Conventional PEM images are acquired with a 10-mCi dose of radiopharmaceutical. Researchers from Swedish Medical Center and the University of Washington, including co-author Dr. James Rogers, instead tried a 5-mCi dose in a small population of five patients.

The lower dose resulted in longer exam times, from seven minutes to 10 minutes. However, the longer uptake time of 90 to 120 minutes with the lower dose significantly improved lesion-to-background ratios when imaging invasive ductal carcinoma, the researchers found.

The researchers said they are still formulating their strategy with doses that are even lower than 5 mCi, and they hope to develop individualized dose protocols based on patient weight.