Gamma camera is the most basic imaging equipment in nuclear medicine. It consists of collimator, sodium iodide crystal, photomultiplier tube, optical matrix, position circuit, energy circuit, display system and imaging device, etc.

Collimators, crystals, photomultiplier tube, and matrices, etc, constituting parts that can be moved separately, called probe, which is the core of the gamma camera. The gamma camera can be imaged immediately in a certain field of view without the need for mechanical scanning. This instrument can be used for static observation as well as for dynamic observation.

 

Gamma camera is mainly composed of three basic components: detector, electronic circuit and monitoring device. The detector consists of collimator, scintillation crystal, light guide, photomultiplier tube, preamplifier and positioning network circuit (or analog circuit). The tungsten alloy collimator of the gamma camera is an important part of the device, which is used to achieve spatial positioning, so that rays from different space locations are irradiated to a specific position of the scintillator.

 

 

As the radioactivity of each small part of the organ is an isotropic emission ray, and the entire scintillation crystal is illuminated by it, and every point in the body also receive radiation, the flickering image formed will present a chaotic blinking point instead of the corresponding radioactive distribution image. The purpose of the collimator is to allow the ray passing through the collimator hole to be placed on the scintillation crystal to block other rays to be appeared on the scintillation crystal.

 

In addition, gamma camera can be used for rapid imaging of radioactive materials at a far distance, and the location is accurate, which can effectively reduce the radiation dose to the staff and provides a new means for the monitoring of radioactive sources and the search for lost radioactive sources. Tungsten alloy material has the advantages of high shielding ability for all kinds of radiation, and it’s environmental friendly, so it’s been widely used as shielding materials in radiation medical treatment.