Answer to Question #1832 Submitted to "Ask the Experts"

Category: Doses and Dose Calculations — Basic dose information, dose quantities, units

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

I'm trying to develop/calculate an analogy to compare exposure received from an x ray (say 300 mrem) to exposure rate imparted to a NORM worker. Are the following calculations correct? X ray exposure/time = 300 mrem/.04 sec = 7,500,000 microR. For a NORM Worker to receive that exposure he would need to be exposed to a rate of: 7,500,000 microR/2,080 hr = 3,605 microR/hr. . . . where 52 weeks/yr x 40 hrs/wk = 2,080 hrs

There are some problems with your calculations. Based on the information given I say:

The total effective dose (ED) from the procedure is 300 mrem, independent of delivery time (perhaps a GI series). The constant effective dose rate to be received by a NORM worker to equal this ED would be simply:

300 mrem/2,080 h = 0.14 mrem/hour.

John Lowe

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