The greatest exposure to human-made ionizing radiation for most individuals is through:

The greatest exposure to human-made ionizing radiation for most individuals is primarily attributed to medical x-rays. This is because medical imaging procedures, such as X-rays, CT scans, and fluoroscopy, are widely utilized in healthcare settings to diagnose and treat various medical conditions. The frequency and volume of these procedures contribute significantly to the overall exposure individuals receive from human-made sources of radiation.

While eating plants that may contain naturally occurring radioactive elements, such as radon, contributes to exposure, it is generally much lower compared to that from medical imaging. Similarly, emissions from nuclear power plants do have some potential for exposure, but stringent regulations and oversight typically minimize risks associated with such facilities. Buildings made of stone can emit low levels of natural radiation, particularly if they contain uranium or thorium, but again, these levels are generally lower than exposure from routine medical x-ray procedures.

In summary, while there are various sources of ionizing radiation, medical x-rays represent a significant portion of the exposure that most individuals will encounter in a typical lifetime, placing them at the forefront of human-made ionizing radiation exposure.