What is the role of collimators in SPECT/PET gamma cameras?

Collimators play a crucial role in SPECT (Single Photon Emission Computed Tomography) and PET (Positron Emission Tomography) gamma cameras by focusing and filtering gamma photons. Their primary function is to allow only those photons traveling in specific directions to reach the detector, which improves the spatial resolution of the images produced. By filtering out photons that are scattered or not traveling directly from the source to the detector, collimators help to enhance image quality, making it easier to differentiate between tissues or detect abnormalities.

The configuration of the collimator, such as its type and geometry (parallel-hole, pinhole, or cone-beam), is designed to optimize the detection process for specific imaging requirements. While other functions such as enhancing image contrast or measuring radiation dose are important in nuclear medicine, they are not the primary functions of collimators in the context of SPECT/PET imaging.