Role of radio isotopes in dating the past Chatral gril xxx
The earliest technique developed uses single photons detected by a gamma camera which can view organs from many different angles.
The camera builds up an image from the points from which radiation is emitted; this image is enhanced by a computer and viewed on a monitor for indications of abnormal conditions.
Single photon emission computerised tomography (SPECT) is the current major scanning technology to diagnose and monitor a wide range of medical conditions.
A more recent development is positron emission tomography (PET) which is a more precise and sophisticated technique using isotopes produced in a cyclotron.
In developed countries (a quarter of the world population) about one person in 50 uses diagnostic nuclear medicine each year, and the frequency of therapy with radioisotopes is about one-tenth of this.
As it decays it emits a positron, which promptly combines with a nearby electron resulting in the simultaneous emission of two identifiable gamma rays in opposite directions.Gamma imaging by either method described provides a view of the position and concentration of the radioisotope within the body.Organ malfunction can be indicated if the isotope is either partially taken up in the organ (cold spot), or taken up in excess (hot spot).In most cases, the information is used by physicians to make a quick diagnosis of the patient's illness.The thyroid, bones, heart, liver, and many other organs can be easily imaged, and disorders in their function revealed.
Nuclear medicine was developed in the 1950s by physicians with an endocrine emphasis, initially using iodine-131 to diagnose and then treat thyroid disease.