Estimation of dosimetric parameters of I-125 brachytherapy source model 6711 using GATE8.1 code

Authors

10.22052/7.3.1

Abstract

Brachytherapy is one type of internal radiation therapy where radiation sources, which are usually encapsulated are placed as close as possible to the tumor site inside the patient's body. In this technique, it is important to determine dose distribution around the brachytherapy capsule. Hereby, in this paper, dosimetric parameters of I-125 brachytherapy source model 6711 are estimated according to TG-43U1 protocol using GATE 8.1 Monte Carlo code.
In this work, we used GATE_v8.1 to calculate dosimetric parameters of the I-125 brachytherapy source model 6711. At first, validation of the GATE platform were performed by some criteria such as radial dose function, 2D anisotropy function inside liquid water according to the AAPM TG-43U1. On the other hand, since the attenuation coefficient of the sources in the water phantom is different from that of various tissues, the effects of the various tissues on the radial dose function parameter of the I-125 brachytherapy source were investigated using GATE 8.1 code.
Dosimetric parameters of simulated I-125 brachytherapy capsule show good consistency compared with the other study. The maximum average deviation was about 3.61% and 7.29% at radial dose function and anisotropy function, respectively. The relative deviation of radial dose function in the fat, muscle, breast and lung tissue compared with water phantom in  radial distance of 5cm were about 68.73%, 10.98%, 25.83% and 12.23%, respectively.
There was a good agreement between the results of this work and other study in calculation of dosimetric parameters of brachytherapy I-125 source base on the recommendations of TG-43U1 protocol. The results show that the dosimetric parameters of I-125 brachytherapy can be calculated using the GATE code and appropriate physic list in spite of low energy of radiation and high variation in dose rate with increasing distance from the center of the source. The results of the dose calculation in different phantom could be used in clinical treatment planning systems.

 

Keywords


[1] A.V. Rodriguez, P.Q. Alcona, M.L. Rodriguez, F. Gutt and E. Almeida. Dosimetric parameters estimation using PENELOPE Monte Carlo simulation code: Model 6711 a 125I brachytherapy. Appl Radiat Isot. 63(1) (2005) 41–48. [2] R. Rajabi and P. Taherparvar. Monte Carlo dosimetry for a new 32P brachytherapy source using FLUKA code. J Contemp Brachytherapy. 11(1) (2019) 76–90. [3] Z. Fardi and P. Taherparvar. A Monte Carlo investigation of the dose distribution for new I-125 Low Dose Rate brachytherapy source in water and in different media. Polish Journal of Medical Physics and Engineering. 25(1) (2018) 15–22. [4] M.J. Rivard, B.M. Coursey, L.A. DeWerd, W.F. Hanson, M.S. Huq, G.S. Ibbott, M.G. Mitch, R. Nath and J.F. Williamson. Update of AAPM Task Group No.43 Report: A revised AAPM protocol for brachytherapy dose calculations. Med Phys. 31(3) (2004) 633–674. [5] A.A. Molavi, A. Binesh and H. Moslehitabar. Dose distribution and dosimetry parameters calculation of MED3633 palladium-103 source in water phantom using MCNP. Iran J Radiat Res. 4(1) (2006) 15–19. [6] K. Weaver. Anisotropy functions for I-125 and Pd-103 sources. Med Phys. 25(12) (1998) 2271–2278. [7] P. Taherparvar and A. Sadremomtaz. Development of GATE Monte Carlo simulation for a CsI pixelated gamma camera dedicated to high resolution animal SPECT. Australas Phys Eng Sci Med. 41(1) (2018) 31–38. [8] P. Papadimitroulas. Using GATE for radiation therapy applications. Physica Medica. 32(3) (2016) 190–191. [9] H. Badry, L. Oufni, H. Ouabi and H. Hirayama. A Monte Carlo investigation of the dose distribution for 60Co High Dose Rate brachytherapy source in water and in different media. Applied Radiation and Isotopes. 136 (2018) 104–110. [10] M. Ghorbani, F. Salahshour, A. Haghparast, T. Ahmadi Moghaddas and C. Knaup. Effect of tissue composition on dose distribution in brachytherapy with various photon emitting sources. Contemp Brachytherapy. 6(1) (2014) 54–67. [11] ICRU Report No. 44, Tissue substitutes in radiation dosimetry and measurement. ICRU, Bethesda )1989(. [12] M.J. Rivard. Monte Carlo radiation dose simulations and dosimetric comparison of the model 6711 and 9011 125I brachytherapy sources. Med Phys. 36(2) (2009) 486–491.