A gamma camera is a piece of medical equipment that is capable of detecting gamma radiation. The radiation can be recorded on film or displayed on a monitor. These devices are used in medical imaging studies that are designed to show doctors what is happening inside a patient's body. Such procedures are minimally invasive and can be performed in a hospital or clinic.
For an imaging study with a gamma camera, a patient ingests or inhales a tracer material that emits gamma radiation. The tracer can also be injected. It may include a substance that is designed to tag particular types of tissue in the body, or it can be introduced to a specific region of interest, such as the heart or the lungs. The gamma camera is positioned over the patient and as the tracer material travels through the body and emits radiation, the camera picks it up.
A crystal inside the head of a gamma camera scintillates in response to radioactive particles, producing a burst of light that is picked up by sensors located behind the crystal. The camera constructs an image based on this information. When a single camera is used to make two dimensional images, the process is known as scintigraphy.
It is possible to use multiple gamma cameras to generate a three dimensional image. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) scans both use this technology. The cameras may be positioned in several locations around the patient and moved as the study proceeds to generate a series of images that can be developed into a three dimensional representation of the interior of the patient. Three dimensional medical imaging provides doctors with an opportunity to view as much of the area of interest as possible.
Gamma cameras can be used in diagnosis and to follow up on the course of treatment. Medical imaging studies are used to identify cancers, congenital abnormalities, and other problems inside a patient's body. The images can be used to plan a course of treatment, such as chemotherapy to attack cancers or surgery to correct heart valve defects. Images are also useful for monitoring patients in treatment as the images can be used to see if the patient is responding to the treatment.
Radiation can be dangerous. Nuclear medicine like the use of a gamma camera for diagnosis is supervised by someone with specialized training and it is only recommended when it is medically necessary.