Sains Malaysiana 46(9)(2017): 1407–1411

http://dx.doi.org/10.17576/jsm-2017-4609-08

 

Monte Carlo Simulation of 6 MV Flattening Filter Free Photon Beam of TrueBeam STx LINAC at Songklanagarind Hospital

(Simulasi Monte Carlo 6 MV Perataan Tanpa Penurasan Alur Foton TrueBeam STx LINAC di Hospital Songklanagarind)

 

M. ARIF EFENDI^{1 2}, AMPORN FUNSIAN², THAWAT CHITTRAKARN¹ & TRIPOB BHONGSUWAN¹*

 

¹Department of Physics, Faculty of Science, Prince of Songkla University, 90110 Hatyai City, Songkla, Thailand

 

²Department of Radiology, Faculty of Medicine, Prince of Songkla University

90110 Hatyai City, Songkla, Thailand

 

Received: 31 August 2016/ Accepted: 17 January 2017

 

ABSTRACT

In this study, 6 MV photon beam of TrueBeam STx Varian LINAC with Flattening Filter Free (FFF) was simulated using PRIMO code. The depth dose profiles for various jaws open fields and cross beam profiles for various depths inside water phantom were determined using Monte Carlo (MC) simulation technique and validated with experimental result. The experiments were performed using the Source to Surface Distance (SSD) technique with a 100 cm distance from target to the surface of water. Simulation used 10⁹ histories with the same configurations with experiments. The depth dose profiles and cross beam profiles of 6 MV FFF photon beam was determined using MC simulations and compared with experimental results. The results showed that depth dose profiles and cross beam profiles by MC simulation accurately matched with experimental results. The best result of depth dose profile was obtained at 10×10 cm2 jaws open field with 98.53% passing criterion whereas cross beam profile was obtained at 10 cm depth inside water phantom with 88.96% passing criterion. The discrepancies were caused by scatter of particle and incompatibility of primary beam in PRIMO with experiment.

 

Keywords: Flattening Filter Free (FFF); Linear Accelerator (LINAC); Monte Carlo simulation; PRIMO Code

 

ABSTRAK

Dalam kajian ini, 6 MV alur foton daripada TrueBeam STx Varian LINAC dengan perataan tanpa penurasan (FFF) disimulasikan menggunakan kod PRIMO. Profil kedalaman dos untuk pelbagai ukuran rahang dan profil melintang alur untuk pelbagai kedalaman dalam fantom air telah ditentukan dengan menggunakan teknik simulasi Monte Carlo (MC) dan disahkan secara eksperimen. Uji kaji telah dijalankan dengan menggunakan teknik jarak sumber kepada permukaan (SSD) dengan jarak 100 cm dari sasaran ke permukaan air. Simulasi menggunakan 10⁹ peristiwa, konfigurasi yang sama dengan uji kaji. Profil kedalaman dos dan profil melintang alur daripada 6 MV FFF alur foton ditentukan dengan menggunakan simulasi MC dan dibandingkan dengan keputusan uji kaji. Hasil kajian menunjukkan bahawa hasil simulasi MC daripada profil kedalaman dos dan profil melintang alur adalah sepadan tepat dengan keputusan uji kaji. Keputusan terbaik profil kedalaman dos adalah pada 10×10 cm2 dengan kriteria lulus 98.53%. Keputusan terbaik profil melintang alur adalah pada kedalaman 10 cm dalam fantom air dengan kriteria lulus 88.96%. Percanggahan adalah disebabkan oleh serakan zarah dan ketidaksesuaian alur utama dalam PRIMO berbanding dengan uji kaji.

 

Kata kunci: Kod PRIMO; pemecut linear (LINAC); perataan tanpa penurasan (FFF); simulasi Monte Carlo

REFERENCES

 

Abdul Haneefa, K., Siji Cyriac, T., Musthafa, M.M., Ganapathi Raman, R., Hridya, V.T., Siddhartha, A. & Shakir, K.K. 2014. FLUKA Monte Carlo for basic dosimetric studies of dual energy medical linear accelerator. Journal of Radiotherapy 46(37): 46098370.

American Cancer Society. 2015. Cancer Facts & Figures. Atlanta, Ga: American Cancer Society.

Atarod, M., Shokrani, P. & Azarnoosh, A. 2013. Out-of-field beam characteristics of a 6 MV photon beam: Results of a Monte Carlo study. Applied Radiation and Isotopes 72: 182-194.

Belosi, M.F., Rodriguez, M., Fogliata, A., Cozzi, L., Sempau, J., Clivio, A., Nicolini, G., Vanetti, E., Krauss, H., Khamphan, C., Fenoglietto, P., Puxeu, J., Fedele, D., Mancosu, P. & Brualla, L. 2014. Monte Carlo simulation of truebeam flattening-filter-free beams using varian phase-space files: Comparison with experimental data. Medical Physics 41(5): 51707.

Beyer, G.P. 2013. Commissioning measurements for photon beam data on three truebeam linear accelerators, and comparison with trilogy and clinac 2100 linear accelerators. Journal of Applied Clinical Medical Physics 14(1): 273-288.

Chetty, I.J., Curran, B., Cygler, J.E., DeMarco, J.J., Ezzell, G., Faddegon, B.A., Kawrakow, I., Keall, P.J., Liu, H., Charlie Ma, C.M., Rogers, D.W.O., Seuntjens, J., Sheikh-Bagheri, D. & Siebers, J.V. 2007. Report of the AAPM Task Group No. 105: Issues associated with clinical implementation of Monte Carlo-based photon and electron external beam treatment planning. Medical Physics 34(12): 4818-4853.

Graves, Y.J., Jia, X. & Jiang, S.B. 2013. Effect of statistical fluctuation in Monte Carlo based photon beam dose calculation on gamma index evaluation. Physics in Medicine and Biology 58(6): 1839-1854.

Huang, Y., Alfredo Siochi, R. & Bayouth, J.E. 2012. Dosimetric properties of a beam quality-matched 6 MV unflattened photon beam. Journal of Applied Clinical Medical Physics 13(4): 71-81.

Konefał, A., Bakoniak, M., Orlef, A., Maniakowski, Z. & Szewczuk, M. 2015. Energy spectra in water for the 6 MV x-ray therapeutic beam generated by clinac-2300 linac. Radiation Measurements 72: 12-22.

Low, D.A., Harms, W.B., Mutic, S. & Purdy, J.A. 1998. A technique for the quantitative evaluation of dose distributions. Medical Physics 25(5): 656-661.

Mayles, P., Nahum, A. & Rosenwald, J-C. 2007. Handbook of Radiotherapy Physics: Theory and Practice. Boca Raton: CRC Press.

Reis Junior, J.P., Salmon, H., Menezes, A.F., Pavan, G.A., Rosa, L.A.R. & Silva, A.X. 2014. Simulation of Siemens ONCORTM expression linear accelerator using phase space in the MCNPX code. Progress in Nuclear Energy 70: 64-70.

Rodriguez, M., Sempau, J. & Brualla, L. 2013. PRIMO: A graphical environment for the Monte Carlo simulation of varian and elekta linacs. Strahlentherapie Und Onkologie 189(10): 881-886.

Rodriguez, M., Sempau, J., Fogliata, A., Cozzi, L., Sauerwein, W. & Brualla, L. 2015. A geometrical model for the Monte Carlo simulation of the truebeam linac. Physics in Medicine and Biology 60(11): N219-N229.

Saidi, P., Tenreiro, C. & Sadeghi, M. 2013. Variance Reduction of Monte Carlo Simulation in Nuclear Engineering Field. Rijeka, Croatia: INTECH Open Access Publisher.

Sardari, D., Maleki, R., Samavat, H. & Esmaeeli, A. 2010. Measurement of depth-dose of linear accelerator and simulation by use of Geant4 computer code. Reports of Practical Oncology & Radiotherapy 15(3): 64-68.

Tartar, A. 2014. Monte Carlo simulation approaches to dose distributions for 6 MV photon beams in clinical linear accelerator. Biocybernetics and Biomedical Engineering 34(2): 90-100.

Xiao, Y., Kry, S.F., Popple, R., Yorke, E., Papanikolaou, N., Stathakis, S., Xia, P., Huq, S., Bayouth, J., Galvin, J. & Yin, F.F. 2015. Flattening filter-free accelerators: A report from the AAPM therapy emerging technology assessment work group. Journal of Applied Clinical Medical Physics 16(3): 5219.

 

 

*Corresponding author; email: tripop.b@psu.ac.th