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Instructional course yielded reductions in patient radiation dose
Clinicians who attended an educational 90-minute mini-course in lower-irradiating cardiac invasive techniques reported reductions in radiation dose to patients, according to recent findings.
The researchers cited high radiation exposure levels in invasive cardiology as the reason for attempting to validate the mini-course.
The initial study group included 177 interventional cardiologists from 32 centers in Germany. The interventional cardiologists documented radiation parameters for 10 coronary angiographies before and at a median of 3.7 months after attending the mini-course. Outcomes included dose area product, radiographic and fluoroscopic fractions, fluoroscopy time and number of radiographic frames and runs.
The final analysis included data for 154 interventional cardiologists who reported significant reductions in the median overall dose area product among patients, from a median of 26.5 Gy X cm2 at baseline to 13.7 Gy X cm2 (–48.4%; P<.001).
Reductions in fluoroscopy times (–20.8%), radiographic runs (–9.1%), frames/run (–18.6%) and frames (–29.6%) also were reported among cardiologists who attended the mini-course, along with reductions in both radiographic dose area product/frame (–27.4%) and fluoroscopic direct area product per second (–39.3%). The researchers suggested that these outcomes may indicate improvements in collimation, reduced-irradiation angulations or image quality that is adequate.
Univariate analysis results indicated no significant changes in dose-related parameters among the 23 interventional cardiologists who were invited to the mini-course but failed to attend.
The mini-course was deemed to be effective overall, according to multilevel analysis results (–14.7 Gy X cm2; P<.001). Results of this analysis also indicated higher dose area product for increasing BMI (+1.5 Gy X cm2 per kg/m2); among men (+5.8 Gy X cm2); for increases in age (+1.5 Gy X cm2 per decade) and for flat-panel detector systems compared with older, traditional image intensifier systems (+9.0 Gy X cm2). This last increase may be attributed to different settings during image acquisition, according to the researchers.
Charles E. Chambers, MD, of the Heart and Vascular Institute at Penn State Hershey Medical Center in Hershey, Penn., suggested in an accompanying editorial that assessing radiation dose may require more than just fluoroscopy time.
“Steeper angulations, larger patients, varying frame rate, ignoring store, fluoroscopy mode and patient extremities in the field of view all will significantly increase the dose without affecting fluoroscopy time,” he wrote, adding that the strict regulations for fluoroscopic equipment sold in the United States have been “sporadically instituted among the states.”
Chambers suggested that training sessions for this equipment should include didactic and hands-on tutorials that are updated annually.
“However, an essential component to this study, as it applies to mandatory training for the interventional cardiologist, lies in the operators that ‘chose’ not to take the course,” Chambers wrote. “The potential benefits for all operators, no matter what skill level (achieved or perceived), to be thoroughly trained in radiation safety with regular updates should not be understated. The goal of interventional cardiologists is to do the best for their patients, and in so doing, protect the staff and themselves. In the multitask environment of the cardiac catheterization laboratory, mandatory radiation safety training, with annual updates, will allow all operators, new and experienced, to achieve this goal throughout their career.”
Interventional cardiologists are encouraged to establish radiation safety programs for laboratories and document participation in those programs. They should acquire equipment with dose-limiting capabilities and use it appropriately.
Chambers added that cardiologists should personally protect themselves with shielding above and below table and protective garments and glasses. Dosimetry badges should be mandatory.
Clinicians should also “manage radiation dose throughout the case, not just upon high-dose notification,” he wrote. They should establish parameters for follow-up for all patients.
“When a radiation-conscious environment has been established in the cardiac catheterization laboratory, the patients, staff and physicians will all benefit,” Chambers wrote.
For more information:
Chambers CE. J Am Coll Cardiol Intv. 2014;doi:10.1016/j.jcin.2013.11.015.
Kuon E. J Am Coll Cardiol Intv. 2014;doi:10.1016/j.jcin.2013.11.016.
Disclosure: The researchers and Chambers report no relevant financial disclosures.