Over a third of clinicians have received no formal education on the risks of exposure to ionizing radiation from imaging examinations, and more than a quarter believe the impact of dose on lifetime cancer risk is either very small or negligible, a new U.K. survey has found.
The study, presented at the recent Annual Scientific Meeting of the U.K. Royal College of Radiologists (RCR) in Liverpool, adds to a growing body of international evidence reporting a tendency for hospital doctors to underestimate the future health risks of CT scans, said Dr. Ben Young and colleagues from the Derby Teaching Hospitals National Health Service (NHS) Foundation Trust.
"Hospital doctors should receive regular mandatory education on the long-term risks of patient exposure to CT scans," they noted. "This could promote consideration of alternative diagnostic strategies that avoid exposure to ionizing radiation when possible."
The team's goal was to measure doctors' knowledge of associated risks of exposure to CT scans and other imaging procedures in a busy teaching hospital in England. Clinicians at the Royal Derby Hospital completed an anonymous online, multiple-choice survey about their education and knowledge of the risks involved with exposure to ionizing radiation.
Of the 647 doctors contacted between October and December 2016, 170 (26%) responded. Nearly half (46%) of respondents were consultants/senior doctors, while F1 to F2 grades, ST1 to ST3, and training grade ST3+ each accounted for 16% of the sample. Their medical specialties are shown in the following chart.
Medical specialties.Nearly two-thirds of respondents (65%) had received formal education on the risks of exposure to radiation. Almost all of them said they were aware that CT scans (98%) and chest x-rays (97%) involve ionizing radiation. Also, the majority of respondents identified that isotope bone scans (84%) and PET scans (81%) involve radiation, but some of them thought that MRI exams (8%) and ultrasound scans (4%) deliver radiation.
Exams that involve ionizing radiation.Lifetime cancer risk associated with a chest, abdominal, and pelvic CT scan for a 20-year-old female patient was identified as approximately 1 in 30 (5%), 1 in 300 (the optimal response -- 22%), and 1 in 3,000 (46%). The proportion underestimating the risk as being either 1 in 30,000 or negligible was 27%.
Average impact of a chest, abdomen, pelvis CT scan.The survey was conducted as part of a behavioral study to reduce demand for common diagnostic tests, and it was funded by the Health Foundation, an independent U.K. charity committed to bringing about better health and health care for people.
Overall, the number of CT scans performed in NHS hospitals in England increased from 1.7 million in 1995 to 1996 to 5.2 million in 2013 to 2014, and demand for CT scans can vary by geographic region and between referring doctors, suggesting a proportion may be avoidable, Young and his colleagues explained.
"The primary associated potential harm of CT scans is the risk of cancer from ionizing radiation, with greater susceptibility to harm in female and younger aged patients," they continued. "U.K. regulations and professional guidelines dictate that patients must be protected from unnecessary exposure to radiation. This requires high levels of practitioner knowledge of the procedures that involve radiation and the associated risks."
Understanding awareness of the risk of exposure to CT scans on future health among doctors is important as alternative safer options might be overlooked, they added.
Looking to the future, the authors now plan to conduct follow-up surveys to monitor whether their behavioural and educational interventions improve doctors’ awareness of radiation risk. It will be important to see whether the work has an impact on awareness and usage of tests, they concluded.
There is more information and updates about the wider project on the website: http://www.awarenessproject.net.
