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

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

Answer: (B)

Kilovoltage peak sets the energy of the X-ray photons and shapes both penetration and image contrast in diagnostic imaging. The practical range used to handle a variety of body parts is about 50 to 120 kilovolts. This span lets you tailor technique: lower kVp around 50–70 for thinner parts to maximize contrast, and higher kVp around 90–120 for thicker areas like the chest or abdomen to ensure enough penetration. Choosing too low a kVp would fail to penetrate larger tissues, and going well above 120 tends to reduce image contrast without a proportional diagnostic benefit. So, 50–120 kV covers the typical diagnostic needs across most exam scenarios.