title: Dose-response effect of charged carbon beam on normal rat retina assessed by electroretinography.
abstract: OBJECTIVE
  To compare the effects of carbon beam irradiation with those of proton beam irradiation on the physiology of the retina of rats.
  
  
  METHODS
  Eight-week-old Wister rats were used. The right eyes were irradiated with carbon beam (1, 2, 4, 8, and 16 Gy) or proton beam (4, 8, 16, and 24 Gy) with the rats under general anesthesia. Electroretinograms were recorded 1, 3, 6, and 12 months after the irradiation, and the amplitudes of the a and b waves were compared with those of control rats.
  
  
  RESULTS
  The amplitude of b waves was reduced more than that of a waves at lower irradiation doses with both types of irradiation. With carbon ion irradiation, the amplitudes of the b wave were significantly reduced after radiation doses of 8 and 16 Gy at 6 months and by radiation doses of 4, 8, and 16 Gy at 12 months. With proton beam irradiation, the b-wave amplitudes were significantly reduced after 16 and 24 Gy at 6 months and with doses of 8 Gy or greater at 12 months. For the maximum b-wave amplitude, a significant difference was observed in rats irradiated with carbon beams of 4 Gy or more and with proton beams of 8 Gy or more at 12 months after irradiation.
  
  
  CONCLUSIONS
  These results indicate that carbon beam irradiation is about two times more damaging than proton beam irradiation on the rat retina at the same dose.
authors.affiliation: Department of Ophthalmology, Teikyo University School of Medicine, Tokyo, Japan. mizota-a@med.teikyo-u.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Mizota
authors.forename: Minoru
authors.initials: M
authors.lastname: Tanaka
authors.forename: Mariko
authors.initials: M
authors.lastname: Kubota
authors.forename: Hisanari
authors.initials: H
authors.lastname: Negishi
authors.forename: Emiko
authors.initials: E
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuji
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Miyahara
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Furusawa
mesh_terms: D000818:Animals; D002250:Carbon Radioisotopes / Q000494:pharmacology*; D004307:Dose-Response Relationship, Radiation; D004596:Electroretinography; D005260:Female; D061766:Proton Therapy; D011833:Radiation Injuries, Experimental / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000502:physiology / Q000528:radiation effects*; D013997:Time Factors
chemical_list: D002250:Carbon Radioisotopes