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Updated: Feb 13, 2026
06:08
Use of a Linear Accelerator for Conducting In Vitro Radiobiology Experiments
Published on: May 26, 2019
8.0K
Monte Carlo studies on photon interactions in radiobiological experiments.
Mehrdad Shahmohammadi Beni1, D Krstic2, D Nikezic1,2
1Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong.
Plos One
|March 22, 2018
Summary
This study investigates how X-ray and gamma-ray photons interact in radiobiology. Understanding photon interactions and electron hits is crucial for explaining radiation dose thresholds and cancer detection limits.
Area of Science:
- Medical Physics
- Radiation Biology
- Computational Physics
Background:
- X-ray and gamma-ray photons are indirectly ionizing radiations used in radiobiology.
- Photon interactions necessitate electron release for ionization, impacting cellular exposure.
- Low photon doses can lead to non-uniform cellular electron hits, causing rescue effects.
Purpose of the Study:
- To investigate the mechanisms of photon interactions in radiobiological experiments.
- To analyze the factors influencing electron ejection and cellular hits by photons.
- To benchmark the NRUphoton code against MCNP5 for photon dose calculations.
Main Methods:
- Utilized the developed NRUphoton computer code for simulating photon interactions.
- Benchmarked NRUphoton against the MCNP5 code for photon dose calculations.
- Analyzed interaction fractions, electron ejection, penetration, and angular distributions.
Main Results:
- Interaction fractions followed the order: 16O > 12C > 14N > 1H.
- Photoelectric effect dominated low-energy photons (10 keV), while incoherent scattering dominated high-energy photons (100 keV, 1 MeV).
- Electron ejection fractions were highest from the 1s subshell, governed by photoelectric cross-sections.
- Penetration fractions decreased with medium thickness and increased with photon energy.
- Fewer cells received electron hits at higher photon energies due to reduced interaction cross-sections.
Conclusions:
- Photon interaction mechanisms and electron ejection are energy and material-dependent.
- The number of cells receiving at least one electron hit is dose-dependent.
- Findings may explain radiation dose thresholds for cancer detection and inform the linear no-threshold model debate.
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