Dosimetry System 1986 (DS86)

In the late 1970s, scientists from the United States noticed differences between the T65D doses, extensively used in the study of radiation hazards among atomic-bomb (A-bomb) survivors, and the theoretical dose estimates. Therefore, a US-Japan joint study was initiated to reassess various factors related to the A-bomb explosions that determine actual doses of ionizing radiation. The new dosimetry system, Dosimetry System 1986, was established in March 1986. DS86 permits the calculating of exposures received by various organs (referred to as organ doses) on the basis of individual exposure-history information, something that could not be done with the T65D system. Using DS86, the dose-response relationships of the various effects resulting from A-bomb radiation exposure were reassessed. Further refinement of DS86, ultimately replaced by DS02, was continued over several years.

A total dose (in gray) of gamma and neutron radiations is assigned to an individual. See the Table, which shows the free-in-air dose (kerma) of gamma rays.