OBJECTIVE: For efficient applications of protons in radiotherapy, detailed knowledge of the corresponding radiobiological mechanism is necessary. The inactivation cross section is a useful tool to explore the interaction mechanism. Hence, the inactivation cross section for proton irradiation on V79 cells has been calculated using published survival data. METHOD: The linear quadratic equation was used to fit the survival curves and the parameter α was used to calculate the cross section. The cross section σ is plotted as a function of the mean free path λ and the linear energy transfer LET. RESULTS: The cross section σ-versus-λ curve shows a saturation region between λ≥2 nm and λ≤5 nm. In this region, the inactivation cross section value is about the same as the geometrical area of the DNA segment (≈4 μm(2)). Such a saturation is also seen in the σ-LET curve. CONCLUSION: This implies that one DNA segment is at a risk upon the traversal of a single proton.
OBJECTIVE: For efficient applications of protons in radiotherapy, detailed knowledge of the corresponding radiobiological mechanism is necessary. The inactivation cross section is a useful tool to explore the interaction mechanism. Hence, the inactivation cross section for proton irradiation on V79 cells has been calculated using published survival data. METHOD: The linear quadratic equation was used to fit the survival curves and the parameter α was used to calculate the cross section. The cross section σ is plotted as a function of the mean free path λ and the linear energy transfer LET. RESULTS: The cross section σ-versus-λ curve shows a saturation region between λ≥2 nm and λ≤5 nm. In this region, the inactivation cross section value is about the same as the geometrical area of the DNA segment (≈4 μm(2)). Such a saturation is also seen in the σ-LET curve. CONCLUSION: This implies that one DNA segment is at a risk upon the traversal of a single proton.
Keywords:
DNA damage; Energy transfer, linear; Inactivation cross section; Ionisation, specific primary; Mean free path; Radiotherapy
Authors: D T Goodhead; M Belli; A J Mill; D A Bance; L A Allen; S C Hall; F Ianzani; G Simone; D L Stevens; A Stretch Journal: Int J Radiat Biol Date: 1992-05 Impact factor: 2.694
Authors: M Belli; F Cera; R Cherubini; M Dalla Vecchia; A M Haque; F Ianzini; G Moschini; O Sapora; G Simone; M A Tabocchini; P Tiveron Journal: Int J Radiat Biol Date: 1998-10 Impact factor: 2.694
Authors: M Belli; F Cera; R Cherubini; A M Haque; F Ianzini; G Moschini; O Sapora; G Simone; M A Tabocchini; P Tiveron Journal: Int J Radiat Biol Date: 1993-03 Impact factor: 2.694