To produce collimated light you can either place an infinitesimally small source exactly one focal length away from an optical system with a positive focal length or you can observe the point source from infinitely far away.

What is collimator made of?

The collimator is made of perforated or folded lead and is interposed between the patient and the scintillation crystal. It allows the gamma camera to localize accurately the radionuclide in the patient's body.

What is a collimated lens?

Collimating lenses are curved optical lenses that make par- allel the light rays that enter your spectrometer setup. ... Single and achromatic lenses are available. In simplest terms, collimation ensures that light rays travel parallel to each other and don't disperse in unwanted direc- tions.