Which energy is detected by PET?

Positron Emission Tomography (PET) detects the energy released during the annihilation of positrons. When a positron emitted from a radioactive tracer encounters an electron, they annihilate each other, resulting in the production of two gamma photons. These photons each have an energy of 0.511 MeV (megavolts).

The correct answer indicates 511 kV, which is equivalent to the correct energy measurement of these gamma photons after conversion from MeV to kV. Since 1 MeV equals 1000 kV, 0.511 MeV can be expressed as 511 kV.

This detection process is fundamental to PET imaging, as it allows for the visualization of metabolic processes in tissues. The other energy values provided do not correspond to the energy of the gamma photons produced in this annihilation process, making them incorrect.