Biological sample scanner

A method of detecting an x-ray fluorescence signal emitted from a biological sample, the method comprising: obtaining a biological sample 4a to be analysed, the biological sample 4a comprising at least one biomarker; obtaining at least one heavy-metal atom bound to an antibody to form a heavy metal-antibody conjugate, wherein the conjugate is arranged to emit a fluorescent x-ray signal when excited by an x-ray fluorescence radiation source 10; labelling the biological sample 4a with the heavy atom-antibody conjugate; illuminating the labelled biological sample with an x-ray fluorescence beam 2 emitted from an x-ray fluorescence radiation source 10; detecting an x-ray fluorescence signal emitted from the heavy metal antibody conjugate on the biological sample 4a using an x-ray fluorescence detector 7.