But if the scan must be done, today's scanners and their software can alter dose parameters, and many systems offer post-processing and filters that require less radiation.

"There are several different ways to lower dose," says Young. "One way is to actually lower the amount of radiation coming out of the system. We can do that with what's called tube modulation...another approach is making the image better by reducing noise in the image."


Most new models feature sophisticated software like GE's ASIR, Siemens' IRIS and Philips' iDose software, and Toshiba has something called Quantum Denoising Software (QDS), that allow radiologists to significantly reduce radiation dose - up to about 80 percent reduction in some cases. The speed of a given scan can play a major role.

"For a coronary CT examination on any single-source CT scanner - and it doesn't matter if it's a 320, 256 or 64-slice - scanning the heart itself takes about 3 to 20 seconds, depending on the scanner," says Gungor. "To give you just a quick idea of background radiation, if you go outside and stand and look around, you'll be collecting about 3 mSv of dose per year, depending on where you live. That's the average background radiation. So a coronary CT examination on a conventional single source CT technology is about 5 to 20 mSv. With the Flash technology, the heart can be scanned in a quarter of a second. You need only 250 milliseconds to scan the heart and thus your dose level drops dramatically to about .8 or .9 mSv, depending on the patient."

It's not only about lowering radiation dose, but the amount of contrast media necessary to perform a given scan. Certain contrast media have been associated with kidney complications. Most of the major manufacturers have designed software and applications geared toward lowering contrast media dose.

Even in the refurbished market, independent sales and service companies are starting to provide radiation-dose reduction systems for refurbished scanners.

"There has been a lot of concern over dosage which in turn causes people to be concerned about the quality of what they buy," says Kramer. C&G has been offering an FDA-approved dose-reduction software that reduces radiation dose up to 50 percent using a workstation that applies specialized algorithms and image filtering to lower the dose. The company also offers extended warranties on X-ray tubes, but ironically these options haven't been flying off the shelf because of the added expense.

"Nobody wants to pay for it," says Kramer. "You would think with all the recent activity going on, with lawsuits and people getting exposed [to harmful levels radiation from CT systems], you would think more people would be interested, but they aren't buying."

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