What is the inverse square law ?
The inverse square law is a geometric relationship that expresses the intensity of energy emitted by a point source as a function of the distance from that source. It assumes that energy dissipates equally in all directions and that its intensity is inversely proportional to the square of the distance r from the source (i.e., 1/ r 2 ). The inverse square law is applicable to different types of electromagnetic radiation, including radio waves, light, x-rays, and gamma rays. For this reason, it is a tenet of radiation safety for radiation workers who use fluoroscopy: by doubling one’s distance from the x-ray tube of the fluoroscope, one’s radiation exposure is decreased by 75%.