Early clinical studies used ex vivo [111In]In-oxine labelling of CD4+ T-cells (1.2 x 109 cells with 6.7 MBq) to demonstrate sequestration of CD4+ T-cells in Hodgkin's lymphoma lesions with SPECT imaging 108, or accumulation of adoptively transferred ex vivo expanded tumour-infiltrating lymphocytes in melanoma patients 109, 110. The gene discussed is CD4; the disease is neoplasm.