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++++++++++++++ + + ++++++++++++++ IMAGING +++ +++ When Less Is More IN RADIOLOGY THE FIELD OF RADIOLOGY HAS SUCCESSFULLY LOWERED THE RATES OF RADIATION EXPOSURE IN COMPUTED TOMOGRAPHY (CT) SCANS SINCE GODFREY HOUNSFIELD CONDUCTED THE FIRST BRAIN SCAN IN 1971. TODAY, CONSULTING RADIOLOGISTS, LTD. IS DEMONSTRATING THE SUCCESS OF REDUCING RADIATION EXPOSURE TO FRACTIONS OF CURRENT DOSES THROUGH THE USE OF ADAPTIVE STATISTICAL ITERATIVE RECONSTRUCTION (ASIR) TECHNOLOGY. AS ROBIN PARKER, M.D., dia gnos t ic radi - ologist at Consulting Radiologists, Ltd., explains, radiation exposure levels have progressively decreased over the last 100 years. Since the publication of the BEIR VII report in 2005 (see "Research's BEIRing on Patient Care"), manufacturers have committed additional resources in product development toward low radiation dose equipment. Consulting Radiologists, Ltd. follows the American College of Radiology recommended policy ALARA — as low as reasonably achievable — which supports the use of radiological studies only when necessary and appropriate. With the advent and adoption of ASIR software, the ALARA rule of thumb is enhanced considerably without any compromise to image quality. "Primary care physicians can still order the same imaging scans they have always ordered," says Dr. Parker. "The shift is in the knowledge that they are receiving; the same quality of image with a lower dose of radiation." The Radiological Approach to Safety There are several steps employed to 6 | Twin Cities MD NEWS MDNEWS.COM reduce the level of radiation exposure. Beyond avoiding unnecessary scans, radiologists can adjust the dosage accord- ing to the size of the patient. When scanning smaller patients, less radiation is required to pass through the body to form the image. In the same vein, radiation levels can be tailored to the location being imaged. The lungs contain less tissue than the abdomen or chest and thus, less radiation is needed to pro- duce the same quality image. This kind of adap- tive technology is Robin Parker, M.D. now standard in most imaging hardware. Subtraction for a Greater Sum At CRL Imaging Edina, Consulting Radiologists, Ltd. is incorporating the latest technology for dose reduction into its CT imaging capabilities, coupling a GE BrightSpeed Elite 16-slice CT scanner with ASIR software. First, a low-radiation dose scan is performed. The new software is then applied to the image, systematically and repetitively subtracting the noise from the image. The resulting image is equal in quality to images produced with higher levels of radiation and is achieved with 30% to 40% reduction in radiation dosage. "The noise is what degrades the quality of the image. However, because math- ematically we know where the noise will be coming from and how much noise there will be, the software can separate it from the image," says Dr. Parker. The Cancer-Screening Connection For patients, the advantage of the ASIR technology lies in its long-term implications. The average patient who receives an isolated CT scan for a specifi c injury or diagnosis will benefi t from the lower radiation dose. However, a patient with a chronic condition who must be imaged multiple times annually for many years will accumulate far smaller levels of radiation exposure over the course of his or her lifetime, thanks to the technology. ASIR software also holds potential benefi ts for lung cancer screenings. The National Lung Screening Trial (NLST), which included 50,454 current or former heavy smokers between the ages of 55 and 74, compared the mortality rates of participants tested with chest X-ray and those tested with low-dose helical

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