re aoe iy le vee? ve ' yn fie a Brn. gf ee ASSOCIATED UNIVERSITIES, INC. Upton, New York 11973 Safety & Environmental Protectan Division (516) 345- 4207 April 1, 1980 T.F. Division of Health and Environmental Research U. S. Department of Energy Washington, D. C. P, N . N. L. REPOS!TGRY McCraw 20545 COLLECTION Narshall ZF sia ” as (DOE) BOX No, . Dear Tom: 56 y¥7 tz FOLDER v In response to your question concerning the annual bone marrow dose equivalents, we have constructed Table 4 which lists those individuals whose red bone marrow dose equivalent exceeded 500 mRem in one year. In this table as with the annual total body dose equivalent table, one year is defined as the 12 consecutive months beginning September 1 and concluding August 31. During the year 1977 (9/1/76 to 8/31/77), 4 individuals exceeded the annual total body dose equivalent and 28 individuals exceeded the annual red bone marrow dose equivalent of 500 mRem in cne year. In the year 1978 (9/1/77 to 8/31/78), 22 individuals exceeded the annual total body dose equivalent and 49 individuals exceeded the annual red bone marrow dose equivalent of 500 mRem in one year. The higher number of persons who exceeded the annual dose equivalent to the red bone marrow is the result of the red bone marrow receiving a higher photon.dosa relative to most other tissues in the body. When absorbed into the blood, cesium is widely ciistributed among the body tissues, miscle having the highest concentration. Since muscle is widely distributed in the body, cesium is considered to irradiate the entire body. There is some buildup of the dose from photons in organs near the center of the trunk with smaller values of dose for organs near the surface. This variation is as much as a factor of two. Thus, there are individuals with annual total body dose equivalents less than 500 mRem in one year but with annual red bone marrow dose equivalents in excess uf 500 mRem in one year. DOCUMENT DOES NOT CONTAIN ECI Reviewed by Epohe,r) Date NS? If we can be of further service, please do not hesitate to contact Bob Miltenberger or Ed Lessard at FTS 666-2503, or me at 666-4250. cerely, . MC: At A. NAG/sle eer We. Robison 3. Wachholz Greenhouse