Real-time viewer for Positron Emission Mammography image-guided intervention

During any biopsy procedure, the targeted lesion is frequently displaced from its original position after trocar or needle insertion. To confirm the location of the lesion before tissue sampling, an additional confirmation scan is often obtained to view and adjust the needle position. For Positron Emission Mammography (PEM) guided localization procedures, a low activity radioactive line source is used to confirm the biopsy device position relative to the targeted lesion. However the typical time for a confirmation scan of 5 minutes makes real-time adjustments infeasible. We have developed a method to view PEM images in nearly real-time so as to visualize lesion displacement within 30 seconds. Phantom and patient data were collected on a high-resolution, small-organ, PET scanner (PEM Flex, Naviscan Inc., San Diego, USA). The real-time display is realized by showing only one imaging plane and calculating the intersection point of each line of response (LOR) through a plane where the lesion was targeted. A variety of refresh and persistence times from 2 to 30 seconds were evaluated. In a phantom study the point source and line source movements were successfully visualized in real-time with a refresh time of two seconds and a persistence time of 10 to 15 seconds. Simulation based on real clinical data shows that the localization of lesions can be obtained almost real-time and even relatively faint lesions with a lesion to background ratio of 2:1 can be localized in 10 seconds.