Chromium-51

Chromium-51 (51Cr) is a radioactive isotope of chromium that is commonly used in medical and biological research. It has a half-life of 27.7 days and decays by electron capture to stable vanadium-51, emitting gamma radiation in the process.

Production

Chromium-51 is produced in a nuclear reactor by neutron activation of stable chromium-50. The reaction is as follows:

50Cr(n,γ)51Cr

The produced 51Cr is then purified from the other reaction products to obtain a pure source for use in research.

Uses

Chromium-51 has several uses in medical and biological research. One of the most common uses is in the red blood cell survival studies. In this application, a patient's red blood cells are labeled with 51Cr and then returned to the body. The rate at which the radioactive cells disappear from the body can then be used to determine the lifespan of the red blood cells.

Another use of 51Cr is in the measurement of gastrointestinal bleeding. In this application, the patient's red blood cells are labeled with 51Cr and then returned to the body. The patient's stool is then monitored for radioactivity, which would indicate bleeding in the gastrointestinal tract.

Safety

As with all radioactive materials, care must be taken when handling chromium-51 to avoid unnecessary exposure to radiation. The primary hazard is from the gamma radiation emitted during decay, which can penetrate the body and cause damage to tissues and organs. Therefore, shielding and distance are important factors in reducing exposure.

See also

• Isotopes of chromium
• Radioactive tracer
• Nuclear medicine

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