Hello everyone, can you tell us about radionuclides in medicine? Their purpose and mechanism of action
In short, as I understand it, certain pathological tissues, such as cancerous ones, accumulate these drugs, and as a result, radionuclides expose these tissues to radiation, which leads to their damage.
There are also diagnostic radiopharmaceuticals that accumulate in certain tissues and can also be registered and determined.
Some isotopes are unstable and radioactive, and are called radioisotopes. Radioisotopes do not have the correct neutron to proton ratio in their nucleus to be stable or they have excess energy. In an attempt to become stable, radioisotopes emit excess particles and/or energy in the form of ionising radiation. The process of emitting ionising radiation is called radioactive decay, and is measured with a time period called a half-life. One half-life is the amount of time it takes for half the radioactive atoms of a radioisotope to disintegrate and, thus, the time taken for a measured level of radioactivity from the radioisotope to reduce to one half of the original level.
Most radionuclides used in medicine need to be attached to a biologically active molecule to get to the desired organ. Doctors and chemists have identified a number of chemicals which are absorbed by specific organs. The thyroid, for example, takes up iodine, whilst the brain consumes quantities of glucose. With this knowledge, radio-pharmacists are able to attach various radionuclides to biologically active substances. These radionuclide-tagged molecules are called radiopharmaceuticals. After entering the body, the radiopharmaceutical will accumulate in a specific organ or tumour tissue. The radionuclide attached to the targeting molecule will undergo decay and produce specific amounts of radiation that can be used to diagnose or treat human diseases and injuries. The radiopharmaceutical is incorporated into the normal biological processes and excreted from the body in the usual ways.
@ekaterina-gribacheva I didn’t quite understand what the correct ratio of protons and neutrons in the nucleus means
@argentum By "correct" I mean a stable state, that is, the ratio at which there is no decay
@argentum Every time when you have an isotope - the isotope is decaying. The "correct" ration is when number of protons is equal to number of neutrons.