The discovery of ultra-low dose computed tomography (CT) scans will spark a slow-but-sure shift within radiology departments entirely away from traditional x-rays, according to a team of Vancouver Coastal Health Research Institute (VCHRI) radiologists leading groundbreaking CT research.
“The Emergence of Ultra-Low Dose Computed Tomography and the Impending Obsolescence of the Plain Radiograph?”, recently published in the Canadian Association of Radiologists Journal, details the researchers’* discovery of ultra-low dose CT scans using their own innovative scanning techniques and new Siemens technology. This is the first published paper highlighting that lower radiation doses are now possible with CT scans than conventional x-rays across many body parts.
“Once this technology becomes firmly established, as we expect it will over the next few years, any institution seeking new equipment will likely move towards CT” says Dr. Peter Munk, co-principal investigator and head of musculoskeletal imaging at Vancouver General Hospital (VGH).
“It is not going to be a wholesale change in an abrupt, short period of time. Over the next 20 years across radiology departments in the Western world, there will be a gradual but steady shift away from the inaccuracies of conventional radiography and toward ultra-low dose CT scanners for technology upgrades.”
Patients can also expect a very gradual introduction to ultra-low CTs, starting with groups who would benefit most from the lowered dosage, says Dr. Patrick McLaughlin, co-principal investigator and radiologist at VGH.
“CT has been shown to benefit heavy smokers in particular within the age group of about 35 to 65, and certain screening programs in the U.S. have shown a 20% reduction in mortality,” says Dr. McLaughlin. “Radiologists are almost certain that, in general, ultra-low dose CT is more appropriate than chest radiographs for detection of cancers in that population and also, for instance, in patients who are being followed up after surgical removal of lung cancer.”
“Other patient groups that traditionally undergo repeated CT scans such as those with urinary calculi may receive very large doses of radiation over their lifetime, limiting the frequency of CT examinations they could get,” he adds.
“Ultra-low dose CT scans change that paradigm; they can be delivered more often when required and can better monitor treatments.”
Radiation fears fuel quest for lower doses
In 2009 research suggesting that CT scans could be increasing the public’s burden of malignancy by 29,000 cases per year in the U.S. became very publicized by the media and fears around CT scans heightened.
“There was a reactionary massive research and development effort by industry and radiologists to counteract this — to reduce dosages while still benefitting patients and the population at large,” says Dr. McLaughlin.
Such fears over radiation may be allayed considering the natural background radiation people are exposed within their everyday environments, or even through their travels, in comparison to the new ultra-low CT doses.
“The difference between even just choosing to live in Vancouver versus Nelson is the equivalent of 30 ultra-low dose CT scans because Nelson’s higher soil radioactivity and altitude brings with it more radiation,” explains Dr. Hugue Ouellette, co-principal investigator and Chief Executive Officer of Vancouver Imaging.
“People fly all the time and a trans-Atlantic flight exposes someone to 0.1 millisievert (mSv) of radiation,” adds Dr. Ouellette. “The ultra low dose scans of the chest that we routinely perform are just slightly less than 0.1 mSv – we are talking ultra-low.”
The researchers expect to move into clinical evaluations as they are ready to roll out the new technology on a population basis. Currently, they are working with chest physicians and urologists readying trials for patient groups. Also the VCHRI team is integrating closely with industry to create CT scanners with ultra-low dose capabilities and to improve the researchers’ novel scanning techniques.
*Study co-principal investigators include Dr. Patrick D. McLaughlin, Dr. Hugue A. Ouellette, Dr. Luck J. Louis, Dr. Paul I. Mallinson, Dr. Timothy O’Connell, Dr. John R. Mayo, Dr. Peter L. Munk, and Dr. Savvas Nicolaou
Also read Part I of the story: Ultra-low dose CT scans to make x-rays obsolete