Friday, August 20, 2010

The Anger Camera

In Section 17.12 of the 4th edition of Intermediate Physics for Medicine and Biology, Russ Hobbie and I discuss the gamma camera, used in to produce images during nuclear medicine procedures. The gamma camera often goes by another name, the Anger Camera, after its inventor Hal Anger (1920-2005). Anger’s contributions to medical physics imaging rank him with giants of the field such as Godfrey Hounsfield, Allan Cormack, and Paul Lauterbur. Yet, it is harder to find information about Anger than about these other luminaries. His obituary in the New York Times stated
“Mr. Anger was known in his field for inventing the gamma camera, which was first exhibited in 1958 at a meeting of the Society of Nuclear Medicine. The device, also known as a scintillation camera and later as the Anger camera, produced images of internal processes by tracking tiny amounts of radioactive substances, known as radiopharmaceuticals, given to patients.

The invention and later improvements represented a major advance in the diagnosis and treatment of brain tumors, bone marrow disorders and other life-threatening diseases.”
Another obituary in the IEEE publication The Institute wrote
“Seen by many as a quiet genius who shaped the future of nuclear medicine, Hal took a hands-on approach to science that also led to his invention of the well counter, which is used daily in nuclear medical labs worldwide to measure small quantities of radioactive substances. He also invented the whole-body scanner, the positron camera, and the multiplane tomographic scanner.

Nuclear medicine has been profoundly affected by Hal Anger. Millions of patients have benefited from diagnosis and treatment that depended on the Anger camera and the innovations made possible by its development.”
Anger described his invention in a paper titled simply “Scintillation Camera” (Review of Scientific Instruments, Volume 29, Pages 27-33, 1958). The abstract is reproduced below.
“A new and more sensitive gamma-ray camera for visualizing sources of radioactivity is described. It consists of a lead shield with a pinhole aperture, a scintillating crystal within the shield viewed by a bank of seven photomultiplier tubes, a signal matrix circuit, a pulse-height selector, and a cathode-ray oscilloscope. Scintillations that fall in a certain range of brightness, such as the photopeak scintillations from a gamma-ray-emitting isotope, are reproduced as point flashes of light on the cathode-ray tube screen in approximately the same relative positions as the original scintillations in the crystal. A time exposure of the screen is taken with an oscilloscope camera, during which time a gamma-ray image of the subject is formed from the flashes that occur. One of many medical and industrial uses is described, namely the visualization of the thyroid gland with I131.”

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