March 2015

Guest Commentary: Radiation Dose — Properly Balance Risk, Reward for Dose Optimization
By Dominic Siewko
Radiology Today
Vol. 16 No. 3 P. 25

Radiation dose from diagnostic procedures has become a topic of debate throughout the medical industry and in the lay press. Starting in 2016, the Centers for Medicare & Medicaid Services will reduce reimbursement by 5% for CT scans that are not acquired using dose optimization specifications published by the National Electrical Manufacturers Association's Medical Imaging & Technology Alliance. Health care providers' and manufacturers' economic incentive, along with their responsibility, protect both patients and clinicians. There is still confusion in the market about radiation dose management in diagnostic scans. As a health physicist, I feel compelled to set the record straight on the real risk and reward of radiation dose.

The Benefit Is Clear
In the United States, the use of CT nearly tripled between 1996 and 2010, from 52 scans per 1,000 patients to 149 scans per 1,000 patients. According to the ACR, nearly 68 million CT scans are performed annually. Put another way, nearly one in every five Americans will receive a CT scan this year. The reason is simple: CT scans can yield a better, more precise image than a standard X-ray, and can eliminate the need for exploratory surgery in some cases. That's the benefit part of the equation.

What's the Risk?
Radiation dose is the other side of the equation. With CT scans, technologists can limit their exposure by stepping out of the room or behind a barrier during the procedure. Patients, as the subjects of the procedure, receive the exposure. While a CT scan adds to our patients' dose burden, the amount of background radiation we're all exposed to in a year is actually higher on average than some diagnostic CT scans. Consider that the average background, radiation dose per person in the United States is 3 mSv per year. Compare that with a typical head CT scan dose of 2 mSv. A roundtrip flight from New York to Tokyo is approximately 0.15 mSv compare with an average CT extremity scan dose of 0.1 mSv.

Balancing Exposure
In that context, how are patients supposed to be informed about the right dose for them? And perhaps more importantly, what's the best way for health care providers to both protect and inform people?

The overall goal is to provide clinicians with the best possible diagnostic information at the lowest possible dose. There are a number of ways to strike a balance between dose and benefit.

1. Justify each procedure. Traditional protocols, driven by volume-based reimbursement models, typically call for the simpler, lower dose X-ray first, then a CT scan, then an MRI—or some variation on that theme. But the truth is, it may make more sense to start with a CT scan, sparing the radiation exposure (not to mention both the time and expense) of the X-ray or other preliminary scan, and reach a definitive diagnosis sooner.

2. Optimize each procedure. Clinicians need to demand the technology and training that allows them to enhance and adjust images obtained at lower doses. This produces the diagnostic benefit while limiting the dose.

3. Normalize protocols. Existing patient exam data with regard to radiation exposure is currently underutilized. Understanding the variability among scanners in one department is a good first step to ensuring that appropriate, consistent radiation doses are delivered.

Like most things in life, diagnostic radiology is enhanced when the balance is found between the diagnostic benefits and the dose required to get there. Striking that balance is becoming easier through a combination of evidence, technology, and intelligence. I have faith that further advancements will continue. And as they do, patients and clinicians should continue to keep the real risk and rewards in mind, as well as these approaches to achieving them.

— Dominic Siewko is a former radiation safety officer and the current clinical marketing manager for Philips Healthcare's DoseWise product line.