Fine-needle aspiration cytology (FNAC), is a diagnostic procedure used to investigate lumps or masses. In this technique, a thin, hollow needle is inserted into the mass for sampling of cells that, after being stained, will be examined under a microscope.

Image guided FNAC has facilitated easy collection of cellular material with greater accuracy. Previously inaccessible sites, like the intra-thoracic and intra-abdominal lesions can be safely sampled and are now routinely aspirated under image guidance to yield cellular material.