Will. Positron emission tomography is needed to find a process in our body. For this, a tracer is used. That is, a special drug that is fixed somewhere in our body and knows how to create some kind of radiation around itself.
This drug is radioactive, but weak and does not cause much harm. The radioactive isotope fluorine-18 is commonly used.
In fact, several isotopes can be used there, but fluorine-18 is more often remembered. In my opinion, this fluoride-18 simply lives longer than other drugs and is easier to use. Longer means its half-life is only a couple of hours. The rest of the isotopes live even less.
Since such a drug does not last long, it must be prepared in a special radioactive kitchen immediately before the examination. It turns out that the positron emission tomograph is being built as a separate town, in which there will be a laboratory for creating a radioactive tracer. Therefore, such an examination is expensive.
Fluorine-18 is made from the heavy isotope oxygen-18. Oxygen-18 is not some kind of radioactive muck from a nuclear reactor, but a peaceful heavy isotope of oxygen that we breathe. Its content in ordinary atmospheric oxygen is somewhere around 0.2%.
Have you heard about oxygen concentrators? They saved the people for the last couple of years. So if we go further, then it is possible not only to concentrate oxygen from the air, but also to divide it into more or less heavy isotopes inside the oxygen.
In this way, a heavy isotope is concentrated from oxygen, mixed into water and bombarded with particles in a special accelerator in that radioactive kitchen. This is how water is obtained with fluorine-18 ions floating in it.
Then this fluorine-18 is added to glucose, and the glucose becomes labeled. Then the resulting tracer is delivered at a run to the tomograph, this labeled glucose is poured into the patient and scanned with the tomograph. Glucose is most often labeled, but there are other drugs.
The labeled glucose goes wherever some kind of action is taking place. Usually this is a tumor that grabs and eats any glucose floating by. But not necessarily. You can just watch our brains feed on glucose. Also, they say, a fascinating sight. Neurologists in this way watch how epilepsy flares up in some part of the brain.
So if an isotope accumulates in a tumor, then it can be noticed there. It emits positrons. These are antiparticles, similar to electrons, but only with a positive charge. Positrons annihilate with electrons and, as a result, a pair of gamma quanta is released, which is noticed by the tomograph and draws on the tomogram the place in which this whole thing takes place. Elementary! Antiparticles, annihilation, spaceships, all things ...
After work, tired fluorine-18 turns into peaceful oxygen-18, which is gradually removed from our body. The problem is that not only peaceful oxygen-18 is removed, but also vigorous fluorine-18, which with its positrons is considered a source of beta radiation. That is, detectors at the airport will yell at him, he can spoil growing organisms, be harmful to children and pregnant women.
Therefore, after the examination, it is better for 6 hours not to approach children and pregnant women. This radioactive garbage can fly out of you several meters and penetrate several centimeters into various materials and living organisms. So sit at home and drink more water. So it is faster excreted in the urine.
There is a chance that within a week after the examination, radiation detectors at the airport will swear at you. So don't go there again.
Available?
