A trip to your doctor or dentist usually means you will be examined from the inside out. But, low-dose radiation like that used in x-rays, mammograms and other diagnostic tests could be causing some cancers.
There is enough concern that researchers at the National Institutes of Health (NIH) Clinical Center are now incorporating radiation dose exposure reports into their electronic medical records.
It’s an effort the NIH hopes will lead to an accurate assessment of whether any cancer risk is associated with low-dose radiation exposure from medical imaging tests according to an article in the February issue of the Journal of the American College of Radiology (JACR).
But not everyone agrees that exposure to diagnostic medical radiation are unsafe. What’s more, it could be many years before we know for sure.
"The cancer risk from low-dose medical radiation tests is largely unknown. Yet it is clear that the U.S. population is increasingly being exposed to more diagnostic-test-derived ionizing radiation than in the past," said David A. Bluemke, MD, lead author of the article and director of Radiology and Imaging Sciences at the NIH Clinical Center.
Dr. Bluemke notes one widely publicized appraisal of medical radiation exposure suggested that about 1.5 to 2 percent of all cancers in the USA might be caused by the clinical use of CT alone.
A CT scan — also called computerized tomography or just CT — combines a series of X-ray views taken from many different angles to produce cross-sectional images of the bones and soft tissues inside your body. The images can then be used to make 3-D images that are useful to doctors in viewing internal injuries or other types of trauma. It can also be used to visualize the brain or problems in your blood vessels.
There is no epidemiologic data directly relating CT scanning to cancer deaths, so scientific assessment must instead rely on the relationship between radiation exposure and death rates from Japanese atomic bomb survivors.
Dr. Bluemke acknowledged while the legitimacy of this approach remains debated, radiologists as well as clinicians may rightfully be confused by the ongoing controversy.
“Patients seeking medical help may legitimately question the rationale of, and any risks from, diagnostic radiology tests," Dr. Bluemke said.
NIH Clinical Center’s radiology and nuclear medicine has developed a radiation reporting policy in cooperation with major equipment vendors, beginning with exposures from CT and Positron Emission Tomography or PET scans.
PET scans detects the metabolic signal of actively growing cancer cells in the body. When CT is used in combination, oncologists are provided with a detailed picture of the internal anatomy that reveals the location, size and shape of abnormal cancerous growths.
All vendors who currently sell imaging equipment to Radiology and Imaging Sciences at the NIH Clinical Center will be required to provide a routine means for radiation dose exposure to be recorded in the medical record. This requirement will allow cataloging of radiation exposures from these medical tests, Dr. Bluemke said.
“The accumulation of medical testing doses of hundreds of thousands of individuals in the United States over many years will ultimately be necessary. We are encouraged because if the manufacturers do this for one institution, they simply use the same software for any institution,” Dr. Bluemke said.
The NIH will also require that vendors ensure that radiation exposure can be tracked by the patient in their own electronic personal health record, a move consistent with the American College of Radiology's and Radiological Society of North America's recommendations.
Dr. Bluemke said while the NIH’s new reporting policy is a step in the right direction, there are still important details to work out.
"The current reporting requirements are not sufficient to allow for the assessment of cancer risk from low-dose radiation in the general population, but they are nonetheless necessary to begin a data set to make this determination in the future." he said.
Within the next few months, software should be available for patients to maintain their own electronic medical records, so even if the radiation reporting system isn’t adopted industry-wide, patients can ensure their own records of such medical procedures are kept for future reference.
“We are waiting for issues regarding the national electronic medical record to be resolved, such as the standardization of information. That will be more complicated, but the Obama administration has now been devoting tremendous effort in this regard, and the VA system more or less represents a national method in this regard,” Dr. Bluemke said.
Lynette Summerill, is an award-winning journalist who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues, she writes a blog, Nonsmoking Nation, which follows global tobacco news and events.