Ligaments attach your breasts to the pectoral muscle on your chest. When you wear a bra, your supported breast does not allow the pectoral muscle to be exercised as much as it could be. When you do not wear a bra, as you move your arms, reach, and lift, your pectoral muscle is strengthened.
Positron emission tomography. Positron emission tomography (PET) is a nuclear medicine functional imaging technique that is used to observe metabolic processes in the body. The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule.
Developed in 1975, the PET scan is a diagnostic tool that allows doctors to picture of how the cells in your body are working and to detect abnormalities. You may not have heard as much about PET scans as you have about MRIs and CT scans.