You want the tracer to have a short half-life so that its radioactive impact to the object you are examining (usually, some organ in the body) is minimized.
The best known example of a tracer is technicium-99m, with a low energy gamma photopeak of 140.511 KeV and a half-life of only 6 hours. Since this is a meta-stable form of technicium-99, there is no beta or alpha emission, making this an ideal tracer.
Radioactive compounds used in diagnosis are chosen because specific organs or types of tissue absorb them more than other compounds. By observing the emission of radiation, a picture of an organ can be obtained that is rather like an X-ray photograph.
Part of the trick to radio diagnosis is to expose the patient to the least amount of radiation possible. There is a certain amount of radiation that is required to get the picture. We want the patient to be exposed to as little additional radiation as possible. Another way of putting this is that the length of time needed to make the picture has the greatest possible portion of the total exposure of the patient to radioactive material.
One way to do this is to use materials with short half lives. The total amount of radioactive material is decreased, and the total exposure is as short as possible.
This minimizes the harmful side effects of the radiation.
A short half-life means the material only remains radioactive for a short time and does not continue to release radiation into the patient or environment.
It is important to limit the total radiation exposure.
So they will clear the body as soon as possible after the test or treatment is complete, minimizing side effects.
The use of radioisotopes for diagnostic or treatment is permanently checked and under severe cotrol, to avoid possible and unfortunately known accidents.
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That varies, but as most radioisotopes produced in a typical nuclear blast are short halflife, the area is likely to be safe to reoccupy in a few weeks to months. It gets more complex to predict with many blasts (especially high fallout surface bursts). Radiological surveys should be taken first to identify any radioactive hotspots so they can be marked off as hazard zones.
There are several radioactive forms of carbon. The most familiar, used in carbon dating, is carbon-14. All of the others have very short half-lives.Isotopes of carbon range from carbon-8 to carbon-22. Carbon-12 and carbon-13 are stable and non-radioactive. Carbon-14 has a half-life of 5730 years. The longest lived beyond that is carbon-11 at 20.3 minutes.
An atom of a given isotope will undergo radioactive decay whenever it feels like it. No joke. The nucleus of a radioactive isotope is unstable. Always. But that atom has no predictable moment of instability leading immediately to the decay event. We use something called a half life to estimate how long it will take for half a given quantity of an isotope to undergo radioactive decay until half the original amount is left, but this is a statistically calculated period. No one knows how long it will take a given atom of a radioactive isotope to decay, except that those with very short half lives will pretty much disappear relatively quickly.
Radioactive decay may be used in carbon dating, testing for the amounts of a radioactive carbon isotope (C14) in the remains of some organism. C14 obviously only works on organic material which was once alive, such as wood or bone. Because C14 has a very short half life, less than 6000 years, it does not work on material much over 60,000 years (about ten half lives). Potassium/Argon is another useful set of isotopes that can yield the ages of rocks and inorganic matter far older--many millions of years old.
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Your question makes no sense.ordinary hydrogen has 1 proton and no neutronsdeuterium has 1 proton and 1 neutrontritium has 1 proton and 2 neutrons, it is radioactive with a halflife of about 12 yearsThere are more isotopes of hydrogen with more neutrons, but they are radioactive and have such short halflives that they are nearly undetectable.
It can be used in medicine, they use a radioactive isotope of a very short half life to help diagnose medical conditions.Carbon 14 can also be used to date organic material and is determined by the decay rate and comparison of carbon-14 to carbon-12 as carbon-14 is a radioactive isotope and will hence decay at a half life of 5720 years. radioactive isotopes can be used todetermine the ages of rocks and fossilsto treat cancer and kill bacteria that causes food to spoilas "tracers" to follow the movements of substances within organisms
Uranium-235Uranium-233Plutonium-239DeuteriumTritiumAs tritium is radioactive with a short halflife (12 years), weapons using it age rapidly possibly becoming unreliable. Therefore it is normally produced from Lithium (in the form of Lithium Deuteride) by fission neutron bombardment just before fusion is initiated.
Rub it off Radioactive polonium brushes available in any photoshop will do this. The alpha particles emitted by the polonium ionize air and the ionized air carries off the static charge. These brushes should be bought new at least every year from a fresh batch at the photoshop due to the short halflife of polonium.
Francium has an extremely short half life of about 20 minutes so no it is not. Radioactive lasers do not use radioactive materials anyway.
K. E. White has written: 'Short notes on dilution gauging methods and suitable water tracers'
You think probable to isotopes; but the most important isotope of artificial radioactive elements is included in the periodic table.
As a radioactive element with a short half life astatine is dangerous.
That varies, but as most radioisotopes produced in a typical nuclear blast are short halflife, the area is likely to be safe to reoccupy in a few weeks to months. It gets more complex to predict with many blasts (especially high fallout surface bursts). Radiological surveys should be taken first to identify any radioactive hotspots so they can be marked off as hazard zones.
sure, but all will be radioactive with short halflives.