Abstract
Purpose
The effect of chronic low dose-rate radiation exposure on cancers was investigated by analyzing the data of mice experiments conducted at the Institute for Environmental Sciences (IES). This analysis focuses on the differences between malignant lymphomas and solid cancers.
Materials and methods
The analysis is conducted based on the mathematical model introduced in our previous work. The model is expanded to analyze malignant lymphomas and solid cancers separately. Using the expanded model, the effect of chronic low dose-rate radiation on malignant lymphomas and solid cancers are discussed based on their occurrences, progressions, and mortalities.
Results
Non-irradiated control group and 20 mGy/day × 400 days irradiated groups are analyzed. The analysis showed that radiation exposure shortened mean life expectancy for both malignant lymphomas and solid cancers (shorter by 89.6 days for malignant lymphomas and 149.3 days for solid cancers). For malignant lymphomas, both the occurrence and the progression are affected by radiation exposure. The mean age at which malignant lymphoma developed in mice was shortened by 32.7 days and the mean progression period was shortened by 57.3 days. The occurrence of solid cancer is also affected by radiation exposure, wherein the mean age at which solid cancer develops was shortened by 147.9 days. However, no significant change in progression period of solid cancers was seen in the analysis.
Conclusions
The analysis showed that the occurrence and mean lifespan are affected in both malignant lymphomas and solid cancers. The shortening of the progression period is only seen in malignant lymphoma, no significant change was observed in solid cancers.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Additional information
Funding
Notes on contributors
Tetsuhiro Kinugawa
Tetsuhiro Kinugawa is a Ph.D. student in Graduate School of Engineering, Osaka University. His research topic is mathematical analysis of biological effects caused by radiation.
Ignacia Braga Tanaka
Ignacia Braga Tanaka III, DVM, Ph.D. is a Senior Researcher in Department of Radiobiology at the Institute for Environmental Sciences. Her research interests are mainly on pathology of the biological effects of low dose-rate radiation exposure.
Satoshi Tanaka
Satoshi Tanaka, DVM, Ph.D. is a Senior Researcher in Department of Radiobiology at the Institute for Environmental Sciences. His research interests are mainly on pathology of the biological effects of low dose-rate radiation exposure.
Yuichiro Manabe
Yuichiro Manabe, Assistant Professor, Doctor of Sciences (theoretical nuclear physics), is representative of interdisciplinary platform for biological effect of radiation, Collaborative Research Projects, Graduate School of Engineering, Osaka University. His research topics are simple mathematical model which give account to biological effects caused by radiation.
Fuminobu Sato
Fuminobu Sato, Ph.D. is a Professor of Graduate School of Engineering, Osaka University. His research focuses on nuclear reactor decommissioning.
Takahiro Wada
Takahiro Wada, Ph.D., is a Professor of Faculty of Engineering Science, Kansai University. His research interests lie in theoretical nuclear physics, especially the fluctuation-dissipation dynamics of nuclear fission and in mathematical model analysis of the biological effects of radiation.