title: A Logarithmic Formula to Describe the Relationship between the Increased Radiosensitivity at Low Doses and the Survival at 2 Gray.
abstract: OBJECTIVE
  Intrinsic radiosensitivity at doses used in radiotherapy is linked to hypersensitivity (HRS) and increased radio resistance (IRR) at low doses. The aim of this study was to explore this relationship.
  
  
  METHODS
  Survival curves for 18 human tumour cell lines were analysed, using two models to fit the data points in order to extract the necessary parameters relevant for this study.
  
  
  RESULTS
  The IRR ratio αs/αr versus the survival at 2 gray (Gy) can be described by a logarithmic relation which leads to a series of straight lines.
  
  
  CONCLUSIONS
  The relationship obtained implies that there is a direct link between HRS/IRR and survival at clinically relevant doses of 2 Gy.
authors.affiliation: Department of Physics, College of Education, University of Mosul, Mosul, Ninevah, Iraq.
authors.forename: Faika A
authors.initials: FA
authors.lastname: Azooz
authors.forename: Suzan K
authors.initials: SK
authors.lastname: Hashim
keywords: Analysis; Cell Line; Hypersensitivity, radiotherapy; Tumor