Calculations of backpatch factors and conversion coefficients for the personal dose equivalent for X-ray beams used in radiodiagnostic
DOI:
https://doi.org/10.34119/bjhrv7n2-241Keywords:
backpatch factors, conversion coefficients, personal dose equivalent, x-ray beams, radiodiagnosticAbstract
The purpose of this study is to use the Monte Carlo N-Particle radiation transport code (MCNP) to calculate the conversion coefficients of air kerma for personal dose equivalent (Hp [Sv]) and Back Scattering Factors (BSF) for X-ray beams used in diagnostic radiography at potentials of 40, 50, 60, 70, 80, 90, 100, 120, and 150 kVp. Additionally, effective dose is determined using male and female anthropomorphic voxel-based simulators (REX and REGINA) as recommended by the International Commission on Radiological Protection (ICRP) Publication 110, along with tissue weight factors from ICRP Publication 103 to simulate whole-body irradiation. The results indicate that the relationship between operational metrics such as Hp and risk limitation metrics like effective dose varies from 0.14 to 0.71 for Radiation Qualities in Radiation (RQR) beams from the X-ray source assembly and up to 0.64 for Radiation Qualities based on a phantom with an added aluminium filter (RQA). When comparing the obtained values for air kerma conversion coefficients for personal dose equivalent with the value adopted by the National Commission for Nuclear Energy (CNEN) of 1.14 Sv/Gy for individual dose determination, it is observed that at low energies, the values are overestimated by up to 44%, while at high energies, the values are underestimated by up to 67%.
References
Faroux, L., Blanpain, T., Nazeyrollas, P., Tassan-Mangina, S., Herce, B., Tourneux, C., & Metz, D. (2018). Minimizing exposure to radiation in interventional cardiology using modern dose-reduction technology: Evaluation of the real-life effects. Archives of Cardiovascular Diseases Supplements, 10(1), 21.
McWilliam, A., Kennedy, J., Hodgson, C., Osorio, E. V., Faivre-Finn, C., & van Herk, M. (2017). Radiation dose to heart base linked with poorer survival in lung cancer patients. European Journal of Cancer, 85, 106-113.
Morishima, Y., Chida, K., & Watanabe, H. (2016). Estimation of the dose of radiation received by patient and physician during a videofluoroscopic swallowing study. Dysphagia, 31(4), 574-578.
ICRP 74, Conversion Coefficients for use in Radiological Protection Against External Radiation, International Commission on Radiological Protection, Pergamon Press, Oxford, 1996.
Bandalo, V., Greiter, M. B., Brönner, J., & Hoedlmoser, H. (2019). ISO 4037: 2019 validation of radiation qualities by means of half-value layer and Hp (10) dosimetry. Radiation Protection Dosimetry, 187(4), 438-450.
Principi, S., Ginjaume, M., Duch, M. A., Sánchez, R. M., Fernández, J. M., & Vano, E. (2015). Influence of dosemeter position for the assessment of eye lens dose during interventional cardiology. Radiation protection dosimetry, 164(1-2), 79-83.
Baptista, M., Di Maria, S., Barros, S., Figueira, C., Sarmento, M., Orvalho, L., & Vaz, P. (2015). Dosimetric characterization and organ dose assessment in digital breast tomosynthesis: measurements and Monte Carlo simulations using voxel phantoms. Medical physics, 42(7), 3788-3800.
IEC 61267: Medical Diagnostic x-ray Equipment – Radiation Conditions for use in the determination of characteristics. Geneva, Switzerland, 2005.
UNSCEAR, (2008). In: Sources and effects of ionizing radiation, Report of the General Assembly with Scientific Annexes, Vol. 1, New York
BRASIL. Ministério da Ciência e Tecnologia. Comissão Nacional de Energia Nuclear. Resolução CNEN 164/14. Norma CNEN NN-3.01- Diretrizes Básicas de Proteção Radiológica. Diário Oficial da União da República Federativa do Brasil, Brasília, 11 de março de 2014.
ICRP 110, Adult Reference Computational Phantoms, International Commission on Radiological Protection, Pergamon Press, Oxford, 2009.
Zankl, M., Becker, J., Fill, U., Petoussi-Henss, N., & Eckerman, K. F. (2005). GSF male and female adult voxel models representing ICRP Reference Man–the present status. The Monte Carlo Method: Versatility Unbounded in a Dynamic Computing World, 1721(1).
Zankl, M., & Wittmann, A. (2001). The adult male voxel model” Golem” segmented from whole-body CT patient data. Radiation and Environmental Biophysics, 40(2), 153-162.
ICRP 103, Recommendations of the ICRP, International Commission on Radiological Protection, Pergamon Press, Oxford, 2008.
Rosado, P. H. G., Nogueira, M. D. S., Genezini, F., & Vilela, E. C. (2008). Measurement of conversion coefficients between free in air kerma and personal dose equivalent for diagnostic X-ray beams. Radiation measurements, 43(2-6), 968-971.
Pelowitz, D. B. (2005). MCNPX user’s manual version 2.5. 0. Los Alamos National Laboratory, 76, 473.
Will, W. (1991). Measurement of conversion coefficients for calibrating individual dosemeters with respect to the operational dose quantities on the PMMA slab phantom. Radiation protection dosimetry, 37(2), 79-84.
ICRU 47, Measurement of Equivalents from External Photon and Electron Radiation. International Commission on Radiological Units e Measurements, Bethesda, USA, MD, 1992.
Will, W. (1989). Radiation protection Dosimetry. Measurement of Conversion Coefficients for Estimating Photon Individual Dose Equivalent For Cuboid Water Phantom, v.27, p.9-14.
Trojek, T., & Čechák, T. (2007). Use of MCNP code in energy dispersive X-ray fluorescence. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 263(1), 72-75.
