The Gamma Camera

The large piece of equipment is called a Gamma Camera but it's a bit different from the cameras that you're probably familiar with!

In order to image a specific organ the radioisotope is mixed with a special pharmaceutical which is injected into a vein and then travels round the body to be absorbed by the target organ. The Gamma Camera is the piece of equipment used to detect the gamma rays from the radiopharmaceutical and to build them up into an image or series of images.

The head of the gamma camera is the part that detects the gamma rays. Cameras may have one, two or three heads - the one in the picture has two heads that can be moved into different positions. Each head has a collimator - roughly analogous to a lens followed by a crystal that converts the gamma rays to pulses of light. These pulses are amplified by photo-multiplier tubes and passed to a computer that works out where the original gamma ray came from. More computing then rejects pulses caused by scatter and builds up the image. A single image may be taken or the camera may rotate around the patient to produce a series of slices in a similar manner to CT and MRI.