Coloured scanning electron micrograph (SEM) of a small blood clot detaching from a PICC (peripherally inserted central catheter) line internal surface. The red blood cells are at bottom with the platelet clotting at top. A PICC line is used to give chemotherapy or other treatments such as liquid nutrition. It is a long, thin, hollow, flexible tube, threaded along a vein until the tip is in a large vein just above the heart. The inside of the line can sometimes become partly or completely blocked. Magnification: x1000 when printed at 10 cm wide.