Controversial data have been published on the amount of radiation exposure during radial coronary procedures. We hypothesized that in the current era, high-volume operators with optimal technique would not be exposed to higher radiation doses during radial procedures. A total of 297 patients undergoing cardiac catheterization (195 elective diagnostic coronary angiograms and 102 elective coronary interventions) were prospectively assigned in a random fashion to the radial access (RA) or femoral access (FA). All procedures were performed by the same operator with vast experience in radial procedures and standard measures for radiation protection were used. Operator radiation exposure was measured with an electronic radiation dosimeter attached to the breast pocket of the operator on the outside of the lead apron and estimates of the ambient dose equivalent were derived. For coronary angiograms, fluoroscopy time (2.8 +/- 2.1 vs. 1.7 +/- 1.4 min; P < 0.001) and dose-area product (15.1 +/- 8.4 vs. 13.1 +/- 8.5 Gy x cm(2); P < 0.05) were increased by 18% and 15%, respectively, for RA vs. FA. Operator radiation exposure was 100% higher for the RA compared to the FA (64 +/- 55 vs. 32 +/- 39 microSv; P < 0.001). For coronary interventions, fluoroscopy time (11.4 +/- 8.4 vs. 10.4 +/- 6.8 min; P = NS) and dose-area product (46.3 +/- 28.7 vs. 51.0 +/- 29.4 Gy x cm(2); P = NS) for RA and FA were not statistically different. However, operator radiation exposure was increased by 51% for the RA compared to the FA (166 +/- 188 vs. 110 +/- 115 microSv; P < 0.05). This study demonstrates that the radial approach is burdened with a 100% increase in operator radiation exposure during diagnostic coronary catheterization procedures and a 50% increase during coronary interventions, provided that no special devices for radiation protection are used. Measurements of radiation dose, such as fluoroscopy time and dose-area product, substantially underestimate the disproportionate rise in radiation exposure. Special precautions are warranted to improve radiation protection during invasive coronary procedures via the radial approach.

Personnel dose in diagnostic radiology is often underestimated. Typically the effective dose E is estimated based on dosimeters worn underneath the protective clothing measuring the personal dose equivalent Hp(10). This one-spot-measurement systematically neglects the exposure to the unshielded organs in the head and neck region. In this paper, energy dependent double dosimetry algorithms in the range of 30-80 keV are derived using organ dose conversion coefficients. The doses of shielded organs are assigned to a single dosimeter in the anterior thoracic region (chest) underneath the apron (Hp,c,u), and the doses of the organs not shielded are assigned to another dosimeter placed on the front area of the neck over the protective garment (Hp,n,o) with E = a1 Hp,c,u(10) + a2 Hp,n,o(10). Organs not completely shielded are categorized correspondingly. The coefficients a1 and a2 increase with higher energies up to 70 keV. The factors a2 are clearly higher according to ICRP 103 (rather than ICRP 60) because ICRP 103 considers additional organs in the head and neck region. According to ICRP 103, a conservative general algorithm with thyroid protection is E = 0.84 Hp,c,u(10) + 0.051 Hp,n,o(10) and without thyroid protection E = 0.79 Hp,c,u(10) + 0.100 Hp,n,o(10).

Pelvic lead shielding is highly effective in reducing operator radiation exposure for radial as well as femoral procedures. However, despite its use, radial access remains associated with a higher operator radiation dose.

The revision of the parameters for effective dose calculation leads to higher doses and greater sex-specific differences for radiological examinations involving exposure of the breast. This effect should be considered when justifying any radiological examination. For the personnel, the new model results in higher effective doses due to increased emphasis on the organs in the head and neck region. Hence to optimize radiation protection of personnel, the use of radiation-protective shielding for this region becomes more important.

Optimization of radiation protection devices for the operator is achieved by minimizing the effective dose (E) on the basis of the recommendations of Publications 60 and 103 of the International Commission on Radiological Protection (ICRP). Radiation exposure dosimetry was performed with thermoluminescence dosimeters using one Alderson phantom in the patient position and a second one in the typical position of the operator. Various types of protective clothing as well as fixed leaded shieldings (table mounted shielding and overhead suspended shields) were considered calculating E. Shielding factors for protective equipment can readily be misinterpreted referring to the reduction of the effective dose because fixed protective barriers as well as radiation protection clothing are shielding only parts of the body. With the ICRP 103 approach relative to the exposure without lead protection, a lead apron of 0.35 or 0.5 mm thickness reduces E to 14.4 or 12.3%, respectively; by using an additional thyroid collar, these values are reduced to 9.7 or 7.5%. A thyroid collar reduces the effective dose by more than an increase of the lead equivalency of the existing apron. Wearing an apron of 0.5 mm lead-equivalent with a thyroid collar and using an additional side shield, E decreases to 6.8%. Using both a fixed side and face shield decreases E to 2.0%. For protective garments including thyroid protection, the values of the effective dose in cardiac catheterization are 47-106% higher with ICRP 103 than with ICRP 60 recommendations. This is essentially caused by the introduction of new factors for organs in the head and neck region in ICRP 103.