Researchers from the University of California Davis have come up with several new radiation dose reduction strategies as outlined in three articles published this month in the Journal of the American College of Radiology.
In the article "Dose Is Not Always What It Seems: Where Very Misleading Values Can Result From Volume CT Dose Index and Dose Length Product," Anthony Siebert, M.D., and colleagues described a case in which a pediatric patient underwent CT scans before and after a surgery, and appeared to receive an excessive dose of radiation during the second CT scan.
The problem was a misleading metric--in this case the volume CT dose index. The researchers reported that a new metric, size-specific dose estimate (SSDE), can provide a better way to measure patient doses and allow for a more meaningful dose estimate comparison between scanners. "I think SSDE is one step closer to a dose metric that will be more accurate in depicting the actual risk to patients," Siebert said in an announcement from UC Davis.
In a second article, "Methods for CT Automatic Exposure Control Protocol Translation Between Scanner Platforms," Siebert and colleagues looked at the issues involved with optimizing different CT scanners. While some CT protocol parameters can remain reasonably constant among different scanners, the automatic exposure control parameter will be difficult to match among scanners.
"It takes a lot of effort to optimize any given scanner," co-author John Boone, M.D. said. "Going through the procedures for every possible exam could take two years."
Siebert, Boone, and their colleagues came up with a protocol translation approach on the basis of quantitative metrics that should provide a more efficient way of managing CT protocols between different scanners
A third article, "Radiation Dose Optimization for CT-Guided Interventional Procedures in the Abdomen and Pelvis," by Ramit Lamba, M.D., outlines a variety of methods for reducing radiation dose, such as using ultrasound instead of CT to guide some biopsies, reducing scan lengths, lowering the tube current using dose efficient scanning modes and limited the number of guidance scans.
UC Davis is just one of the five UC medical centers that participate in the University of California Dose Optimization and Standardization Endeavor. "We're trying to educate radiologists and medical physicists because the practice of CT is not consistent," Boone said. "If someone is using higher doses to get results they could obtain with less radiation, we need to help them find the safer alternative."