Photon Interaction Coefficients for the Colorectal Cancer Tissue

Emmanuel Okon Esien-Umo; Joseph Abebe Obu; Ndubuisi Ozoemena Chiaghanam; Theophilus Ipeh Ugbem; Nneoyi Onen Egbe

doi:10.4103/jmp.jmp_29_22

Photon Interaction Coefficients for the Colorectal Cancer Tissue

J Med Phys. 2022 Oct-Dec;47(4):381-386. doi: 10.4103/jmp.jmp_29_22. Epub 2023 Jan 10.

Authors

Emmanuel Okon Esien-Umo¹, Joseph Abebe Obu², Ndubuisi Ozoemena Chiaghanam¹, Theophilus Ipeh Ugbem³, Nneoyi Onen Egbe¹

Affiliations

¹ Department of Radiography and Radiological Sciences, Faculty of Allied Medical Sciences, University of Calabar, Calabar, Nigeria.
² Department of Physics, Faculty of Physical Sciences, University of Calabar, Calabar, Nigeria.
³ Department of Pathology, University of Calabar, Calabar, Nigeria.

Abstract

Purpose: The application of radiotherapy to the treatment of cancer requires the knowledge of photon interaction coefficients such as mass attenuation (μ_m) and mass energy-absorption coefficients (μ_en/ρ). Although these coefficients have been determined for different tissues, it is lacking for the colorectal cancer (CRC) tissue in the literature. This study determines the μ_m and μ_en/ρ for the CRC tissue within the radiotherapy energy range.

Materials and methods: The CRC tissue from autopsy patients was freeze-dried, grounded into a fine powder, and made into pellets of 1 cm thickness. The elements detected in the CRC tissue using Rutherford backscattering spectrometry were used in XCOM to determine the theoretical values of μ_m and μ_en/ρ. The CRC tissue was again exposed to X-rays of energies of 6 and 15MV, respectively, to determine its experimental values of μ_m and μ_en/ρ.

Results: Elements detected included carbon, oxygen and nitrogen making up 96.67%, high atomic number and trace elements making up the remaining 3.33% fraction of the CRC tissue.

Conclusion: The theoretical and experimental μ_m and μ_en/ρ values showed a good agreement of about 2% difference between them. These values can be used to simulate the CRC tissue with respect to μ_m and μ_en/ρ.

Keywords: Colorectal cancer tissue; elemental composition; mass attenuation coefficient; mass energy-absorption coefficient.