Question

What lessens the A-bomb droppers' burden of
conscience?​

Answer 1

Explanation:

Excess leukemia was the earliest delayed effect of radiation exposure seen in A-bomb survivors. Japanese physician Takuso Yamawaki in Hiroshima first noted an increase of leukemia cases in his clinical practice in the late 1940s. This led to the establishment of a registry of leukemia and related disorders and to the initial reports on elevated leukemia risks published in the early 1950s.

Risks for radiation-induced leukemia differ in two major respects from those for most solid cancers. First, radiation causes a larger percent increase in leukemia rates (but a smaller number of cases since leukemia is relatively rare, even in heavily exposed survivors), and second, the increase appears sooner after exposure, especially in children. The excess leukemias began appearing about two years after radiation exposure, and the excess peaked at about 6-8 years after exposure. Today, little if any excess of leukemia is occurring.

Because the Life Span Study(LSS) cohort was based on the 1950 national census, quantitative descriptions of leukemia risks in A-bomb survivors have been based on cases diagnosed from that year on. As of the year 2000, there were 204 leukemia deaths among 49,204 LSS survivors with a bone marrow dose of at least 0.005 Gy, an excess of 94 cases (46%) attributable to A-bomb radiation (Table). In contrast to dose-response patterns for other cancers, that for leukemia appears to be nonlinear; low doses may be less effective than would