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8
Recommendations
A. REPORTING OF BIAS AND UNCERTAINTY
For each test series, this report lists the best estimate of the overall bias, B. for
correcting film badge readings and converting them to deep-dose equivalents. It
also lists the best estimate of the uncertainty, K, which quantifies the range of
uncertainty at the 95% confidence level for these bias-adjusted values. Values
assigned to both B and K take into account the specific exposure conditions and
sources of uncertainty for each series. To obtain the best estimate of the deem
dose equivalent in rem, the reported film badge exposure in R is divided by the
overall bias, B. To obtain the upper and lower limits of uncertainty at the 95%
confidence level, this calculated best estimate of the deep-dose equivalent is
multiplied by K and divided by K, respectively. The Committee recommends that
these calculations be performed for each reported exposure under investigation.
Tables for converting reported individual film badge exposures are provided for
each test series in Chapter 6.
B. TREATMENT OF EXPOSURES REPORTED AS BELOW
MINIlVIUlV! DETECTABLE LEVELS OR AS ZERO
The general recommendation of the Committee in circumstances where a large
number of readings below the minimum detectable level (MDL) appear in a
participant's record, or where the MDL is unusually high, due to unusual environ-
mental circumstances, is to allot one-half of the MDL for each zero appearing in
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192
FILM BADGE DOSIMETRY mr ATMOSPHERIC NUCLEAR TESTS
the record (Section 5.C). For consistency, recorded film badge readings below
the MDL also should be interpreted as one-half the MDL, since, in fact, these
readings are not distinguishable from zero. A review of the e~osure-reading
distribution for all test series leads the Committee to conclude that such a practice
would probably overestimate the actual exposure, but that it would not greatly
exaggerate the general results in any test series or the recorded exposure of any
single participant. In special circumstances such as when the overwhelming
majority of readings for a group of participants similarly exposed during a given
exposure period were zero, zero is probably the reading of choice in terms of
maximum accuracy and should be used accordingly.
The Committee emphasizes that this treatment of reported exposures below the
MDL for assessment purposes is suggested only in individual cases where there is
reason to investigate possible biological effects attributable to the radiation dose.
It does not recommend changes to existing records.
C. UNCERTAINTIES IN THE SUMMATION OF SEVERAL FILM
BADGE READINGS
Determination of an individual's total deep-dose equivalent will often require
the summation of deep-dose equivalents obtained from more than one film badge
reading. For this total, the upper and lower confidence limits can be estimated by
summing the upper and lower 95% confidence limits for the individual assess-
ments of deep-dose equivalent. It should be noted that this procedure will over-
esiimate the range of uncertainty at the 95% confidence level.
Representative terms from entire chapter:
test series
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