1. For each single year of age (column 1 in the spreadsheet), the sex-specific estimated numbers of lifetime excess thyroid cancer cases in the US due to NTS fallout (columns 8 and 9) were obtained as the product of:

  • the number of male or female persons in the 1952 US population (columns 2 and 3)

  • the age-specific estimated average cumulative thyroid dose over the entire period of above-ground testing (column 4)

  • the age-specific linear dose-response coefficient (ERR at 1 rad) for x ray and gamma ray (column 5), times the assumed RBE for 131I

  • the cumulative lifetime thyroid cancer risk for men or women (0.25% or 0.64%), as appropriate.

  1. The age and sex-specific totals were summed over sexes (column 10) and ages. The sums are given below columns 8-10 in each table.

  2. Besides uncertainty about the RBE, there is also statistical uncertainty about the risk coefficients, and subjective and statistical uncertainty about the average doses used. The combined uncertainty is substantial. For example:

    • 95% confidence limits (2.1-28.7) for the Ron estimate of ERR1Gy = 7.7 correspond approximately to a lognormal model geometric standard deviation (GSD) of about 1.95.

    • The uncertainty of average dose estimated by the NCI, 2 rad, was stated to be between 1 and 4, i.e., a factor of 2 in each direction. This corresponds approximately to 95% confidence limits and thus to a GSD of about 1.4.

    • Therefore, the product of that dose and the estimated ERR at 1 rad has a GSD of 2.1 (calculated as the exponential of the square root of the sum of squares of the natural logarithms of 1.95 and 1.4).

    • Approximate 95% confidence limits for the number of excess cases can be obtained by dividing and multiplying by 4.3 (=2.11.96). Thus, for example, ignoring all other possible sources of error, an estimate of 49,000 lifetime excess cases (corresponding to a fixed RBE of 0.66, which here is assumed to be known without error) might be given with uncertainty 11,300-212,000.



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