When matter is irradiated by x-rays, what type of radiation is produced?

• A. Secondary radiation
• B. Primary radiation
• C. Tertiary radiation
• D. Quaternary radiation

Answer: (A)

Secondary radiation is produced when the x-ray beam interacts with matter. The primary radiation is the original beam emitted by the x-ray tube, but once it hits matter (like a patient or surrounding objects), interactions such as Compton scattering and the emission of characteristic x-rays create new photons. These scattered or secondary photons travel away from the matter and contribute to the radiation field. Tertiary and quaternary terms aren’t used to describe this process in dental radiology.