Gamma Camera

Developed in 1957 by Hal Anger, the Gamma Camera is sometimes called "The Anger Camera" and is still in widespread clinical use. Though the camera has been updated and improved over the past sixty years, it remains a key piece of equipment in multiple nuclear diagnostic tests.

The fundamental principle behind nuclear diagnostic tests involves introducing radioactive substances into the body and then charting the radioactive emissions given off by the decaying elements. The Gamma Camera is used to detect and chart these emissions.

Gamma Cameras are structured as such: a sheet (or sheets) of crystal are mounted to photomultipliers. When the crystal comes into contact with radiation emitting from a radioactive agent that has been introduced into the patient's system, a brief spark appears. Photomultipliers detect this spark from various angles and distances which allows a computer to accurately measure the strength and location of the source of the radiation. Compiled from all the measurements of emissions on a molecular level, the computer generates a picture of how the radioactive tracer elements are moving through the body. The crystals are so sensitive, the entire structure must be encased in lead to make certain the only radiation being detected is the radiation emitting from the patient.

Originally, photomultipliers were vacuum tubes clustered behind the crystal in a hexagonal pattern. Although this method is still in use today, technology has improved to compensate for limitations of the original design. Inaccuracies occur when two photomultipliers detect the same scintillating event and report slightly different coordinates. In the early days of nuclear medicine, this wasn't necessarily a problem because the test results generated by the Gamma Camera provided so much more information than any other method in use at the time. Today's advanced medical climate, however, demands incredible accuracy. To this end, a smaller Gamma Camera has been developed which shows promise.