TY - JOUR
T1 - Neoplastic transformation in vitro induced by low doses of 232 MeV protons
AU - Elmore, E.
AU - Lao, X. Y.
AU - Ko, M.
AU - Rightnar, S.
AU - Nelson, G.
AU - Redpath, J. L.
N1 - Funding Information:
Support of DOE Grant No. FG-02-03ER63548 from the Low Dose Radiation Research Program is gratefully acknowledged. Protons were provided by the Loma Linda University Proton Treatment facility under funding by NASA Cooperative Agreement No. NCC9-149.
PY - 2005/4
Y1 - 2005/4
N2 - The aim was to define the dose-response curve for high-energy proton-induced neoplastic transformation in vitro. The HeLa × skin fibroblast human hybrid cell assay was used to determine the frequency of neoplastic transformation following doses of 232 MeV protons (mean linear energy transfer, LET = 0.44 keV μm-1) in the range 5-600 mGy. Proton irradiations were carried out at the Loma Linda University Proton Treatment Facility, CA, USA. The data indicate no evidence for induction of transformation below a dose of 100 mGy. At doses of 5 and 50 mGy, there is evidence for a possible suppression of transformation frequencies below that for spontaneous transformation. The shape of the dose - response curve for high-energy proton-induced transformation of the human hybrid cell line CGL1 does not follow a linear no-threshold model and shows evidence for a threshold as well as for possible suppression of transformation at doses < 100 mGy, similar to that seen for other low-LET radiations.
AB - The aim was to define the dose-response curve for high-energy proton-induced neoplastic transformation in vitro. The HeLa × skin fibroblast human hybrid cell assay was used to determine the frequency of neoplastic transformation following doses of 232 MeV protons (mean linear energy transfer, LET = 0.44 keV μm-1) in the range 5-600 mGy. Proton irradiations were carried out at the Loma Linda University Proton Treatment Facility, CA, USA. The data indicate no evidence for induction of transformation below a dose of 100 mGy. At doses of 5 and 50 mGy, there is evidence for a possible suppression of transformation frequencies below that for spontaneous transformation. The shape of the dose - response curve for high-energy proton-induced transformation of the human hybrid cell line CGL1 does not follow a linear no-threshold model and shows evidence for a threshold as well as for possible suppression of transformation at doses < 100 mGy, similar to that seen for other low-LET radiations.
KW - High energy protons
KW - Neoplastic transformation
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U2 - 10.1080/09553000500140324
DO - 10.1080/09553000500140324
M3 - Article
C2 - 16019938
SN - 0955-3002
VL - 81
SP - 291
EP - 297
JO - International Journal of Radiation Biology
JF - International Journal of Radiation Biology
IS - 4
ER -