The average film badge dose measurement accuracy is approximately what percent?

• A. ±1%
• B. ±9%
• C. ±25%
• D. ±40%

Answer: (C)

Film badge dosimetry has more variability than newer dosimetry methods because the measurement depends on the optical density of exposed film, which is influenced by processing conditions, film batch, energy of the radiation, and the calibration between dose and density. These factors introduce a level of uncertainty that commonly results in about a quarter of the delivered dose being off on average. In practical terms, you’d expect roughly ±25% accuracy for an average film badge reading, reflecting the combined effects of processing differences, energy dependence, and reading/calibration variability.

The tighter options (±1% and ±9%) are not realistic given the inherent fluctuations in film processing and reader calibration, while a much larger margin like ±40% would overstate the precision issues in most typical clinical settings.