The biological effectiveness of radon-progeny alpha particles. IV. Morphological transformation of Syrian hamster embryo cells at low doses
- College of Physicians and Surgeons of Columbia Univ., New York, NY (United States); and others
Primary explants of Syrian hamster embryo (SHE) cells were exposed to either low-LET 250 k Vp X rays or graded single doses of defined high-LET {alpha} particles (90, 100, 120, 150, 180 and 200 keV/{mu}m), simulating those produced by radon progeny, and monitored for cell inactivation and oncogenic transformation. For the {alpha} particles the doses delivered ranged from 1 cGy to 1 Gy with an emphasis on doses less than 20 cGy, while for the X rays the doses ranged from 20 cGy to 4 Gy. The dose-response curves for cell killing by {alpha} particles approximated an exponential function of dose, whereas the X rays produced a curve with a shoulder characteristic of linear-quadratic relationships seen for low-LET radiations. The RBE at 10% survival varied between 3.6-7.0 depending on the LET of the {alpha} particles, with the RBE{sub m} ranging between 7-12. THe most effective {alpha} particles were those with an LET of 120 keV/{mu}m. All radiations produced initial increases in the frequency of morphological transformants, as a function of dose, with a rise to a maximum followed by a plateau in the response which was relatively constant at approximately 2-6 x 10{sup -3} transformants per initial cell at risk. At higher doses the transformation frequency, expressed per initial cell at risk, had a tendency to decline to parallel the cell survival response. Both the dose at which the maximum frequency of transformants were expressed and the initial slope of the dose-response relationship differed substantially between the different radiation qualities. Maximal transformation per initial cell at risk occurred at doses as low as 1-4 cGy for the 90 and 100 keV/{mu}m particles with the maximum occurring at higher doses (to 16 cGy) as the LET increased toward 200 keV/{mu}m. In contrast, the maximal transformation for 250 kVp X rays was at 50 cGy. 35 refs., 6 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-88ER60631
- OSTI ID:
- 86333
- Journal Information:
- Radiation Research, Vol. 142, Issue 1; Other Information: PBD: Apr 1995
- Country of Publication:
- United States
- Language:
- English
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