Minimum Detectable Activity (MDA) calculations: Gamma Spectroscopy: At a 5% probability of making type I and type 2 errors,

MDA is the minimum detectable (quantifiable) activity in dpm at a specified confidence level. Additional conversion factors (C) may be applied to convert dpm to any other activity units that may be desired (e.g., μCi, kBq, etc.). MDA depends on the counting device, counting times (controllable by procedure) and background counting rate.

It is often advantageous to express the detection limit in the form of a minimum detectable activity. If the count rates and count times in Eq. (3) are expressed in CPM and minutes respectively, then the MDA is:

1996年7月10日 · It takes into account 5% type a (false detection) and 5% type b (missed detection) errors in both the background count and the gross count. The formula is good for any instrument and situation that produces counts, but as others have cautioned, the geometry has to be identical for both background and source measurements.

Determination of the Minimal Detectable Activity (MDA): Count the blank (background) for one minute. Calculate the MDA: SQRT (MDA (cpm) = 4.65 background (cpm)) To obtain results in dpm, divide the MDA by the efficiency. Record all calculations and results in the lab notebook with the monthly lab wipes.

Compare the MDA for two different systems by entering the efficiency (typical vs. typical or warranted vs. warranted) and background values for each individual system of interest. Protean Instrument provides an MDA calculator as a reference tool for estimating the MDAs that can be reached for various counting time.

2012年2月13日 · Determination of the minimum detectable activity (MDA) of a radionuclide being assessed through gamma ray spectrometry is more complicated than is the case for other common counting techniques.

2015年6月1日 · We have developed a numerical approach to calculating MDA values for radiation measurements which uses realistic statistical modeling to account for the effects of systematic uncertainties in the instrument calibration factors.

2022年8月24日 · In this paper, the MDA results of the recently implemented lognormal approximation algorithm are compared with those of the more exact numerical calculation using the same assumption of lognormal distribution of the calibration uncertainty, as well as with numerical calculations using several other physically plausible uncertainty models.

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