Positron emission tomography (PET) imaging is based on the annihilation of which particles?

Positron emission tomography (PET) imaging relies on the annihilation of positrons and electrons. In PET, a radiotracer that emits positrons is introduced into the body. When these positrons encounter electrons, they undergo a process called annihilation, where the mass of both particles is converted into energy in the form of gamma photons. This annihilation produces two gamma rays that travel in opposite directions, which are detected by the PET scanner to create images of the metabolic activity within the tissues.

This mechanism is fundamental to PET imaging, as it enables the visualization of processes such as glucose metabolism in tumors. The ability to track these interactions allows for assessing various physiological functions, making PET a powerful tool in both diagnosis and treatment monitoring in oncology, cardiology, and neurology. Understanding the role of positrons and electrons in this process is crucial for those studying medical dosimetry and related fields.