How this calculator works
Typical adult doses vary substantially with technique, equipment, anatomy and protocol. The presets are the published UK patient-dose guidance, rather than patient-specific measurements. Use a supplied effective dose when an appropriate estimate is available. Exams not listed require a custom value; procedure names alone cannot establish their dose. Effective dose is a population-weighted protection quantity and must not be read as an individual organ dose, absorbed dose or personal cancer probability. UK source data are used under the Open Government Licence v3.0. The result is an estimate for information only and is not medical advice.
Formula
Total effective dose (mSv) = exam count x dose per exam (mSv). Exam-count equivalent = total/dose per exam. Sv = mSv/1000; mrem = mSv x 100. Counts of actual examinations must be non-negative integers.
Worked example
The UK reference gives 0.02 mSv for one single-PA chest film. Five such exams give 0.10 mSv, or 0.0001 Sv and 10 mrem. Two CT head exams at the 2 mSv reference give 4 mSv.
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Frequently asked questions
Why does another source give a different chest dose?
A single PA film differs from a two-view chest examination, and reference doses also vary by technique and source. Use the matching exam description.
Can this calculate an individual cancer risk?
No. Effective dose supports broad comparisons and protection planning. Personal risk depends on age, exposed organs, dose distribution and many other factors.
What if my procedure is not listed?
Use the custom option with a justified effective dose in mSv. The calculator does not guess dose values for unverified procedures.