The inverse dose-rate effect for oncogenic transformation by charged particles is dependent on linear energy transfer.
Mouse C3H 10T1/2 cells were exposed to single or fractionated doses of charged particles of defined linear energy transfer (LET) from 25 to 200 keV/microns. Dose fractionation with prolonged time intervals enhanced the yield of transformed foci compared with a single acute dose for a range of LET values between 40 and 120 keV/microns. Radiations of lower or higher LET did not show the enhancement that is commonly referred to as the inverse dose-rate effect. The fractionation scheme that was used consisted of three dose fractions; the maximum enhancement of transformation occurred with an interval of 150 min between dose fractions. This inverse dose-rate effect, demonstrated for cycling cells in log phase, was not seen for cells in plateau phase.
Miller
R C
RC
Center for Radiological Research, College of Physicians and Surgeons of Columbia University, New York, New York 10032.
Randers-Pehrson
G
G
Hieber
L
L
Marino
S A
SA
Richards
M
M
Hall
E J
EJ
D000818:Animals; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000528:radiation effects*; D003903:Deuterium; D004307:Dose-Response Relationship, Radiation; D004735:Energy Transfer; D006371:Helium; D007554:Isotopes; D051379:Mice; D008809:Mice, Inbred C3H
D007554:Isotopes; D006371:Helium; D003903:Deuterium