Using a mixture of cells isolated from an animal tumor that has been injected with a radiolabelled anti-cancer drug, we propose to quantify the exact dose of the drug accumulated in each cell of the tumor. Such an approach will make it possible to answer an essential question in pharmacology: to relate the observed effects (therapeutic and undesirable) to the dose of the drug delivered, in this case at the level of the single cell (cancer cells), but also all the other cell types present in the tumor tissue. We will build on our recent developments in antibody and molecular radiolabelling, cells capture on microfluidic devices and beta-imaging.