Calculation of the Inactivation Cross Section of V79 Cells by Protons in Radiotherapy

Faika A Azooz, Thamer J Alkhalidy


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 μm2). 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. 


Radiotherapy; Inactivation cross section; DNA damage; Mean free path; Ionisation, specific primary; Energy transfer, linear.

Full Text:



  • There are currently no refbacks.

Creative Commons License
This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.

Sultan Qaboos University Medical Journal, College of Medicine and Health Sciences, Sultan Qaboos University, PO Box 35, Postal Code 123, Al-Khod, Muscat, Oman

ISSN (Print edition): 2075-051X ISSN (Internet edition): 2075-0528

Copyright SQUMJ 2019. This journal and its content is licensed under a Creative Commons Attribution No Derivatives 4.0 International license.

Flag Counter