Meta-analysis of non-tumour doses for radiation-induced cancer on the basis of dose-rate

Abstract

Purpose: Quantitative analysis of cancer risk of ionising radiation as a function of dose-rate.

Materials and methods: Non-tumour dose, D_nt, defined as the highest dose of radiation at which no statistically significant tumour increase was observed above the control level, was analysed as a function of dose-rate of radiation.

Results: An inverse correlation was found between D_nt and dose-rate of the radiation. D_nt increased 20-fold with decreasing dose-rate from 1–10⁻⁸ Gy/min for whole body irradiation with low linear energy transfer (LET) radiation. Partial body radiation also showed a dose-rate dependence with a 5- to 10-fold larger D_nt as dose rate decreased. The dose-rate effect was also found for high LET radiation but at 10-fold lower D_nt levels.

Conclusions: The cancer risk of ionising radiation varies 1000-fold depending on the dose-rate of radiation and exposure conditions. This analysis explains the discrepancy of cancer risk between A-bomb survivors and radium dial painters.

Keywords:

• radiation cancer risk
• non-tumour dose
• dose-rate

Acknowledgements

I thank Dr Kouichi Tatsumi, Radiation Effects Association, Dr Toshihiko Sado, National Institute of Radiological Sciences, and Dr Tomotaka Sobue, National Cancer Center, for useful discussions and suggestions, Dr Takahiro Ochiya, National Cancer Center, for support of this work, Dr Gerda Horneck, Institute of Aerospace Medicine, German Aeropace Center, Germany, for information on the radiation dose in space, Dr Bruce B. Boecker, Loveless Respiratory Research Institute, USA, for information on internal emitters, and Dr Maurice Tubiana, University of Paris, France, for providing me with valuable data prior to publishing.

Declaration of interest: The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.