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Fission fragment relative biological effectiveness for liver tumor induction
G N Taylor1, R D Lloyd, C W Mays
1Radiobiology Laboratory, University of Utah, Salt Lake City 84112, USA.
Health Physics
|August 1, 1995
Summary
Fission fragments from Californium-249 or Californium-252 may be more effective at causing liver tumors than alpha particles. This study in beagles suggests a higher relative biological effectiveness for liver neoplasia than for bone cancer.
Area of Science:
- Radiobiology
- Nuclear Medicine
- Oncology
Background:
- Assessing the biological impact of radioactive isotopes is crucial for radiation safety and medical applications.
- Californium isotopes (Cf) emit alpha particles and spontaneous fission fragments, necessitating distinct biological effectiveness evaluations.
- Liver tumors and bone cancers are significant endpoints for evaluating radiation-induced carcinogenesis.
Purpose of the Study:
- To determine the relative biological effectiveness (RBE) of Californium fission fragments compared to alpha particles.
- To investigate the RBE for liver neoplasia and bone cancer endpoints.
- To provide data for risk assessment of Californium radioisotopes.
Main Methods:
- Utilized risk coefficients derived from 60 beagles with body burdens of Californium-249 or Californium-252.
- Calculated the RBE of fission fragments relative to alpha particles for liver malignancies.
- Analyzed data for both benign and malignant liver tumors, as well as bone cancer incidence.
Main Results:
- The RBE for liver malignancies was calculated as approximately 2 +/- 3.
- Estimates based on combined benign and malignant liver tumors yielded an RBE of about 7 +/- 14.
- The RBE for bone cancer was found to be only slightly above zero.
Conclusions:
- The RBE of fission fragments relative to alpha particles for liver neoplasia may be greater than 1.0.
- Confidence intervals for RBE estimates were wide, indicating uncertainty.
- Fission fragments appear to pose a greater risk for liver tumors than for bone cancer compared to alpha particles.

