Which statement best describes acceptable exposure index values in radiography?

• A. Higher index always improves image quality
• B. Index values within the recommended range indicate acceptable exposure
• C. Index must be at mid-range
• D. Index values have no relation to dose

Answer: (B)

Exposure index shows how much radiation actually reached the image receptor. When that index falls within the system’s recommended range, it generally means the exposure was appropriate for the patient and the exam, delivering enough photons to produce a usable image while avoiding unnecessary dose. Image quality comes from more than just the index—factors like kVp, mAs, beam geometry, and patient size all play roles—so a higher index doesn’t automatically mean a better image. Conversely, a value below the recommended range can lead to underexposure and a noisy image, while a value above it can mean overexposure and higher patient dose. Each system defines its target and acceptable window, and staying within that range indicates acceptable exposure.