As imaging technology advances and medical devices improve, healthcare professionals are more inclined to use these state-of-the art scanners to look inside patients’ bodies. Computed tomography usage, for example, more than tripled between 1996 and 2010. Over the same period, MRI (magnetic resonance imaging) usage increased fourfold. It is not surprising, therefore, that patient radiation exposure has also risen.
An article in JAMA, published today, asks the question to see if this technological dependance is going too far or even putting patients in danger with too many scans. Some people are worried about raditation from mobile phones, so stepping inside a multi-million dollar machine that blasts the body with one type of electromagnetic resonance or another, is going to draw warranted safety questions.
Rebecca Smith-Bindman, M.D., of the University of California, San Francisco, and colleagues set up a study to better understand the trends in imaging utilization and associated radiation.
They sifted through the electronic records from six large integrated health systems covering different regions of the United States, allowing them to create an estimation of radiation exposure from selected tests.
Gathering data from approximately 1-2 million member-patients each year from 1996 to 2010, the researchers found a total of 30.9 million imaging examinations during the study period, giving them an average of 1.18 tests per person per year, of which 35 percent involved advanced diagnostic imaging (i.e., CT, MRI, nuclear medicine, and ultrasound).
The authors go on to say:
“Increase in imaging use over this period was likely driven by many factors, including improvements in the technology that have led to expansion of clinical applications, patient- and physician-generated demand, defensive medical practices, and medical uncertainly – all factors that would be expected to influence utilization across all systems of medical care.”
One of the main points made in the article is that there has never been a comprehensive study of how much use healthcare providers are making of imaging technology. The studies that have been done are usually based around private practices and done for insurance purposes, and in these cases, imaging is usually encouraged. Looking at a wider range of patients and facilities enables the authors to provide us with a clear picture.
The authors summarize the use of various imaging techniques:
- Radiography and angiography/fluoroscopy rates were relatively stable over time: radiography increased 1.2 percent per year, and angiography/fluoroscopy decreased 1.3 percent per year.
- Computed tomography examinations tripled (52/1000 enrollees in 1996 to 149/1000 in 2010, 7.8 percent annual growth)
- MRIs quadrupled (17/1000 to 65/1000,10 percent annual growth)
- Ultrasounds approximately doubled over the same period (134/1000 to 230/1000, 3.9 percent annual growth)
- Nuclear medicine rates decreased (32/1000 to 21/1000, 3 percent annual decline), although after 2004, PET imaging rates increased from 0.24 per 1,000 enrollees to 3.6 per 1,000 enrollees, 57 percent annual growth
- The increase in the utilization of CT was associated with an increase in estimated exposure to radiation, with the average per capita effective dose increasing from 1.2 mSv in 1996 to 2.3 mSv in 2010.
- The percent of enrollees who received high (> 20-30 mSv) or very high (> 50 mSv) radiation exposure during a given year also approximately doubled across study years.
- The researchers also estimated that by 2010, 2.5 percent of enrollees received a high annual dose of greater than 20 to 50 mSv, and 1.4 percent received a very high annual dose of greater than 50 mSv.
- By 2010, 6.8 percent of patients who underwent imaging received a high dose of more than 20 to 50 mSv and 3.9 percent of patients received a very high dose above 50 mSv during this single year.
The authors conclude their study by presenting the point: that while healthcare has obviously improved with the use of technology, given the high costs of imaging, some $100 Billion annually, combined with the cancer risks and other possible side effects, the benefits of sending patients for scans, should be balanced by weighing the medical needs against both financial and heath risks of the technology itself.
Written by Rupert Shepherd