Magnetic resonance imaging (MRI) uses magnetic force and radio waves to create images of internal structures and tissues. MRI can reveal fine details and abnormalities more clearly than other forms of imaging. The scanner contains two powerful magnets and a radiofrequency source. One magnet creates a powerful magnetic field, which causes hydrogen atoms throughout the body to line up. The radiofrequency source emits radio waves that briefly knock the atoms out of alignment. As the atoms realign, they emit signals (resonance) that are picke up by the other magnet placed around the area being scanned. Information about the signals is transmitted to a computer; which produces an image on a monitor. MRI is often used to examine the brain and spinal cord. It is also used to investigate sports injuries such as torn tendons.

Receiving magnet

Having an MRI scan

A motorized bed moves you into the scanner, and several scans are taken. You may be given earplugs because the machine is noisy. Some people find the machine claustrophobic, and if you feel nervous, you Magnet that creates may be allowed to have someone with you. potverful magnetic field

Radionuclide scanning

Radionuclides are radioactive substances, and the radiation they emit can be used to create images. In radionuclide scanning, a tiny amount of the radionuclide is introduced into the body, usually by injection, then taken up by a specific type of tissue; for example, iodine is taken up by the thyroid gland. A device called a gamma camera detects the radiation and transmits data to a computer, which shows the tissue as areas of colour. The higher the level of cell activity in the tissue, the more radiation is emitted and the more intensely coloured the area appears. Radionuclide scans can show areas where cell activity is abnormally high, such as in tumours, or abnormally low, such as in damaged organs or cysts.

Normal kidney Damaged kidney

Having a radionuclide scan

Once your body has absorbed the radionuclide, you lie on a motorized bed that positions you over the gamma camera, which detects the radiation from the radionuclide. A computer interprets this as an image.

Motorized bed

Patella (kneecap)

End of femur (thigh bone)

Cartilage ivithin joint

Companion for patient

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