of the study's results. Then there is a general description of the pathways of iodine-131 (I-131 or 131I) exposure in humans. Most of the chapter is devoted to a review of the NCI report, and specific comments are made about NCI's methods, their appropriateness, and their shortcomings.

Box 2.1 lists chapter contents from Volume 1 of the NCI report and the appendices of Volume 2. Separate from the published report, NCI staff prepared estimates of the number of people who might be expected to develop fallout-related thyroid cancer (see Appendix B of this report). Additional information is also available on the NCI Web site (http://rex.nci.nih.gov).1

BASIC ASSESSMENT

Given the challenges posed by the paucity of the data relevant to dose reconstruction, the disparity between the original purpose of the data collection and the requirements for dose reconstruction, the need to derive amounts of I-131 ingested on the basis of measured deposition of gross beta activity, and the problems associated with drawing conclusions about counties and states based on incomplete information, this committee was generally impressed by the clarity and thoroughness of the NCI report and the obvious attention to detail. This committee does note, however, that some of the procedures used in dose reconstruction were not sufficiently detailed (for example, the discussion of kriging) for the committee to judge fully the efficacy of NCI's work and the accuracy of the results. The task confronting the NCI investigators was obviously formidable, requiring the reconstruction of events—some of which occurred almost a half-century ago—for which direct measurements of dose or even environmental contamination were often limited or nonexistent, particularly in areas of the continental United States not immediately adjacent to the Nevada Test Site.

There is an important way in which the presentation of NCI's findings is inadequate. The report gives very little statistical tabulation of dose estimates that is useful from a scientific or epidemiologic standpoint. The important numbers, averaged dose by birth cohort, used in the Land presentation, for example, cannot be easily verified as being consistent with the report. The report, the annexes, and Internet Web pages do not appear to allow for the ready computation of average doses for broad categories of people or for the uncertainties in those average doses. This makes it difficult to apply the findings of the report to compute, for example, doses for birth cohorts of people living in the regions covered by tumor registries in two different states or cities, as would be needed in the design stages of an epidemiologic analysis. The numbers provided in the map captions could be used to tabulate average dose by birth cohort, for example, but it would be laborious and possibly inaccurate to use the maps to do this by region. The report and

1  

To find information on the 1997 NCI report, it is necessary to follow on-screen links at the NCI Web site to "What Was New in 1997?"



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