title: Inactivation of human cells exposed to fractionated doses of low energy protons: relationship between cell sensitivity and recovery efficiency.
abstract: Within the framework of radiation biophysics research in the hadrontherapy field, split-dose studies have been performed on four human cell lines with different radiation sensitivity (SCC25, HF19, H184B5 F5-1 M10, and SQ20B). Low energy protons of about 8 and 20 keV/micron LET and gamma-rays were used to study the relationship between the recovery ratio and the radiation quality. Each cell line was irradiated with two dose values corresponding to survival levels of about 5% and 1%. The same total dose was also delivered in two equal fractions separated by 1.5, 3, and 4.5 hours. A higher maximum recovery ratio was observed for radiosensitive cell lines as compared to radioresistant cells. The recovery potential after split doses was small for slow protons, compared to low-LET radiation. These data show that radiosensitivity may not be related to a deficient recovery, and suggest a possible involvement of inducible repair mechanisms.
authors.affiliation: Istituto Superiore di Sanità e Gruppo collegato Sanità INFN, Viale Regina Elena 299, I-00161 Roma, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Antonelli
authors.forename: D
authors.initials: D
authors.lastname: Bettega
authors.forename: P
authors.initials: P
authors.lastname: Calzolari
authors.forename: R
authors.initials: R
authors.lastname: Cherubini
authors.forename: M
authors.initials: M
authors.lastname: Dalla Vecchia
authors.forename: M
authors.initials: M
authors.lastname: Durante
authors.forename: S
authors.initials: S
authors.lastname: Favaretto
authors.forename: G
authors.initials: G
authors.lastname: Grossi
authors.forename: R
authors.initials: R
authors.lastname: Marchesini
authors.forename: M
authors.initials: M
authors.lastname: Pugliese
authors.forename: P
authors.initials: P
authors.lastname: Scampoli
authors.forename: G
authors.initials: G
authors.lastname: Simone
authors.forename: E
authors.initials: E
authors.lastname: Sorrentino
authors.forename: M A
authors.initials: MA
authors.lastname: Tabocchini
authors.forename: L
authors.initials: L
authors.lastname: Tallone
authors.forename: P
authors.initials: P
authors.lastname: Tiveron
mesh_terms: D002460:Cell Line; D002478:Cells, Cultured / Q000528:radiation effects*; D006801:Humans; D011522:Protons
chemical_list: D011522:Protons