'Gamma cameras' or scintillation cameras are pieces of apparatus which allow radiologists to carry out 'scintigraphy scans', tests which provide detailed diagnoses about the functioning of the thyroid, the heart, the lungs and many other parts of the body. Scintigraphy scans get their name from the ability of some crystals (such as sodium iodide) to scintillate (in other words, emit sparks) when exposed to radiation.
The procedure involves giving the patient a radiopharmaceutical molecule marked with a gamma-emitting radioisotope. Once the molecule fixed on the target organ or tissue, the highly penetrative emitted gamma rays easily escape from the body and leave their mark on the detection panels. The molecule which is followed around the body is carefully chosen with respect to the body part under examination. A very small quantity of radioactive isotope is all that is needed, as the detection systems are sensitive enough to register the decay of individual atoms.
As its name indicates, a 'gamma camera' detects scintillations produced by gamma rays emitted by a radioactive marker. Once a large number of these scintillations have been observed, the radioactive molecules emitting these gamma rays can be located.
Thanks to computer technology, complex calculations can be performed very quickly to convert the detected radiation into information that is useful for radiologists. The images, created in a fraction of a second, allow doctors to follow the spread of the radioisotope throughout a patient's body in real time. This allows for highly detailed pictures of the heart contraction, or of the filtration of blood plasma in the kidneys. A gamma camera scintigraphy can also be used to form images of the skeleton, by injecting patients with a radioactive solution which attaches itself onto the bones. This is often how skeletal metastases are detected.
The scintillation camera was invented by the American physicist H.O. Anger in Berkeley in 1957. It has since revealed itself to be an irreplaceable tool in a wide range of different diagnoses. Unquestionably the preferred piece of equipment in the field of nuclear medicine, there were 14,000 of them in the world by 1996 and much more now.
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