"The study included 291 patients who underwent CT-guided biopsy, needle aspiration or catheter placement procedures," said Brian Lucey, MD, Assistant Professor at Boston University Medical Center.
"These patients undergo diagnostic imaging examinations before they come in for their image-guided interventional procedures," said Dr. Lucey. These initial examinations are performed using standard radiation doses (175 to 250 mAs depending on the size of the patient). In the past, "we also used standard radiation doses when we performed the interventional procedure, but we really do not require diagnostic quality images. Which means, that we can dramatically reduce the radiation dose--when we perform the interventional procedure," he said. "We can successfully perform biopsies, needle aspirations and place catheters even if the image is a little muddy," he added.
"Two hundred and one percutaneous biopsy procedures were performed using 30 mAs, and the technical success rate was 93.5%," said Dr. Lucey. "The technical success rate for biopsies performed using standard radiation dose in the 12 months prior to introducing the low dose radiation technique was actually lower – 87.5%," he said. It's important to note that "we can start with a very low dose and increase the dose if the procedure is not feasible at the lowest dose," Dr. Lucey said. In 12 patients undergoing biopsy, the low dose technique was unable to successfully identify the masses and these procedures were completed using a higher radiation dose, but all were successfully performed using a radiation dose lower than the standard dose," he said.
Ninety percutaneous aspirations or catheter placement procedures were done, and all but three were successful using 30 mAs, yielding a success rate of 96.7%. In two of those patients, the radiation dose was increased to 65 mAs and in the third patient the dose was increased to 200 mAs and then was successful.
"We routinely do these procedures using 30 mAs," said Dr. Lucey. "This study shows that you can go as low a 30 mAs, but if a radiologist feels uncomfortable going that low, it is important to remember that any decrease below the standard dose is good," he said.
The full results of the study will be presented on May 1, 2006 during the American Roentgen Ray Society Annual Meeting in Vancouver, BC.
About ARRS
The American Roentgen Ray Society (ARRS) was founded in 1900 and is the oldest radiology society in the U.S Radiologists from all over the world attend the ARRS Annual Meeting to take part in instructional courses, scientific paper presentations, symposiums, new issues forums and scientific and commercial exhibits related to the field of radiology. The ARRS is named after Wilhelm Röentgen, who discovered the x-ray in 1895.
Journal
American Journal of Roentgenology