Final answer:
Positron emission tomography (PET) scans use radioactive tracers to investigate tissue function by tracking the uptake of radiopharmaceuticals, revealing metabolic and physiological activity, and different radioisotopes are used to target specific tissues or conditions.
Step-by-step explanation:
One can investigate the function of tissues by scanning for a radioactive tracer through an imaging technique known as positron emission tomography (PET) scan. This process involves the use of radiopharmaceuticals to reveal metabolic and physiological functions in tissues. A positron-emitting radioisotope is produced in a cyclotron and attached to a substance utilized by the body part under investigation. This radiotracer is administered to the patient, and its uptake by tissues informs us about their functioning.
Radioisotopes like technetium-99, thallium-201, iodine-131, and sodium-24 are employed for this purpose. For instance, technetium-99 compounds, injected into the body, can help identify damaged heart, liver, or lung tissues by tracing the emitted gamma rays. Similarly, thallium-201 helps highlight healthy heart tissue, while iodine-131 is significant in thyroid monitoring and treatment. Sodium-24 compounds via injection can detect blood flow obstructions.
PET scans are particularly effective in identifying metabolically active tissues, such as cancer cells that consume glucose at a high rate, which become visible as bright "hot spots" in the images produced by the PET scanner.