Bazı Biyolojik Bileşiklerin Kütlesel Zayıflatma Katsayılarının Monte Carlo Yöntemi ile Hesaplanması

Abstract

Bu çalışma insan vücudunda bulunan 13 biyolojik numunenin toplam kütlesel zayıflatma katsayılarını Monte Carlo yöntemi ile hesaplamayı amaçlamaktadır. Simülasyonlarda, noktasal bir foton kaynağı, tek enerjili fotonları paralel bir demet şeklinde silindirik bir soğurucuya yönlendirmiş ve soğurucunun arkasına disk şeklinde küçük bir vakum dedektör yerleştirilmiştir. Problem geometrisindeki tüm bileşenler numune dışındaki materyallerle etkileşimi önlemek için bir vakum küresi ile çevrelenmiştir. Bu şekilde, simülasyon düzeneği dedektör akısına saçılan fotonların katkı yapmamasını sağlamıştır. Simülasyonlar, 10 keV-20 MeV enerji aralığında 36 farklı foton enerjisinde gerçekleştirilmiştir. Çalışmanın sonuçları literatürde var olan ölçüm değerleri ve teorik veriler ile çok iyi uyum göstermektedir ve Monte Carlo tekniğinin kütlesel zayıflatma katsayılarının hesaplanması için bir alternatif olarak kullanılabileceğini ortaya çıkarmıştır.

Keywords

• Fotonlar,Kütlesel zayıflama katsayısı,Biyolojik materyaller,Monte Carlo simülasyonları

Monte Carlo Calculation of Mass Attenuation Coefficients of Some Biological Compounds

Abstract

This study aims to compute total mass attenuation coefficients of thirteen biological samples found in human body using the well-established Monte Carlo method. The simulations utilize a point photon source which emits mono-energetic photons directed as a parallel beam toward the cylindrical absorber behind which was placed a small disc-shaped vacuum detector. All the components in the problem geometry were surrounded by a vacuum sphere to avoid any interactions in materials other than the sample. In this manner, the simulation setup ensures that no scattered photons contribute to the flux in the detector. The simulations were carried out at thirty-six different photon energies between 10 keV-20 MeV. The results of this study indicate very good agreement with theoretical data and measurement values available in literature and indicate that Monte Carlo technique may be used as an alternative for calculations of mass attenuation coefficients.

Keywords

• Photons,Mass attenuation coefficient,Biological materials,Monte Carlo Simulations

References

1. [1] T.E. Johnson, Introduction to Health Physics. McGraw-Hill Education, 2017.
2. [2] J.K. Shultis and R.E. Faw, Fundamentals of Nuclear Science and Engineering. Marcel Dekker, 2002.
3. [3] J.H. Hubbell, “Review and history of photon cross section calculations,” Phys. Med. Biol. 51(13), R245-R262, 2006.
4. [4] M.J. Berger, J.H. Hubbell, S.M. Seltzer, J. Chang, J.S. Coursey, R. Sukumar, D.S. Zucker and K. Olsen NIST Standard Reference Database 8 (XGAM). NIST, PML, Radiation Physics Division, 2019.
5. [5] R. Jonson, “Mass attenuation coefficients, quantities and units for use in bone mineral determinations,” Osteoporosis International 3(2), 103-106, 1993.
6. [6] R.H. Millar and J.R. Greening, “Experimental X-ray mass attenuation coefficients for materials of low atomic number in the energy range 4 to 25 keV,” Journal of Physics B: Atomic and Molecular Physics, 7(17), 2001.
7. [7] M. Angelone, T. Bubba, and A. Esposito, “Measurement of the mass attenuation coefficient for elemental materials in the range 6⩽Z⩽82 using X-rays from 13 up to 50 keV,” Applied Radiation and Isotopes 55(4), 505-11, 2001.
8. [8] N. Ekinci and N. Astam, “Measurement of mass attenuation coefficients of biological materials by energy dispersive X-ray fluorescence spectrometry,” Radiation Measurements 42(3), 428-430, 2007.

9. [9] J.H. Hubbell, “Review of photon interaction cross section data in the medical and biological context,” Phys. Med. Biol. 44, R1-R22, 1999.
10. [10] A. Akar, H. Baltas, U. Cevik, F. Korkmaz, and N.T. Okumusoglu, “Measurement of attenuation coefficients for bone, muscle, fat and water at 140, 364 and 662 keV gamma-ray energies,” Journal of Quantitative Spectroscopy and Radiative Transfer 102(2), 203-211, 2006.
11. [11] S.R. Manohara and S.M. Hanagodimath, “Studies on effective atomic numbers and electron densities of essential amino acids in the energy range 1 keV-100 GeV,” Nuclear Instruments and Methods in Physics Research B 258, 321-328, 2007.
12. [12] P.P. Pawar and G. K. Bichile, “Studies on mass attenuation coefficient, effective atomic number and electron density of some amino acids in the energy range 0.122-1.330 MeV,” Radiation Physics and Chemistry 92, 22-27, 2013.
13. [13] B.M. Ladhaf and P.P. Pawar, “Studies on mass energy-absorption coefficients and effective atomic energy-absorption cross sections for carbohydrates,” Radiation Physics and Chemistry 109, 89-94, 2015.
14. [14] P.S. Kore, P.P. Pawar, and T.P. Selvam, “Evaluation of radiological data of some saturated fatty acids using gamma ray spectrometry,” Radiation Physics and Chemistry 119, 74-79, 2016.
15. [15] D.K. Gaikwad, P.P. Pawar, and T.P. Selvam, “Measurement of attenuation cross-sections of some fatty acids in the energy range 122–1330 keV,” Pramana - J. Phys. 87(1), 1-12, 2016.
16. [16] B.T. Tonguc, H. Arslan, M.S. Al-Buriahia, “Studies on mass attenuation coefficients, effective atomic numbers and electron densities for some biomolecules,” Radiation Physics and Chemistry 153, 86-91, 2018.
17. [17] B.O. Elbashir, M.G. Dong, M.I. Sayyed, S.A. M. Issa, K.A. Matori, and M.H.M. Zaid, “Comparison of Monte Carlo simulation of gamma ray attenuation coefficients of amino acids with XCOM program and experimental data,” Results in Physics 9, 6-11, 2018.
18. [18] P. Andreo, “Monte Carlo techniques in medical radiation physics,” Physics in medicine and biology, 36(7), 861-920, 1991.
19. [19] C.J. Werner (editor). MCNP Users Manual - Code Version 6.2, LA-UR-17-29981, 2017.
20. [20] S. Agostinelli et al. “Geant4 - A Simulation Toolkit,” Nucl. Instrum. Meth. A, 506, 250-303, 2003.
21. [21] P. Arce, P. Rato, M. Canadas and J.I. Lagares, “GAMOS: A GEANT4-based easy and flexible framework for nuclear medicine applications,” 2008 IEEE Nuclear Science Symposium and Medical Imaging Conference (2008 NSS/MIC), 2008.