The EBCT scan that we use at OC Vital Imaging delivers the lowest dose of radiation for any type of exam when compared to Multi Detector CT (MDCT) scans, including the newest “64 slice” CT scans. It is extremely important that any screening test be safe and accurate. The EBCT meets both of those criteria. Recent newspaper articles quoted that the radiation dose for a full body scan performed on a conventional CT scan (MDCT scan) was equivalent to the radiation exposure received by survivors of the atomic bomb. The EBCT scan delivers 1/5 to 1/10 the dose of radiation.

The best way to compare radiation doses is to compare the dose to commonly used tests. The radiation dose that you receive if you live in Denver, Colorado  for three months is equivalent to three chest X-rays or one set of conventional dental X-rays (higher elevations expose you to higher natural radiation from the atmosphere).

The chart below compares the radiation dose for various exams performed on our EBCT scan compared to the radiation dose delivered on a conventional CT scan (MDCT scan). You can easily see the huge safety factor in using EBCT scans. If you choose to have you heart scan or full body scan performed at an imaging center other than OC Vital Imaging, you need to make sure that it is an EBCT scanner and not a conventional or MDCT scanner. Only EBCT scanners can provide the lowest radiation dose with the highest accuracy in detecting coronary calcium.


Radiation concerns with 64 slice CT scan

However, along with the promise, the technology raises concerns, including the amount of radiation the machines emit.

Cardiac catheterization also exposes patients to radiation because of the use of a type of moving X-ray known as fluoroscopy.

With 64-slice CT, the radiation can be more than twice that amount, roughly the equivalent of 100 to 300 chest X-rays, said Cynthia McCollough, an associate professor of radiologic physics at the Mayo Clinic.

Such a dose probably only raises a person's cancer risk by only one-tenth of 1%, she said.

However, because the technology is quick and non- invasive, there may be a temptation to do repeated scans.

"That's my fear, too," McCollough said. "This is not something people should be getting every year."

The other concern about 64-slice CT is who will control it.

Traditionally, cardiologists have presided over the realm of heart disease. Now, radiologists are likely to have an integral role.

In many hospitals, it is likely the two specialties will work together.

But it is possible that radiologists could set up stand-alone facilities with 64-slice machines and get referrals directly from family doctors, bypassing cardiologists altogether. Such facilities could even take walk-in clients without a referral from a family physician.

Cardiologist Wann, of the Wisconsin Heart Hospital, said people in both specialties want to do what is right for the patient. And areas both need each other's expertise.

If radiologists try to eliminate cardiologists, "The first time they screw up, they'll never have another (patient)," he said.

Beyond that, the question is, will the technology live up to its hype?

"Every time I hear it's 'the answer,' I've been lied to," Wann said.

"I expect it to better with the 64 (slice). It will be an incremental improvement in our ability to diagnose coronary disease."


Appeared in the Milwaukee Journal Sentinel on Jan. 16, 2006.