Toshiba’s experts in high-tech medicine have created a powerful new CT scanning machine that they believe will save the lives of thousands of heart patients and stroke victims, if it survives the steely-eyed scrutiny of health insurers.

The new Aquilion One scanner (pictured at right) will cut costs while it saves lives, its advocates say, but they can’t prove it. At least not yet.
That’s a crucial omission, because the machine costs $2.5 million. Even previous-generation models such as the GE Light Speed scanners (pictured below) at Hoag Hospital in Newport Beach cost $1.3 million to $2 million.

The question of CT costs is a sensitive subject right now, because Medicare is fretting about escalating expenses for CT scans – and worrying about the radiation that CT scanners expose patients to. Medicare’s decisions about CT scans are doubly important, because private health insurers typically follow the lead of the government agency.

CT scans, or Computed Tomography scans, let doctors look quickly inside a patient’s body for signs of blocked arteries, stroke, cancer and other diseases. In the process, patients can be exposed to as much radiation as hundreds of X-ray exams.

Each year, Americans have more than about 62 million CT scans costing an estimated $500 to $1,000 each.

In December, Medicare threatened to stop paying for many such CT scans, saying it wasn’t convinced that using a CT machine to diagnose heart disease was “reasonable and necessary” except in cases such as patients experiencing chest pains.

After loud protests from doctors, medical societies and manufacturers, Medicare relaxed that position. In March, the agency agreed to keep paying for CT scans while medical researchers evaluate the diagnostic power of CT equipment.

The research will test whether CT scans are good enough to replace other costly procedures, such as inserting a catheter into a patient’s arteries so a doctor can see blockages.

“We need to prove it,” says Doug Ryan, senior director of the CT business unit at Toshiba American Medical Systems in Irvine. “But we wouldn’t put the Aquilion One on the market if we didn’t believe it would help patients.”

RADIATION

A CT scanner takes a series of X-rays of the patient’s body, then uses its computing power to piece them together into a composite picture of the patient’s insides. In an Aquilion One, the computer compiles data from 320 rows of X-ray sensors, so it’s termed a 320-slice CT scanner. That array is wide enough to capture the image of the entire heart between two heart beats.

In the process, a patient can receive about 15 millisieverts of radiation exposure – 100 to 500 times the amount of a chest X-ray.

Medicare estimates that the radiation from a single CT scan may increase a patient’s risk of cancer by 0.05 percent, or 1 chance in 2,000. That’s a slight addition to Americans’ lifetime average 20 percent risk, which is equivalent to 1 person in 5 diagnosed with a fatal form of cancer.

“This small increase in radiation-associated cancer risk for an individual can become a public health concern if large numbers of the population undergo increased numbers of CT screening procedures of uncertain benefit,” the agency said.

CT scans with “uncertain benefit” number about 20 million each year in the United States out of 62 million total, says biophysicist David Brenner of Columbia University.

In an article last fall in the New England Journal of Medicine, Brenner estimated that radiation from CT scans might be the cause of 1.5 percent to 2.0 percent of all cancers in the United States.

That estimate is disputed by Dr. Michael Brant-Zawadzki, former medical director for radiology at Hoag Hospital.

The basic reason for the disagreement: Scientists have not been able to determine whether very low doses of radiation are harmful, says Brant-Zawadzki, who is now Hoag’s executive director of neurosciences.

Everyone is subjected to background radiation, and it’s possible that below a certain threshold low-level exposures might cause no damage, he says. Low-dose radiation might even help protect against cancer, because the body responds to it by continually repairing its genes.

Estimates such as Brenner’s and Medicare’s are based on the plausible, but unproven, hypothesis that there is no threshold below which radiation doesn’t cause cancer-causing mutations, Brant-Zawadzki says.

“We should be cautious, but not alarmist, about radiation and CT scans,” he says.

After all, people aren’t fearful of background radiation, even at high altitudes where residents have less atmosphere above them to absorb cosmic radiation.

“Living for two years in Denver is like getting a basic routine diagnostic CT scan,” Brant-Zawadzki says.

COSTS

Toshiba has a prescription for cutting radiation exposure, following the same prescription it suggests for cutting costs by spending $2.5 million for its new CT scanner.

In each case, a hospital would install an Aquilion One and use it for gathering the information that’s currently collected through a series of common radiology tests.

For heart patients, Ryan says, the CT scanner would eliminate the need for a nuclear-medicine examination, which includes a radioactive tracer that’s injected into the blood stream. He says the new scanner would also let doctors omit a diagnostic cardiac catheter examination and accompanying angiogram, which involves additional radiation.

A typical battery of coronary tests costs $3,500 to $4,500, exposing the patient to about 42 millisieverts of radiation, Ryan says.

With an Aquilion One, the cost of the evaluation would be under $1,000 and the radiation exposure would be 15 millisieverts or less, he says.

That estimated saving of $2,500 to $3,500 per patient allows Toshiba to predict that a 300- to 400-bed hospital could recoup the price of buying an Aquilion One within five years by saving $3 million on diagnosing and treating cardiac and stroke patients.

Those savings – and the proposed changes in clinical procedures that they’re based on – are what Toshiba knows it needs to test and prove in the real world, not just on paper, if it is to realize its hopes for the Aquilion One.

The machine is already in use, or about to be installed, at six medical research centers ranging from Boston and Baltimore to Nevada, Ryan says. They will study its diagnostic prowess.

A similar study for earlier 64-slice CT scanners such as those at Hoag Hospital has already been completed and is awaiting publication in a peer-reviewed journal.

In an advance look at its findings, a Johns Hopkins University press release stated that, because of CT scanners, “as much as 25 percent of the 1.3 million cardiac catheterizations performed each year in the United States may be unnecessary.”

The issue of cost savings will be tackled in studies that Toshiba will underwrite at mainstream hospitals that install the Aquilion One after it goes into full commercial release in September, Ryan says.

The greatest dispute over CT scanners is whether it’s a good idea routinely to use them to screen symptom-free patients. That’s an increasingly common use of CT machines, but many doctors argue that the risk of repeatedradiation exposure outweighs the potential benefit of finding an undiscovered ailment.

For a patient suffering from chest pains, the risk calculation is much different. Medicare agrees that a CT scan in that situation is “reasonable and necessary.”

In that case, as Ryan puts it, “The risk of cancer is small compared to the risk of a wrong diagnosis.”

Related links:

• “Weighing the Costs of a CT Scan’s Look Inside the Heart,” New York Times (June 2008)
• CT Heart Scan Experts Criticize New York Times Article, from Angioplasty.org, an informational Web site supported by medical device makers, including Toshiba.
• Medicare decision on cardiac CT scans (March 2008)
• Toshiba scanner promises quick diagnosis for heart attack, stroke, O.C. Register (January 2008)
• Proposed Medicare decision on cardiac CT scans (December 2007)
• “Computed Tomography - An increasing source of radiation exposure” by David Brenner and Eric Hall, New England Journal of Medicine, November 2007. (PDF file)

Photos above:

Top, Larry Dentice, general manager and senior vice president, Toshiba America Medical Systems, Inc., with his company’s $2.5 million Aquilion One CT scanner. Photo by H. Lorren Au Jr. / Orange County Register.

Next, cardiac images captured by Aquilion One.

Next, Hoag Hospital is adding a new CT scan imaging room to their radiology department. Here, staff member Joseph Lontoc demonstrates the General Electric 64 Slice Light Speed CT machine. Photo by Rose Palmisano / The Orange County Register

Next, image captured with Aquilion One CT scanner shows brain arteries (red) and veins (blue). Photo courtesy of Toshiba.

In bottom photo, the lung and its branching air passages are visible in an image captured by the Aquilion One. The lung is large enough that it requires more than one pass of the CT scanner to capture the image. Photo courtesy of Toshiba.

This post was revised July 15 to clarify Ryan’s description of cardiac catherization and angiograms.

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