Basic Clinical Radiobiology 2017

Summary: Radiation 1 • Radiation carcinogenesis is a stochastic effect

• Human experience includes early workers exposed occupationally, patients exposed to medical irradiation , survivors of A-bomb attacks on Hiroshima and Nagasaki, and Chernobyl • Shortest latency is for leukemia, which peaks at 5 to 7 years. For solid tumours, latency may extend to > 60 years • Radiation-induced cancer risks are usually based on a time-related Relative Risk (RR) model • A dose and dose-rate effectiveness factor (DDREF) converts risk estimates from acute exposures ( e.g. A-bomb data) to the low dose and low dose rates encountered in radiation protection. ICRP conservatively assumes DDREF = 2