Short Safety Course for Operators Lowers Radiation Dose for Patients

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In addition to the mandatory radiation safety training required by institutions, participation of interventional cardiologists in an adjunct 90-minute course substantially reduces patient dose, reports a German study published online March 19, 2014, ahead of print in JACC: Cardiovascular Interventions.

Eberhard Kuon, MD, of Fraenkische Schweisz (Ebermannstadt, Germany), and colleagues invited 177 experienced interventionalists from 32 German centers to participate in the 90-minute in-house course on radiation safety, called ELICIT (Encourage Less-Irradiation Cardiac Interventional Techniques), from 2003 to 2009. A total of 154 physicians completed the voluntary workshop, while 23 cardiologists at 13 centers could not participate “due to daily duties, illness, vacation, and so on, including assumedly some colleagues who considered themselves already experienced enough in dose-optimized interventional practice,” according to the paper.

During a median period of 3.7 months, the research team documented outcomes of 10 consecutive, elective femoral procedures for all interventionalists. Median overall dose area product (DAP) delivered to patients during coronary angiography performed by participants decreased by 48.4%. Additionally, the concomitant reduction of radiographic DAP by 48.7% resulted from both fewer and shorter radiographic runs and better collimation, or accuracy (table 1).

Table 1. Median Outcomes in Patients of Participating Operatorsa

 

Before Course

After Course

DAP, Gy x cm2

26.5

13.7

Radiographic DAP, Gy x cm2

19.7

10.1

Radiographic DAP/frame, mGy x cm2

27.7

20.1

Radiographic Frames

726

511

Radiographic Runs

11

10

Fluoroscopy Time, seconds

159

126

a P < 0.001 for all.


Cardiologists who were unable to attend the course started from a lower overall baseline DAP level. However, the achieved dose-related parameters did not change in univariate comparison.

Multivariable analysis revealed higher DAP fractions and dose intensities to be correlated with higher BMI, older age, and male sex (P < 0.001 for all). It also confirmed the effect of the course on DAP (-14.7 Gy x cm2) and all dose-influencing interventional variables.

“The positive correlation of BMI, age, and male sex with DAP fractions and dose intensities confirms our prior expectations and reflects the necessity of more runs and longer fluoroscopy times with advancing age (which, in turn, result from the increasing complexity of expected coronary heart disease),” Dr. Kuon and colleagues write. “Despite their technical radiation-reducing potential—including fluoroscopy-free collimation, heart rate adaptive selection of pulse rate, and the radiation-saving detector technology itself—the advanced, new-generation catheterization systems clearly generated higher radiographic DAP.”

Changing Operator Priority a ‘Key Challenge’

The authors say that the “key challenge of any radiation protection initiative” will be implementing as-low-as-reasonably-achievable principles in dose evaluation “as part of operator’s attitudes and daily practice.” This will require “ongoing and unreserved cooperation of physicists and cardiologists in every catheterization library,” they write.

In an accompanying editorial, Charles E. Chambers, MD, of Penn State Hershey Medical Center (Hershey, PA), comments, “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.”

He outlines the leadership responsibilities of the interventional cardiologist:

  • Establish a radiation safety program incorporating the physicist
  • Require and document the appropriate initial and ongoing radiation safety training
  • Purchase and properly operate imaging equipment with dose-limiting capabilities
  • Use all available above and below table shielding as well as personal protective garments and glasses
  • Mandate the wearing of the dosimetry badge
  • Manage radiation dose throughout the case
  • Establish follow-up parameters with policies for patients receiving high radiation doses

Stephen Balter, PhD, of Columbia University Medical Center (New York, NY), agreed, adding that practitioners “tend to relax [about training] unless they are reminded periodically.” At his institution, Dr. Balter said, he runs an annual refresher conference for cath lab personnel, which has contributed to a 35% reduction in “our all-comers dose” over 4 years.

Durability of Education Still an Issue

Dr. Balter said the study outcomes are reasonable but questioned the durability of the single course, adding that a 1-year follow-up study of the participating operators without any additional retraining would be helpful to know.

Additionally, he said, future research should focus on determining if “the training could be done with less consumption of physician time,” especially given that all participants in the study had already gone through the mandatory 8-hour German safety training program.

“One of the problems is the complexity of the procedures is growing and eventually you can’t reduce the radiation any further without compromising the medical benefits,” Dr. Balter explained. “So the instructors have to be sensitive to the fact that the physicians are actually trying to take care of sick people. The radiation should be good enough so that the clinical care is not compromised, but not necessarily any better.”

Study Details

A total of 26 centers used older, traditional image-intensifier catheterization systems, and 6 centers employed advanced new-generation flat-panel acquisition systems. Each interventionalist was instructed to use the same equipment before and after the course.

 


Sources:
1. Kuon E, Weitmann K, Hoffmann W, et al. Efficacy of a minicourse in radiation-reducing techniques in invasive cardiology: a multicenter field study. J Am Coll Cardiol Intv. 2014;Epub ahead of print.

2. Chambers CE. Mandatory radiation safety for fluoroscopy imaging: a quality improvement priority or unnecessary oversight? J Am Coll Cardiol Intv. 2014;Epub ahead of print.

 

 

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Disclosures
  • Drs. Kuon, Chambers, and Balter report no relevant conflicts of interest.

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