Low dose hyper-radiosensitivity: A historical perspective

This chapter discusses the biology of low-dose hyper-radiosensitivity (HRS) with reference to radiation-induced DNA damage and cellular repair processes. Particular attention is paid to the significance of G2-phase cell cycle check-points in overcoming low-dose hyper-radiosensitivity and the impact of HRS on low-dose rate radiobiology. The history of HRS from the original in vivo discovery to the most recent in vitro and clinical data are examined to present a unifying hypothesis concerning the molecular control and regulation of this important low-dose radiation response. Finally, pre-clinical and clinical data are discussed, from a molecular viewpoint, to provide theoretical approaches to exploit HRS biology for clinical gain.