Which type of radiation is used in medical imaging?

Gamma radiation is commonly used in medical imaging due to its unique properties. It is a form of electromagnetic radiation with a very high frequency and energy, which allows it to penetrate tissues effectively without causing significant damage. In medical imaging, gamma rays are utilized in techniques such as positron emission tomography (PET) scans and single photon emission computed tomography (SPECT) scans. These techniques allow physicians to visualize internal organs and detect abnormalities by using radioactive tracers that emit gamma rays. The ability of gamma radiation to go through the body and be detected externally makes it invaluable for diagnostic purposes.

In contrast, alpha radiation consists of heavy, positively charged particles that have low penetration power and can be stopped by a sheet of paper or even human skin, making it unsuitable for medical imaging. Beta radiation, which consists of lighter charged particles, can penetrate tissue more than alpha particles but is still not as effective for imaging as gamma radiation. Cosmic radiation, originating from outer space, is not used in medical imaging because it is not generated specifically for diagnostic purposes and presents challenges due to its variability and high-energy particles that can pose risks to patients and equipment.