Radio-labelling of blood cells is an established technique for evaluating in vivo migration to sites of pathology such as infection and haemorrhage. We describe the use of two methods of cell labelling for tracking the destination of autologous-derived macrophage activated killer (MAK) cells linked to the bi-specific anti-her2neu antibody MDX-H210 delivered either by intravenous (iv) or intraperitoneal (ip) injection in ten patients with peritoneal relapse of epithelial ovarian carcinoma. Our results demonstrate the feasibility of generating high numbers and purity of GMP quality MAK cells, which can be efficiently radiolabeled. MAK cell administration produced minimal infusional toxicity and demonstrated a reproducible pattern of in vivo distribution to the lungs, liver and spleen in addition to active in vivo tracking to sites of known tumor following either iv (8 of 16 infusions) or ip (4 of 6 infusions) using either 18F-FDG or 111In-labelled cells. The addition of MDX-H210 monoclonal antibody did not alter the distribution of cells to tumor sites, but did alter the in vivo distribution of cells administered by iv injection. This study demonstrates that cellular cancer immunotherapies may be successfully delivered to sites of active tumor and allows selection of those patients who may benefit from these approaches.