What is the approximate range of potential difference used in diagnostic radiography?

• A. 100-250 kV
• B. 50-120 kV
• C. 10-100 kV
• D. 80-150 kV

Answer: (B)

Kilovoltage peak (kVp) sets the energy of the X-ray photons and thus how penetrating they are. In diagnostic radiography, a typical operating range is about 50 to 120 kV because this span provides enough penetration for most body parts while preserving workable image contrast. Lower kV increases subject contrast but requires higher mA or longer exposure, which raises patient dose. Higher kV reduces image contrast and can reduce dose for thicker parts, but if it goes too high, the resulting image may be too gray and hard to interpret. Values far below 50 kV often fail to penetrate adequately, while very high values (approaching 150–250 kV) are not standard for most routine exams because they diminish contrast too much. So, approximately 50–120 kV is the practical range used to balance penetration, image quality, and patient dose across common diagnostic procedures.