A digital phantom of the axilla based on the visible human project data set

In this paper, we describe the development of a new digital phantom designe d for Monte Carlo simulations of breast cancer and particularly positron em ission tomography (PET) imaging of the axillary lymph nodes. The phantom wa s based on data from the Visible Human Project female data set. The phantom covers the head-to-diaphragm regions; 17 major tissue types were segmented and 66 individual lymph nodes were identified. We have used the phantom in Monte Carlo simulations to model a reduced field-of-view PET imager based on two flat plate arrays placed on either side of the shoulder. Images used a simple single angle set of projections. We have conducted two preliminar y studies: one modeling a single-frame PET acquisition 60 min after FDG inj ection and the other modeling a dynamic PET acquisition simulating four tim e frames after FDG injection. The dynamic results were processed into param etric images using the Patlak method and show the advantage to be gained by including the temporal information for legion detection. Our preliminary r esults indicate that the performance of such an imager forming projection i mages is not sufficient for axillary node PET imaging.