Mammography May Be Avoided by Women Who Overestimate Radiation Risk

Overestimation of radiation risk may keep some women from undergoing screening mammograms, therefore preventing early detection, according to a study presented today at the 2014 ARRS Annual Meeting in San Diego, Calif.

Researchers from the University of California, Los Angeles, sought to ascertain how a patient’s knowledge of the ionizing radiation is associated with breast imaging.

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A total of 133 women, ages 19 to 89, completed a questionnaire survey about radiation exposure in which they were asked to rate the amount of radiation in a single mammogram as being significantly less, slightly less, about the same, slightly more or significantly more compared to a series of radiation benchmarks. The women were provided with five benchmarks that were chosen to provide an approximately logarithmic scale centered at the value of a mammogram (0.4mSv):

• The extra dose received from spending two days in Denver (0.006mSv)

• The dose received from an airplane flight from Los Angeles to New York (0.04mSv)

• The average annual dose from food (0.3mSv)

• The average yearly background dose (3.1mSv)

• The limit for a radiation worker per year (50mSv)

“The rank of a mammogram among the six radiation sources was then determined for each subject by counting the number of benchmarks that were rated as having more radiation with 1 being the highest, 6 the lowest, and 3.5 being the correct response,” the authors wrote. The respondents were also asked to report their highest education level obtained and whether or not they believed they had received sufficient explanation of the risks and benefits of a mammogram.

The findings showed that of 78 women who completed the benchmark question, none were able to put the radiation benchmarks in the correct order.  “On average, women significantly overestimated the amount of radiation associated with a mammogram in comparison to other radiation benchmarks,” the authors noted. “The average rank given was 2.9 with a standard deviation of 1.2, which differed significantly from the correct answer of 3.5.” Level of education made no significant difference between those who felt that they had received sufficient explanation and those who did not.

“Our findings indicate a need to educate patients about the amount of radiation they are exposed to during a single screening mammogram,” coauthor Jacqueline Hollada said in a release. “Using everyday sources of radiation exposure as benchmarks can help add perspective and improve patients’ understanding of radiation levels associated with mammography, thereby reducing anxiety related to the examination.”