On the Cover Perfusion defects in TNF-nanoparticle and heat treated tumors. Tumor perfusion in the SCK murine mammary carcinoma, hind limb model, after treatment with TNF-conjugated gold nanoparticles and/or hyperthermia, was non-invasively imaged using contrast enhanced ultrasonography. Perfused vasculature is indicated by orange-red color. Marked defects in tumor perfusion persisted in tumors receiving combined treatment. The nanoparticle (PT-cAu-TNF) is 33nm pegylated, colloidal gold coated with TNF. For details, see 1014 et al. in this issue.