Radiation exposure during percutaneous coronary interventions and coronary angiograms performed by the radial compared with the femoral route.

OBJECTIVES: This study aimed to compare radiation exposure of patients undergoing percutaneous coronary interventions (PCI) and coronary angiograms (CAG) accessed by the femoral route with the radial route (operator's choice). BACKGROUND: There are limited and contradictory data on the radiation exposure of patients during PCI and CAG performed by the radial route compared with the femoral route. METHODS: Data on the radiation exposure of patients from 3,973 PCI and CAG procedures between June 22, 2004, and December 31, 2008, were prospectively collected and analyzed. A prediction model was made for radiation exposure (dose-area product in Gy·cm(2)) based upon the femoral access group, and the group of radial performed procedures was compared to assess differences between observed and expected radiation exposure. RESULTS: Median exposures of patients undergoing a PCI via the femoral route (n = 2,309) was 75 (interquartile range [IQR]: 44 to 135) Gy·cm(2) compared with 72 (IQR: 42 to 134) Gy·cm(2) for radial performed procedures (n = 1,212) (p = 0.30). Median exposure for CAGs was 44 (IQR: 31 to 69) Gy·cm(2) and 40 (IQR: 25 to 65) Gy·cm(2) for, respectively, femoral (n = 314) and radial performed procedures (n = 138), (p = 0.31). Also, the observed radiation exposure in patients undergoing radial PCI or CAGs was not higher than the expected exposure of patients as predicted by the femoral access-based prediction model (71.5 ± 2.3 Gy·cm(2) vs. 79.9 ± 1.8 Gy·cm(2,)). CONCLUSIONS: The study shows that even after correction for the complexity of the procedures, selected procedures performed by the radial route are not associated with higher radiation exposure of patients than selected procedures performed by the femoral route.

Exposure of cardiologists from interventional procedures.

Data on the exposure of seven cardiologists and over 10 000 patients undergoing interventional procedures were collected. The data were collected in a study that was set up to evaluate differences in the exposure of seven cardiologists performing interventional procedures. The study revealed a linear relation between the exposure of the seven cardiologists and the exposure of their patients (R(2) = 0.55). The exposure of the cardiologists ranged from 0.43 to 2.85 mSv in 4 weeks, while for the patients the exposure ranged from 1633 to 5943 Gy cm(2) in 4 weeks. It was concluded that the height of the doses of the cardiologists is associated with the number of procedures, not with the complexity of the procedure. In order to reduce the exposure of cardiologists, it is recommended to optimise the exposure techniques.

Effective dose to staff from interventional procedures: estimations from single and double dosimetry.

The exposure of 11 physicians performing interventional procedures was measured by means of two personal dosemeters. One personal dosemeter was worn outside the lead apron and an additional under the lead apron. The study was set up in order to determine the added value of a dosemeter worn under the lead apron. With the doses measured, the effective doses of the physicians were estimated using an algorithm for single dosimetry and two algorithms for double dosimetry. The effective doses calculated with the single dosimetry algorithm ranged from 0.11 to 0.85 mSv in 4 weeks. With the double dosimetry algorithms, the effective doses ranged from 0.02 mSv to 0.47 mSv. The statistical analysis revealed no significant differences in the accuracy of the effective doses calculated with single or double dosimetry algorithms. It was concluded that the effective dose cannot be considered a more accurate estimate when two dosemeters are used instead of one.

Evaluation of the occupational doses of interventional radiologists.

The aim of the present study was to determine whether there is a linear relation between the doses measured above and those measured under the lead apron of the radiologists performing interventional procedures. To monitor radiation exposure the International Commission of Radiological Protection (ICRP) recommends the use of a single dosimeter under the protective apron. To determine the exposure more accurately an additional dosimeter is recommended above the protective apron. The exposure of eight radiologists was monitored with two personal dosimeters during 3 consecutive years. To measure the doses uniformly the two dosimeters were worn in a special holder attached to the lead apron. The two personal dosimeters were replaced every 4 weeks on the same day. The doses above and under the protective aprons of seven radiologists did not differ significantly. A significant lower dose above and under the protective apron was measured for one of the radiologists. During a 4-week period the average dose measured above the lead apron was 3.44 mSv (median, 3.05 mSv), while that under the 0.25-mm lead apron was 0.12 mSv (median, 0.1 mSv). The coefficients of the regression line result in the equation Y = 0.036X-0.004, with Y as the dose under the lead apron and X as the dose above the lead apron. The statistical analysis of the data established a linear relation between the doses above and those under the lead apron (R(2) = 0.59). Before the special holder was introduced it was not possible to derive a relation between the doses above and those under the lead apron, as the doses were measured at varying places above and under the lead apron. There is no evidence that the effective dose can be estimated more accurately when an additional dosimeter is used. The present study revealed a threshold before doses under the lead apron were measured. Due to the threshold it can be concluded that the doses under the lead apron will not be underestimated easily when doses above the lead apron are used to calculate them. This is not the case when the doses above the lead apron are calculated for the doses under the lead apron.