Ingrid M. Burger MD, PhD, Presenter: Nothing to Disclose

Diana Miglioretti PhD, Abstract Co-Author: Nothing to Disclose

Eric Johnson, Abstract Co-Author: Nothing to Disclose

Nicholas Vanneman, Abstract Co-Author: Nothing to Disclose

Rebecca Smith-Bindman MD, Abstract Co-Author: Nothing to Disclose

Despite recent dramatic increases in diagnostic imaging, little is known about trends in radiation exposure, particularly in cancer patients who constitute an imaging-intensive group. This study describes and compares temporal patterns of radiation exposure between cancer and non-cancer patients.

Retrospective cohort analysis of patients enrolled in a large integrated healthcare system. For each enrollee, we determined the individual radiation exposure that year by summing the radiation doses across each imaging study, and evaluated patterns of annual effective dose (ED) over time. Enrollees were characterized as cancer free or having cancer. Among cancer patients, we calculated five-year ED defined as a cumulative ED within the first five years following a diagnosis (diagnosis and treatment period), versus cumulative ED within years 6–10 years following a cancer diagnosis (surveillance period).

Overall, 1,081,923 members underwent 621,022 imaging exams associated with ionizing radiation between 1994 and 2008. Annual EDs per patient increased nearly three fold during this time. The mean annual ED rose from 0.79 to 2.1 mSv in non-cancer patients, and from 5.6 to 14.0 mSv in cancer patients. A small but increasing proportion of patients received particularly high exposures; in 1994, 0.12% of non-cancer patients received an annual ED over 50 mSv, rising to 0.63% in 2008. Among cancer patients, 2.3% received a dose above 50 mSv in 1994, rising to 8.2% in 2008. The mean 5-year ED was 37.8 mSv for cancer survivors years 1–5 after diagnosis, decreasing to 30.8 mSv in years 6–10; and in each group, 10% (treatment period) and 7% (surveillance period) respectively, received 5-year ED doses above 100 mSv. High exposures are seen in cancer patients below 24 years of age; mean 5-year ED was 47.5 mSv at 1–5 years and 15.5 mSv at 6–10 years after diagnosis. In each group, 16% (treatment period) and 3.8%, (surveillance period) respectively, received 5-year ED doses above 100 mSv.

Annual effective dosages from imaging have risen from 1994 to 2008, both in patients with and without cancer. Among cancer patients, EDs remain high even 6 or more years after diagnosis.

These results support the need to track patients’ medical radiation dosage over time, and evaluate the intensity of CT surveillance greater than 5 years after a cancer diagnosis.

Burger, I, Miglioretti, D, Johnson, E, Vanneman, N, Smith-Bindman, R, Radiation Exposure Increased Dramatically in a Large Health Plan, Particularly Among Cancer Patients.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9013342.html Accessed October 10, 2025