchronization devices, may result in high radiation exposure of electrophysiologists and assisting staff. Our aim was to provide accurate and applicable data on occupational doses to the electrophysiology laboratory personnel. We exposed fluoroscopically an anthropomorphic phantom at three projections common in electrophysiology studies. For each exposure, scattered radiation was measured at 182 sites of the cardiology room at four body levels. Effective dose values, eye lens, skin and gonadal doses to the laboratory staff were calculated. Our study has shown that a procedure requiring 40 min of fluoroscopy yields a maximum effective dose of 129 microSv and a maximum value of gonadal dose of 56.8 microSv to staff using a 0.35 mm lead-equivalent apron. A conservative estimate of the electrophysiologist's annual maximum permissible workload is 155 procedures. Staff effective dose values vary by a factor of 40 due to positioning during fluoroscopy and by a factor of 11 due to radiation protection equipment. Undercouch protective shields may reduce gonadal doses up to 98% and effective dose up to 25%. Consequently, radiation levels in the electrophysiology room are not negligible. Mitigation of occupational exposure is feasible through good fluoroscopy and working practices.

Patient dose and radiogenic risks associated with an average pedicle screw internal fixation procedure are tolerable. However, for young patients with complex spinal disorders requiring extended fluoroscopy, radiogenic risks may be considerable. Present data may beused for estimation of effective dose, gonadal dose, and entrance skin exposure and associated radiogenic risks to patients undergoing fluoroscopically guided pedicle screw insertion in any institution.

Background-The aim of the current study was to estimate the conceptus radiation dose and risk associated with fluoroscopic imaging during a catheter ablation procedure for supraventricular tachycardia performed on the expectant mother. Methods and Results-Exposure parameters and fluoroscopy times for each projection of the cardiac ablation procedure performed in 20 female patients of childbearing age were recorded. Radiation doses for a potential conceptus were estimated by using dose data obtained in anthropomorphic phantoms simulating pregnancy at the first, second, and third trimesters. Dose measurements were carried out using thermoluminescent dosimeters. For a typical examination, the average radiation dose to the conceptus was Ͻ1 mGy in all periods of gestation. Average excess fatal cancer was 14.5/10 6 unborn children irradiated during the first postconception weeks. Corresponding values for the second and third trimesters were 30 and 55.7/10 6 , respectively. The risk for hereditary effects in future generations was 1.5/10 6 cases for conceptus irradiation during the first postconception weeks. Corresponding values for the second and third trimesters were 3.0 and 5.6/10 6 , respectively. Formulas and dose data are presented for estimating the conceptus risk from any technique and x-ray system used for catheter ablation procedures. Conclusions-A typical catheter ablation procedure results in a very small increase in risk of harmful effects to the conceptus. However, estimation of conceptus dose from catheter ablation procedures is always needed to assess the risk to the individual developing in utero.