The Fludeoxyglucose F 18 Injection (FDG) dose for positron emission mammography (PEM) may be reduced by at least 50% without altering image quality, according to a study by researchers from Swedish Medical Center and the University of Washington.

PEM is the breast application of the Naviscan high-resolution PET scanner showing the location as well as the metabolic phase of a lesion.

Preliminary results from five patients with invasive ductal carcinoma as well as phantom images show that PEM lesion detection at a 5 millicurie (mCi) injected dose of FDG, or 50% lower than the dose commonly used in clinical practice, yielded comparable sensitivity while maintaining lesion detectability.

The results also revealed that injected dose could be reduced further for lighter patients or with concordant increased scan time.

The results are part of an ongoing clinical trial at Swedish Medical Center with the goal of determining the lowest optimized dose levels of FDG required to produce high quality PEM images in patients with breast cancer.

Seattle Nuclear Medicine nuclear medicine physician and co-author of the study James Rogers said the tradeoff between lowering dose and minimally increasing imaging scan time from a 7 to 10 minute scan appears to be a reasonable imaging strategy.

"We are still formulating our opinion and strategy in regard to lower FDG doses that are less than 5 millicuries, and are hopeful that an individualized patient strategy based on patient weight will allow us to show that lower FDG doses will be possible for a large number of our patients. We have not done enough DCIS only patients or Invasive Lobular patients to make a conclusion at this time," Rogers said.

The Naviscan PET scanner is currently installed and available in breast and imaging centers throughout the US and other parts of the world.