title: Effect of dose-rate on induction of neoplastic transformation in vitro by low doses of 232 MeV protons.
abstract: OBJECTIVE
  To determine the effect of dose-rate on induction of neoplastic transformation in vitro by low doses of 232 MeV protons.
  
  
  METHODS
  The experimental system used was the human hybrid cell assay. The dose-rates examined were 50 cGy/min and 20 cGy/h. The dose-rate 20 cGy/h was chosen as this is in the range of the maximum dose-rate that can be experienced in an unshielded space environment following a solar flare. At low dose-rate (LDR), doses from 0.5-100 cGy were studied. At high dose rate (HDR), the dose range was 0.5-200 cGy.
  
  
  RESULTS
  The data indicated no significant differences between the two dose-rates at doses up to 100 cGy.
  
  
  CONCLUSIONS
  For the endpoint of neoplastic transformation in vitro, high dose-rate data may be sufficient to estimate low dose-rate effects (20 cGy/h) in the dose range up to 100 cGy from 232 MeV protons. The data are of relevance to risk estimation for space travel.
authors.affiliation: Department of Radiation Oncology, School of Medicine, University of California Irvine, Irvine, CA 92697, USA.
authors.forename: Eugene
authors.initials: E
authors.lastname: Elmore
authors.forename: Xyoan Y
authors.initials: XY
authors.lastname: Lao
authors.forename: Rubina L
authors.initials: RL
authors.lastname: Kapadia
authors.forename: J Leslie
authors.initials: JL
authors.lastname: Redpath
mesh_terms: D002471:Cell Transformation, Neoplastic; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000166:cytology / Q000528:radiation effects; D006367:HeLa Cells; D006801:Humans; D006822:Hybrid Cells; D018499:Linear Energy Transfer; D009369:Neoplasms / Q000473:pathology*; D009381:Neoplasms, Radiation-Induced / Q000473:pathology; D011522:Protons; D011829:Radiation Dosage; D012306:Risk; D019445:Solar Activity
chemical_list: D011522:Protons