Radioisotope technology - tracers

Geiger counter Iodine-131 Nuclear medicine

In recent years, the development of and further research into nuclear technology has lead to the ever-increasing usage of radioisotopes in Biology, particularly as tracers to track the path of elements through living plants and animals, furthering our understanding of the systems which operate within organisms.

A Geiger CounterRadioisotopes are isotopes - atoms of the same element with a different number of neutrons in the nucleus - that are radioactive. This radioactivity means that they have an unstable nucleus which undergoes radioactive decay into a more stable state; this process releases alpha and/or beta particles, and/or gamma rays. They can used as tracers in biology and medicine to "mark" the pathways of which certain elements take in plants and animals because they behave in the same way as their non-radioactive counterparts. Using technology such as Geiger counters, autoradiography, gamma ray spectrometers, scintillation counters, Positron Emission Tomography, SPECT and nuclear imaging, we can detect the radiation emitted from the radioisotopes as they decay and trace the paths that the elements take. In addition to this, the development of technologies such as nuclear reactors and cyclotrons means that we can not only rely on the 50 naturally occurring radioisotopes that exist in nature, but also manufacture new ones when needed.

A Geiger counter is used to detect radiation released from radioisotopes as they decay. This works on the principle that gases can only conduct electricity when ionized. Electrons and Ions that are emitted from the radioactive decay of radioisotopes have the capacity to ionize gases. The Geiger counter contains a metal cylinder with a thin wire along the middle. The tube is then filled with gas - normally argon. The radiation is detected through the "window" end and knocks electrons off the gas molecules - ionizing them and starting a chain reaction where more gas molecules are ionized. These atoms congregate near the...
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