In the world of medicine, imaging technology drives diagnosis and treatment. Since the advent of the first CT (computerized tomography) scan, new devices have been measured by the triple mantra of (1) image resolution, (2) speed of image capture and (3) lowering of radiation exposure necessary for the image. The quest to stay on top of the game is not unlike that in the computer world where faster, smaller processors do more things with less power. New generations of super scanners are producing dramatic new images that are changing the view of our “internal world”.
Phillips recently announced a new 256 slice, high speed scanner that can give a patient a full body scan in less than a minute — and exposes them to 80 per cent less radiation than a traditional X-ray machine. The machine scans the body as well as rotating around it, sending out 256 pulses every one-third of a second. It is so powerful that it can capture an unblurred image of an entire heart in less than two heartbeats. The $2-million Brilliance CT machine can capture the body’s skeleton, organs and blood vessels in minute detail. The new system produces superior cardiac images as its speed and coverage freezes the motion of the heart and produces a clear snapshot of the coronary arteries.
But its benefits extend beyond cardiac and cardiovascular scanning. MetroHealth in Cleveland, Ohio, deployed Philips Healthcare Brilliance CT scanner in October 2007. They can use it to complete a kidney stone protocol on an uncooperative patient writhing in tremendous pain. The four-second scan gives high-resolution diagnostic images for everything from trauma scans to routine chest, abdomen and pelvis protocols as well. They are using the scanner for both routine imaging and emerging applications such as brain perfusion and cardiovascular imaging.
Not to be outdone, Toshiba currently has a machine that dominates on slice count with its AquilionONE 320-slice scanner (most CT scanners in your neighborhood hospital are 16 slice scanners, and the ‘high resolution’ ones currently in larger institutions are mostly 64 slice scanners). Brigham and Women’s Hospital in Boston is an early adopter of Toshiba’s AquilionONE CT scanner (click on this link then Select ‘Clinical images’ to see sample scans). “The new system enables dynamic volume imaging,” Frank Rybicki, MD, PhD, director of cardiac CT and vascular CT/ MRI has been quoted as saying. “This provides vastly more information for stroke evaluation than current CT scanners,” states Rybicki, who predicts that after the clinical evidence is in, every stroke center will consider an investment in such a scanner. Click here for link and then click on ‘display images’.
More slices means they can ‘see’ smaller things in higher resolution. However, one should realize that current-generation 16-slice scanners, the workhorses of most hospital x-ray departments, are more than adequate for nearly all routine clinical applications in body imaging, including pulmonary embolism detection and full-body trauma scans, so higher resolution isn’t always necessary, depending on what you are looking for.
Some believe the field needs to move away from rigid slice numbers and speed as the sole determinant of a CT scanner’s power and utility and consider factors such as overall versatility and usefulness of a system. At the Medical University of South Carolina (MUSC) in Charleston, S.C., one of the new generation of Siemens Somatom Definition AS (adaptive scanning) imaging systems is being evaluated.
CT scanners will likely play a key role in facilitating new treatment techniques such as radiofrequency ablation, cryoablation, targeted chemotherapy and brachytherapy. These minimally invasive therapies require image guidance, and scanners like the Definition AS offers the speed and resolution necessary to enable them, and are adaptable to a wider range of imaging requirements.
Yet another contestant is General Electric, where CT meets High Definition. The newest generation is GE’s modified LightSpeed VCT scanner. HDCT enables dual-energy imaging and improved x-ray conversion speed combined with improved software reconstruction. Because it produces very sharp images of the coronary arteries and abdominal visceral arteries the scanner tackles one of the primary problems in coronary imaging. It subtracts out coronary calcium in arterial images. Calcium can obscure diagnosis in cardiac cases, so the ability to subtract it should improve diagnostic capabilities. If the system meets its full potential, it could reduce the need for invasive cardiac catheterization. Other potential clinical applications include accurate software auto-bone removal in 3D scans. (Click on image below then click on Images from the GE Lightspeed VCT)
Dual-energy CT may improve body imaging as well as providing increased sensitivity with less contrast media. One of the new GE scanners is at the Medical College of Wisconsin in Milwaukee, WI. At the present time they are scheduled for FDA approval in mid-2008. Click here for a video made with the GE scanner.
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