iPhone Application Tracks Radiation Exposure, Risk

Mark Baerlocher, M.D.

Educating the public, residents and referring physicians about radiation exposure and associated risk took a step forward with the creation of the new iPhone application, Radiation Passport.

The concept first came to Mark Baerlocher, M.D., as a resident in his final year in the Radiology Residency Training Program at the University of Toronto. Dr. Baerlocher co-authored a 2007 study that found that 92 percent of 127 patients surveyed were not informed of the radiation risks associated with tests they were scheduled to receive and had false perceptions about the use of radiation and associated risks.

The study, “Perception of Radiation Exposure and Risk Among Patients, Medical Students and Referring Physicians at a Tertiary Care Community Hospital,” has yet to be published but was presented at the Society of Interventional Radiology’s 2008 annual meeting.

That research cited a 2007 New England Journal of Medicine study that estimates 1.5 to 2 percent of all cancers in the U.S. may be attributable to CT in the future if current usage rates continue. Other studies have shown that potentially up to one-third of CT scans are not “medically indicated,” said Dr. Baerlocher.

“A lot of patients who undergo procedures and exams aren’t educated on the risks,” he said. “I think that’s unfortunate, and I think that has to change.”

To that end, the National Institutes of Health (NIH) recently began requiring CT and PET/CT equipment purchased by its Clinical Center to routinely record radiation dose exposure in a patient’s hospital-based electronic health record (EHR).

Patients, Physicians Estimate Dose, Risk

Radiation Passport is designed to track radiation exposure and calculate cancer risk related to radiology exams and procedures as well as common background radiation. From left: a screenshot from Radiation Passport lists imaging exams and related procedures for a given patient, with associated radiation exposures (effective dose); shows estimated risk of cancer with a specific exam (in this example, a bone scan), specific to a patient of given age and gender; and estimates risks of cancer (all exposure - Background + Medical and separately for Medical only— total and fatal) associated with radiation exposure for a patient of specific age and gender with a specific entered list of exposures.

Teaming with his brother Adrian Baerlocher, a programmer at Tidal Pool Software in Victoria, British Columbia, Dr. Baerlocher created Radiation Passport, a program designed to track radiation exposure and calculate cancer risk related to radiology exams and procedures as well as common background radiation.

He began by examining other research including the Biological Effects of Ionizing Radiation (BEIR) VII Committee’s 2005 lifetime risk model which predicts that approximately one in 100 persons would be expected to develop cancer (solid cancer or leukemia) from a dose of 100 mSv while approximately 42 of those 100 people would be expected to develop solid cancer or leukemia from other causes. Roughly half of these cancers would result in death, according to the report.

“We followed the same models that the BEIR VII Committee followed with the linear nonthreshold model,” Dr. Baerlocher said. “From that report I came to the conclusion—which I’m sure many other people share—that more education and radiation risk awareness is necessary. The next logical step was to team up with my brother to program the iPhone application.”

Functions of the downloadable application, which costs $3.99, are tailored to the user. If a specific exam is ordered, the patient can enter demographic information and exam type and the program will provide the estimated radiation does and estimated cancer risk from that exam. Patients can also track their radiation exposure throughout their lifetime. As of early November, about 700 applications had been sold, Dr. Baerlocher said.

Healthcare workers can also use the program as an educational tool and resource in helping to evaluate the risk-benefit equation when deciding if an exam is necessary

“A clinician can enter in the patient’s gender and age, the modality of the exam and the body part targeted in the exam or procedure and the program assigns an average, published radiation effective dose,” Dr. Baerlocher said. “The program then provides an estimated risk of developing fatal and nonfatal cancers from that dose due to that specific exam and the patient’s age and gender.”

Critics Say Patients Need the Full Story

Some physicians say they want to make sure patients are getting all of the information when it comes to radiation dosage.

"My view is that no matter how exactly we believe we can measure something, those measurements should be considered estimates of the item of interest’s true value,” said James R. Duncan, M.D., Ph.D., an associate professor of radiology in the Interventional Radiology Section of the Mallinckrodt Institute of Radiology at Washington University School of Medicine in St. Louis and a member RSNA’s Quality Improvement Committee and the structured reporting subcommittee of the RSNA Radiology Informatics Committee. “While it is unnerving to think we are relying on estimates rather than true values when making decisions, the alternative is to completely discard the available data and rely on emotion to drive decisions.”

Dr. Baerlocher points out that there are inaccuracies with any model. “It is the best information we have available at this time, and in medicine that’s exactly what we do,” he said. “We act based on the best information we have at the time.”

Other physicians point out that the application only provides the risk side of the equation, making patients more likely to refuse a particular exam without having all the information. But Dr. Baerlocher said that healthcare workers have a responsibility to inform patients of the benefits of the exam as well as the risk.

“In the future I wouldn’t be surprised—and I kind of hope—that exposure doses will be attached to each individual imaging examining procedure so that it would be part of the patient’s EHR,” he said.

NIH Requires Dose Tracking

The NIH decision to require CT and PET/CT equipment purchased by its Clinical Center to routinely record radiation dose exposure in a patient’s hospital-based EHR is a significant step in that direction. About 25,000 CT and 1,250 PET/CT scans are performed at the center each year as part of NIH research protocols.

“Any new radiation producing equipment that we purchase at NIH will have this requirement,” said David Bluemke, M.D., Ph.D., director of radiology and imaging sciences at the Clinical Center. “In addition, the manufacturers are to provide a means for patients to upload radiation doses to their personal electronic medical records, such as Google Health or Microsoft HealthVault.

"This is necessary not only at NIH, but also at all hospitals across the country,” said Dr. Bluemke. “There is currently no routine means for any person in the U.S. to determine their annual lifetime exposure to medical radiation. Our policy is only one step in that direction.”

Bridging the Gap Between Patient, Physician Knowledge

Patients aren’t alone in their lack of radiation knowledge, according to Dr. Baerlocher’s 2007 study. Dr. Baerlocher and colleagues surveyed medical students and referring physicians from various specialties to determine knowledge on radiation exposure and risk associated with commonly ordered medical imaging tests. Thirty-two referring physicians and 30 medical students completed the survey.

Researchers found that 25 percent of physicians and 43 percent of medical students were unaware that interventional procedures utilized ionizing radiation. Nine percent of physicians were unaware that CT scans were associated with ionizing radiation.

"In terms of the medical community as a whole, their education in radiology is poor and their education on the radiation side of radiology is probably non-existent,” said Andy Myers, M.D., C.M., a radiologist in the Department of Radiology at Lakeridge Health Corporation in Oshawa, Ontario, and co-author of the study. “We’re trying to bridge the gap between our knowledge and the public’s knowledge. It’s an ongoing challenge.”