SOBRE LA POSIBILIDAD DE USAR EL MÉTODO DE REGULARIZACIÓN DE TIKHONOV PARA RECONSTRUIR EL ESPECTRO DE ENERGÍA DE UN HAZ CLÍNICO DE ELECTRONES
ON THE POSSIBILITY OF USE THE TIKHONOV REGULARIZATION METHOD TO RECONSTRUCT THE ENERGY SPECTRUM OF A CLINICAL ELECTRON BEAM
DOI:
https://doi.org/10.15446/mo.n60.75527Keywords:
Fotones Contaminantes, Fredholm, Índice Gamma, PENELOPE (es)Contamination Photons, Fredholm, Gamma Index, PENELOPE. (en)
Downloads
En radioterapia, el espectro de energía de electrones es la característica más importante para modelar la fuente de radiación cuando el propósito sea el cálculo exacto de la dosis. Usualmente, tres métodos son explorados la obtención del espectro: (i) simulación de la fuente vía Monte Carlo; (ii) medición directa vía un espectrómetro magnético y (iii) reconstrucción inversa. De entre ellos, reconstrucción inversa, a pesar de no ser el más exacto, es considerado el más apropiado por su simplicidad y rapidez. Reconstrucción inversa tiene por objeto extraer el espectro de energía a partir de la distribución de dosis en profundidad.
Ya que reconstrucción inversa es un problema mal definido, el método de regularización de Tikhonov es usado para superar la mala definición del problema y con ello obtener el espectro. La idoneidad de la reconstrucción es evaluada usando el índice gamma. Los resultados muestran que la regularización de Tikhonov es capaz de reconstruir el espectro de energía de un haz de electrones dentro del criterio clínico de aceptación del índice gamma > 95 % para 1 %/1 mm.
In radiotherapy, the electron energy spectrum is the most important characteristic for modelling the radiation source whose purpose is an accurate dose calculation.There are mainly three approaches to obtain the energy spectrum: (i) simulation of the source via Monte Carlo; (ii) direct measurement via a magnetic spectrometer and (iii) inverse reconstruction using an appropriate mathematical model. Among them, inverse reconstruction is considered the most appropriate for its simplicity and speed despite not being the most accurate. Since inverse reconstruction is an ill-posed problem the Tikhonov regularization is used to overcome this problem and thereby obtain the spectrum. The reconstruction success is evaluated using the gamma index. Results show Tikhonov regularization is able of reconstructing the energy spectrum of a clinical electron beam for the gamma index clinical acceptance of> 95 % within 1 %/1 mm.
References
J. O. Deasy, P. R. Almond, and M. T. McEllistrem, Med. Phys. 23, 675 (1996).
A. V. Chvetsov and G. A. Sandison, Med. Phys. 30, 2155 (2003).
G. Ding and D. Rogers, National Research Council of Canada Report (1995).
J. M. de la Vega, D. Guirado, M. Vilches, J. I. Perdices, and A. M. Lallena, Radiother Oncol 86, 109 (2008).
T. C. Zhu, I. J. Das, and B. E. Bjarngard, Med. Phys. 28, 1352 (2001).
L. Zhengming and D. Jette, Phys Med Biol. 44, N177 (1999).
E. B. Podgorsak et al., Vienna: International Atomic Energy Agency , 123 (2005).
B. A. Faddegon and I. Blevis, Med. Phys. 27, 514 (2000).
A. V. Chvetsov and G. A. Sandison, Med. Phys. 29, 578 (2002).
J. Deng, S. B. Jiang, T. Pawlicki, J. Li, and C.-M. Ma, Phys Med Biol. 46, 1429 (2001).
P. Bjork, T. Knoos, and P. Nilsson, Phys Med Biol. 47, 4019 (2002).
J. Deasy, P. Almond, and M. McEllistrem, Med. Phys. 21, 1369 (1994).
F. Renner, A. Schwab, R.-P. Kapsch, C. Makowski, and D. Jannek, J. Instrum. 9, P03004 (2014).
L. Gui, L. Hui, W. Ai-Dong, S. Gang, and W. Yi-Can, Chinese Phys. Lett. 25, 2710 (2008).
D. A. Low, W. B. Harms, S. Mutic, and J. A. Purdy, Med. Phys. 25, 656 (1998).
F. Salvat, J. M. Fern_andez-Varea, and J. Sempau, in Workshop proceedings, Vol. 4 (2008).
A. Brahme and H. Svensson, Acta radiologica: oncology, radiation, physics, biology 18, 244 (1979).
S. I. Kabanikhin, J INVERSE ILL-POSE P 16, 317 (2008).
P. C. Hansen, Inverse Probl. 8, 849 (1992).
A.-M. Wazwaz, Comput. Math. with Appl. 61, 2981 (2011).
Y. Xu, Y. Pei, and F. Dong, Flow Measurement and Instrumentation 50, 1 (2016).
J. Wei, G. A. Sandison, and A. V. Chvetsov, Med. Phys. 33, 354 (2006).
P. C. Hansen, Numerical algorithms 46, 189 (2007).
B. J. Gerbi, J. A. Antolak, F. C. Deibel, D. S. Followill, M. G. Herman, P. D. Higgins, M. S. Huq, D. N. Mihailidis, E. D. Yorke, K. R. Hogstrom, et al., Med. Phys. 36, 3239 (2009).
How to Cite
APA
ACM
ACS
ABNT
Chicago
Harvard
IEEE
MLA
Turabian
Vancouver
Download Citation
License
Copyright (c) 2020 MOMENTO

This work is licensed under a Creative Commons Attribution-NoDerivatives 4.0 International License.
Those authors who have publications with this journal, accept the following terms:
a. The authors will retain their copyright and will guarantee the publication of the first publication of their work, which will be subject to the Attribution-SinDerivar 4.0 International Creative Commons Attribution License that permits redistribution, commercial or non-commercial, As long as the Work circulates intact and unchanged, where it indicates its author and its first publication in this magazine.
b. Authors are encouraged to disseminate their work through the Internet (eg in institutional telematic files or on their website) before and during the sending process, which can produce interesting exchanges and increase appointments of the published work.







