The oncogenic risk of alpha doses from osteotropic radionuclides down to the milliGray range and the role of the reverse protraction factor
In a twenty-five year series of animal experiments skeletal doses between 0.15 - 20 Gy of the short-lived radium isotope 224Ra (half-life 3.6 days) were applied to more than one thousand mice (mostly female NMRI). The dose rate was varied in an even wider range, from 0.0011 Gy/d to 4.32 Gy/d, by applying single and protracted injections. The injection schedule included irradiation periods from about two weeks (single injections) up to 9 months. Analysis of the results showed that protracted alpha doses are more effective than single doses with respect to osteosarcoma induction in the higher dose ranges (above 100 cGy). It was also seen that when extrapolating radiogenic effects to very low doses, it is necessary to consider both quantitative aspects and also changes in the spectrum of tumours induced.
Bibliographic Reference: Paper presented: Joint Bone Workshop, Toronto (CA), July 12-13, 1991
Availability: Available from (1) as Paper EN 37295 ORA
Record Number: 199310638 / Last updated on: 1994-11-29
Original language: en
Available languages: en