Isotopes medical imaging

The isotope molybdenum-99 is produced in large quantity as the precursor to technetium-99y, a radionucleide used in numerous medical imaging procedures such as those of bone and the heart (see Medical imaging technology). The molybdenum-99 is either recovered from the fission of uranium or made from lighter Mo isotopes by neutron capture. Typically, a Mo-99 cow consists of MoO adsorbed on a lead-shielded alumina column. The TcO formed upon the decay of Mo-99 by P-decay, = 66 h, has less affinity for the column and is eluted or milked and either used directly or appropriately chemically derivatized for the particular diagnostic test (100). 

Because exposure to radiation is a health risk, the administration of radioactive isotopes must be monitored and controlled carefully. Isotopes that emit alpha or beta particles are not used for Imaging, because these radiations cause substantial tissue damage. Specificity for a target organ is essential so that the amount of radioactive material can be kept as low as possible. In addition, an Isotope for medical Imaging must have a decay rate that is slow enough to allow time to make and administer the tracer compound, yet fast enough rid the body of radioactivity in as short a time as possible. 

Positron emission tomography (PET) A medical imaging technique that helps physicians locate tumors and other growths in the body. A radioactive tracer isotope which emits a positron is incorporated into a metaholically active molecule. A scanner locates the tissues where the radioactive substance winds up. 

Radioactive Isotopes Are Useful as Tracers and for Medical Imaging... 

RADIOACTIVE ISOTOPES ARE USEFUL AS TRACERS AND FOR MEDICAL IMAGING... 

In a technique known as medical imaging, tracers are used in medicine for the diagnosis of internal disorders. Small amounts of a radioactive material, such as sodium iodide, Nal, which contains the radioactive isotope iodine-131, are administered to a patient and traced through the body with a radiation detector. The result, shown in Figure 4.11, is an image that shows how the material is distributed in the body. This technique works because the path the tracer material takes is influenced only by its physical and chemical properties, not by its radioactivity. The tracer may be introduced alone or along with some other chemical, known as a carrier compound, that helps target the isotope to a particular type of tissue in the body. 

Which of the following isotopes is commonly used for medical imaging in the diagnose of diseases ... 

Iodine (chemical symbol I) is a nonmetallic solid element. There are both radioactive and non-l adioactive isotopes of iodine. Iodine-129 and -131 are the most important radioactive isotopes in the environment. Some isotopes of iodine, such as 1-123 and 1-124 are u.sed in medical imaging and treatment, but are generally not a problem in the environment because tliey have very short half-lives. 

A radioisotope of technetium is useful in medical imaging techniques. A sample initially contains 80.0 mg of this isotope. After... 

The possibihty to quantify in vivo biochemistry noninvasively using compounds labeled with radioactive isotopes is a milestone in medical imaging. The first production of the short-Kved positron emitting radionuchde was performed in 1934 (Crane and Lauritsen 1934). It was found that decays with a half-hfe of 20.4 min by positron emission to the stable nuchde... 

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