Somatom Definition AS,
Siemens Healthcare

Special report: CT "dose wars" heat up

January 26, 2011

by Olga Deshchenko, DOTmed News Reporter

This report originally appeared in the January 2011 issue of DOTmed Business News

A computed tomography scan at Wake Radiology, a practice with offices throughout the so-called research triangle region of North Carolina, might only take a few minutes, but it leaves a permanent record in a fast-growing database.

“About two years ago, we started keeping track of every single, individual scan dose,” says Dr. Thomas Presson, a radiologist with the practice.
The database allows radiologists to identify inconsistencies or significant variations in dose across all of the practice’s CT scanners. If a dose for a certain type of scan on a specific CT is found to be creeping up over time, it indicates an employee should say something during the equipment maintenance process, not an alert on the system.

Today, Presson says patients are asking questions about radiation dose on a more frequent basis, both before and after their CT scans. “Sometimes, they’ve had three or four scans and they wonder if it impacts their risk for cancer,” he says.

Patient worries should come as no surprise. CT imaging has had some public relations troubles of late. Over the past few years, many patients have read about victims irradiated by wrongly programmed scanners at a Los Angeles hospital and the explosive growth of Americans’ exposure to medical radiation.

In fact, although CT imaging only accounts for between 11-13 percent of all radiologic exams, it’s likely responsible for nearly two-thirds of the public’s medical radiation exposure, according to studies published in the American Journal of Roentgenology. Some scientists even speculate that CT scans taken in 2007 alone will ends up producing tens of thousands of future cancers.

While those numbers are hotly disputed, and even the link between relatively low levels of medical radiation generated by CT imaging and cancer is not entirely explained, the public is understandably growing warier. No one wants to be exposed to a procedure that’s meant to find cancer while also contributing to the likelihood of being afflicted with the disease.

Consequently, for radiologists looking to purchase new machines or upgrade existing systems, dose management is becoming a major selling point. “We’ve definitely seen an uptick in terms of dose reduction climbing the decision tree,” says Kirk Ising, author of a recently released CT report and senior research analyst for KLAS Research.

Manufacturers have made note of that uptick and are acting accordingly --- nearly every CT vendor now offers some type of dose reduction hardware or software. “It’s hard to overstate how important dose reduction is in terms of everything that manufacturers are doing now,” says Mark Silverman, CT marketing manager with Hitachi Medical Systems America Inc.

But dose reduction isn’t just the province of manufacturers -- radiologists and even third-party service companies are all trying new strategies to keep image quality high and ionizing radiation exposure low.

The tech approach to lower dose
Most of the biggest CT makers have already moved into developing dose-lowering technology, largely through a suite of software algorithms that clean up noise so lower dosages can be used during scans.

GE's LightSpeed VCT
XTe with ASiR

The technique is called adaptive statistical iterative reconstruction. It’s essentially a computationally faster version of reconstruction tools that have long been used in PET imaging, and that are thought to provide better signal-noise-ratio than filtered back projection, the usual CT technique.

Each vendor has its own twist on the technology. For instance, almost two years ago, GE Healthcare unveiled its ASiR module, which the company claims can cut dosage by 40 to 50 percent for its LightSpeed VCT systems.

Philips Ingenuity CT

And late last year, Philips Healthcare said one if its newest CT scanners, the Ingenuity CT, will include iDose4, the latest iterative reconstruction technique from the vendor. This feature lets users toggle between low dosage and improved resolution, letting them dial down dosage by up to 80 percent.

Philips’ intention with iDose4 is to move the low dose capability from a mode to a standard, as some radiologists don’t always use the tools that are available on their systems. “It’s like having a fuel economy button on a car that you never switch on,” says Dominic Smith, vice president of marketing, clinical science, CT and nuclear medicine with Philips. “What’s the point?”

And Toshiba America Medical Systems Inc., which has offered dose reduction features on its CT scanners since at least the mid-1990s, just got U.S. Food and Drug Administration clearance for AIDR (Adaptive Iterative Dose Reduction), its version of the latest dose reduction technology.

The company says the technology cuts dose by up to 75 percent, when compared against not having any dose-reduction software.

News of the FDA clearance came the week before the technology was shown at the Radiological Society of North America’s annual meeting at the end of November.
“Christmas came early for Toshiba from the FDA,” says Joe Cooper, director of Toshiba’s CT business unit.

But even as AIDR-based systems start rolling out, next generation technologies can already be glimpsed on the horizon. Only a few months ago, at RSNA, GE Healthcare unveiled its new model-based iterative reconstruction technology called Veo. This technology, whose processing hardware is housed in a hefty black box, is thought to be an even more powerful noise-canceling technique.

“This is taking it to a different stratosphere,” says Nilesh Shah, global marketing officer for the company’s CT business. Veo is currently available in Europe and pending FDA’s OK in the United States.

Of course, not all dose-reduction technology is based on advanced algorithms. Siemens Healthcare, which has developed its own dose-cutting software, IRIS (iterative reconstruction in image space), is also creating software that can help operators by suggesting settings to lower dose. The technology, part of the Fast Care platform, will be available on the company’s Somatom Definition AS scanners in April 2011 and the Somatom Definition Flash scanners in June 2011, said Jakub Machon, Siemens’ product marketing manager for CT in an e-mail to DOTmed News.

The industry is also looking to some cooperative initiatives. Most manufacturers are currently in the process of incorporating additional safety features into their CT systems, as part of trade group Medical Imaging & Technology Alliance’s CT Dose Check Initiative outlined last year. Among the additions is a new alert setting, which will notify operators when recommended dose levels are exceeded.

Such radiation dose safeguards will be added to all CTs, regardless of the brand name on the scanner. “I think what really is encouraging is the commitment of the industry as a whole, putting the competitive pieces aside, to building as many safety features into our scanners as we can and working together with all the stakeholders to do what’s necessary to help,” says Ken Denison, global CT dose leader for GE.

Looking beyond technology
Even though technology plays a major role in lowering CT dose, vendors and end-users recognize much of the responsibility lies with medical professionals – radiation physicists, radiologists, equipment operators and even the referring physicians. “It’s not just what features we manufacturers put into the machine,” says Hitachi’s Silverman. “There are a lot of stakeholders here with lowering dose.”

Vendors are working to raise providers’ familiarity with the equipment and its dose lowering capabilities. For instance, GE Healthcare said it was looking to provide more training through free online courses and dose seminars across the country. And last year, Siemens convened a panel of 15 CT experts in the fields of radiology, cardiology and physics, to figure out how OEMs can develop and improve dose reduction technologies.

The panel’s first recommendation is simple: start using the dose reduction tools that are already available. “There’s a difference between talking about things and doing things,” says panelist Dr. Elliot Fishman, a professor of radiology, oncology and surgery with Johns Hopkins University. “Who’s going to be against low dose radiation? The question is: How do you implement that in practice?”

The expert panelists are also working on sharing protocols and best practices within their medical facilities. “If something goes well in one institution, and you get a really good dose and a really good study, there’s no reason for everyone to reinvent the wheel,” says Fishman.

Even some third-party service providers are now offering equipment training in their contracts. One company, Shared Imaging, incorporates education in its CT rent and lease programs, because doses can be “dramatically reduced just by educating and training the staff of the hospital,” says Ray Stachowiak, the company’s president.

The challenge of tracking
Technology and training are essential to lowering dose, but so is actually tracking a patient’s lifetime exposure. “It’s very hard to improve what you can’t measure,” notes GE’s Denison.

That’s why in addition to its database for tracking dose throughout the practice, Wake Radiology imaging professionals set up a system in its partner hospitals that enables emergency department physicians to see the number of CT scans a patient has received when they arrive. “It searches the patient record,” says Presson. “If they had five CTs in two years, their name will get a little icon next to it.”

This way, physicians can make more informed decisions about using a CT scanner on a specific patient. But this practice is confined to Wake Radiology’s database. While vendors are introducing dose-reduction technologies, the need for solutions that automate dose monitoring and reporting and crosses hospital database borders persists. “There’s a hole in that area,” says Presson.

“It’s a tough niche to fill because every hospital system has its own health record system. I’m not aware of any that have a very good radiation dose tracking system. Our hospital systems have electronic health records but they don’t really have a system to [track radiation dose],” he says.

Providers who were contacted for KLAS’ CT report also cited the need for dose monitoring solutions. Part of the problem with tracking, says Ising, is that no standards on what or how measurements should be tracked have been established.
According to the KLAS report, as the first vendor to develop tools that “allow CT clients to automatically track and report dose numbers on exams,” Siemens is currently considered to be the leading company in offering radiation dose tracking capabilities.

But undoubtedly more vendors will offer these solutions – right before heading to the next battleground.

“I think the slice wars have moved into dose wars and dose wars themselves are moving into the image quality and quantification wars of the future,” says Philips’ Smith.