ABS 048: X-rays Interaction and Characterization of Blood, Breast, Eye Lens, Ovary, and Testis, using Klein-Nishina Formula

Muhammad Maqbool ¹ , Jia Ali ¹ , Elise Kapshtica ¹ , Madhesh Raja ¹ , Daniel Banks ¹ , Sami Raja ¹

¹ Department of Clinical and Diagnostics, School of Health Professions

Van Wickle (2025) Volume 1, ABS 048

Introduction: We study the interaction of X-rays of energies ranging from 0.1 MeV up to 20 MeV with various body tissues and calculate their electronic and atomic, cross-sections, and Compton mass attenuation coefficients. An optimum and precise dose delivery is important in radiation oncology and radiology, as it's not only required for the best treatment outcomes, but also the safety and protection of normal tissues. To understand and calculate the correct dose, one must study the interaction of radiation with various tissues of the body. We use the Klein-Nishina formula to calculate the electronic and atomic cross-sections, as well as the Compton mass attenuation coefficient. We found that the calculated parameters for blood, breasts, eye lens, ovaries, and testis are dependent on the energy of X-rays, effective charge number of tissues, and density of tissues.

Methods: This study examines how X-rays with energies from 0.1 to 20 MeV interact with Blood, Breast, Eye Lens, Ovary, and Testis tissues. The analysis involves calculating the Klein-Nishina electronic cross-section, atomic cross-section, and Compton mass-attenuation coefficient. The Klein-Nishina formula estimates the electronic cross-section by modeling photon scattering off free electrons. The atomic cross-section is then derived by multiplying the electronic cross-section with the tissue's effective atomic number (Z). Finally, the Compton mass-attenuation coefficient, which indicates how X-rays are attenuated per unit mass due to Compton scattering, is computed using the relation: σ/ρ = (NₐZ/A)·σₑ, where Nₐ is Avogadro’s number and A is the average atomic mass. These calculations help assess how different tissues absorb or scatter X-rays, depending on their composition and density, which is vital for medical imaging and radiation protection studies.

Results: We have demonstrated that increasing X-ray energy from 0.1–20 MeV leads to a decrease in the Klein-Nishina electronic and atomic cross-sections, indicating reduced photon-tissue interaction at higher energies. Atomic cross-sections increase with tissue density due to a higher number of electrons. The Compton mass-attenuation coefficient rises sharply with increasing Z/A ratios before stabilizing, reflecting enhanced scattering in high-Z tissues. Variations in effective atomic number introduce complexity due to competing effects of photoelectric absorption and Compton scattering. These findings confirm that photon energy, atomic structure, and density collectively influence radiation interaction with biological tissues.

Discuss: Our findings highlight the critical role of tissue composition—specifically effective atomic number and density—in determining X-ray interaction through Compton scattering. This has significant implications for radiation therapy, diagnostic imaging, and radiation protection, particularly in optimizing dose delivery and minimizing exposure to sensitive tissues. The observed dependence of mass-attenuation on Z/A ratios suggests potential for tissue-specific imaging and improved material differentiation. Future research should explore these relationships across broader biological models and integrate photoelectric effects at lower energies to enhance predictive accuracy in clinical and radiological applications.