Answer to Question #13084 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment/Shielding — Equipment

The following question was answered by an expert in the appropriate field:

Q

I am trying to calculate the effective dose from a fluoroscopy procedure. I have the cumulative air kerma from the fluoroscopy procedure to effective dose. Can you recommend methods to do the calculation?

A

In angiography and interventional radiology, the effective dose (E) is estimated by multiplying the kerma area product (KAP) or dose area product (DAP) and a specific conversion coefficient (CC).

The KAP is simply average air kerma (in Gy) multiplied by the corresponding x-ray beam cross-sectional area (in cm2), the product of which being expressed as Gy · cm2.

 So, E (mSv) =  KAP (Gy · cm2) x CC (mSv Gy-1 · cm-2)) .

Coefficients for various procedures can be found in published tables. Good sources for CC are Hart et al. (1994) and Drexler et al. (1990).

Terry Yoshizumi, PhD, FAAPM, DABR, DABSNM, DABMP

References

Hart D, Jones DG, Wall BF. Estimation of effective dose in diagnostic radiology from entrance surface dose and dose-area product measurements. NRPB-R262 Chilton: NRPB; 1994. Accessed 30 September 2019.

Drexler G, Panzer W, Widenmann L, Williams G, Zankl M. The calculation of dose from external photon exposures using reference human phantoms and Monte-Carlo methods, part III: organ doses in x-ray diagnosis. GSF Report 11/90. Neuherberg: National Centre for Environment and Health 1–60; 1990.

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