X-ray image of a patient's chest whilst undergoing a cardiac catheterisation procedure. The catheter may just be seen as the dark line running vertically from the top centre of the frame. The catheter is running through a vein, having been inserted in the patient's arm, and has reached the area of the heart. At the end of the catheter is a micromenometer, a tiny pressure sensor, that makes pressure observations on either side of a heart valve. The sensor is no larger than the tip of the catheter itself, having been made by the new technology of micromechanics.