Radiation sources are materials or devices that emit radiation, which can be in the form of alpha particles, beta particles, gamma rays, or X-rays. These sources can be natural, such as radon gas found in soil, or artificial, like those used in medical imaging and treatments, including X-ray machines and radiotherapy equipment. Common applications of radiation sources include medical diagnostics, where radiopharmaceuticals are used for imaging, and industrial uses, such as radiography for inspecting welds and materials. Understanding these sources is essential for ensuring safety and effective use in various fields, including healthcare and manufacturing.