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Diagnostic Imaging

Canadian hospitals buy 64-slice CTs

Siemens Canada has sold four of its new 64-slice CT machines to Canadian hospitals - two of them to the William Osler Health Centre in Brampton, Ont., and another two to the Niagara Health System, based in Niagara Falls, Ont.
The "Somatom Sensation 64" machine, announced by Siemens at the end of 2003, is said to be the only Computed Tomography scanner on the market capable of acquiring 64 slices per gantry rotation. Most hospitals are using two-, four- or in advanced cases, 16-slice CT scanners.

The devices sell for approximately $2 million each, but are said to dramatically reduce the time needed to complete patient exams while simultaneously collecting more detailed anatomical information. "The key return for the hospital is increased patient throughput," said Andy Hind, vice president of the Medical Solutions Group at Mississauga, Ont.-based Siemens Canada Ltd.

As such, the high-powered CTs are seen as a solution to the backlog of patients in Canada awaiting diagnostic imaging exams.
Hind noted the machine performs a complete cardiac study in 15 seconds. "You can do a 24-phase cardiac study in a single breath-hold," he said, pointing out that it's especially useful for elderly patients - who have trouble holding their breath for long - and pediatric patients, who can only sit still for short while.

The images captured are said to be much sharper than before, with fewer artifacts, due to the faster speed of the system.

With the large data sets collected by the machine, 3D and 4D (3D plus motion) imaging is improved. Moreover, image reconstructions begin as the exam is under way -- a technological achievement of the 3D software. "It does reconstruction on the fly, eliminating manual work afterwards by the radiologists," said Hind.

The 3D images may also prove to be useful to other clinicians, such as surgeons conducting pre-operative planning or for consultation during surgical operations.
Another significant feature: the system automatically gauges the amount of radiation needed to adequately image various parts of the body, thereby reducing the x-ray dosage during an exam by up to 66 percent compared with traditional CT systems.

The high-speed gantry rotation and image acquisition is made possible largely through a new x-ray tube design, which makes use of an oil-cooled technology rather than air cooling. "It's a paradigm shift in x-ray tube design," said Hind. "Heat is drawn away much more effectively."

He explained that in more conventional CT systems, radiologists and technologists must often wait for the tube to cool down after conducting a few exams, thereby slowing down the flow of patients through the CT suite. "By eliminating tube heat as a bottleneck, we've also improved workflow in the radiology department," commented Hind.