Final answer:
PET has high sensitivity due to its ability to simultaneously detect pairs of gamma rays emitted from positron-electron annihilation, pinpointing their origin with high accuracy. The use of isotopes as biological tags and advanced imaging software further enhances its diagnostic capabilities. This results in highly accurate scans, useful for detecting disorders and monitoring various physiological processes.
Step-by-step explanation:
Positron emission tomography, or PET, has a high sensitivity (true positive detection rate) because it utilizes images produced by ß+ emitters. When a positron encounters an electron, they annihilate each other, producing two gamma rays with identical energies of 0.511-MeV that travel in opposite directions. This allows detectors placed on opposite sides of the patient to simultaneously detect these photons, enabling an accurate determination of their point of origin. Further contributing to PET's high sensitivity are the computer imaging techniques that create detailed images, like those used in SPECT and CT scans.
Isotopes such as 11C, 13N, 15O, and 18F are used as markers for natural body compounds, improving the functionality of PET scans in tracking biological processes. Substances like fluorodeoxyglucose (FDG) can highlight areas in the body with increased metabolic activity, such as cancerous tissues, which consume glucose at a higher rate. Consequently, PET scans can reveal metabolic functions and abnormalities aiding in the diagnosis of diseases like Alzheimer's and in the assessment of brain function.
PET scans can also provide critical diagnostic information by noting decreased metabolism in certain regions or locating active brain regions during specific activities. This level of sensitivity makes PET an invaluable tool in modern diagnostic medicine.