Tungsten alloy collimator is a device for producing a stream of waves or particles in which the paths of all the waves or particles are parallel. To be more specific, an optical collimator is a system that transmits parallel light rays, serving as the receiving telescope or lens of a spectrometer.

Tungsten alloy collimator is used in neutron and X-ray machines. Tungsten alloy X-ray collimator filters a beam of rays so that only rays parallel to a specified direction are allowed through. It can record rays from all directions. X-ray collimator is widely used as the component part of medical accelerator radiation head.

X-ray is a form of electromagnetic radiation. X-rays increase the risk of developmental problems and cancer in those exposed. X-rays are categorized into a carcinogen by both the World Health Organization's International Agency for Research on Cancer and the U.S. government. It is considered that 0.4% of current cancers in the United States are attribute to computed tomography executed in the past. In a word, X-rays are harmful for human.

Tungsten alloy is the best material for X-ray collimators. Of all pure metals, tungsten has the highest melting point, lowest vapor pressure and the highest tensile strength, lowest coefficient of thermal expansion. So tungsten alloy X-ray collimators avoid X-rays doing harm to human when used in medicine field.