Department of Radiation Oncology,National Cancer Center/Cancer Hospital,Chinese Academy of Medical Science,Peking Union Medical Collage,Beijing 100021,China
Abstract Objective To obtain the high-resolution dose distribution for the single source channel of Leksell 4C gamma knife. Methods A parallel computing platform based on the Message Passing Interface (MPI) and Monte Carlo Code MCNPX was established. The ring-shaped detector and two pre-validated variance reduction techniques (emission direction-biased sampling of source and termination of electron tracking in partial structures) were adopted to derive the high-resolution dose distribution for the single source channel of Leksell 4C gamma knife. The effect of cut-off energy for both photon and electron on the accuracy of simulation outcomes was evaluated and statistically compared. Results Compared with previous findings,the spatial resolution of the dose distribution for the single source channel obtained in this study was higher (radial resolution=0.1 mm) with less statistical error (<1%).The calculation time was acceptable (approximately 24 h).For the 4-,8-,14-and 18-mm variable collimators,the penumbra and full width at the half maximum (FWHM) for single side were 1.0,1.1,1.2,1.3 mm and 2.2,4.3,7.3,9.3 mm,respectively,which were consistent with previous studies. The difference of the simulation results was extremely small between different cut-off energy for photon (1 keV vs.10 keV).However,the simulation results significantly differ between 1 and 521 keV electronic cut-off energy. Conclusions The MCNPX parallel computing platform based on the MPI environment can be utilized to derive highly accurate dose distribution with high resolution in acceptable calculation time. The cut-off energy of the photon and electron should be cautiously set up during simulation.
Corresponding Authors:
Dai Jianrong,Email:jianrong_dai@yahoo.com
Cite this article:
Tian Yuan,Xu Yingjie,Song Yixin et al. Monte Carlo simulation of accurate dose distribution with high resolution for the single source channel of Leksell 4C gamma knife[J]. Chinese Journal of Radiation Oncology, 2018, 27(8): 780-783.
Tian Yuan,Xu Yingjie,Song Yixin et al. Monte Carlo simulation of accurate dose distribution with high resolution for the single source channel of Leksell 4C gamma knife[J]. Chinese Journal of Radiation Oncology, 2018, 27(8): 780-783.
[1] Cheung JY,Yu KN,Ho RT,et al. Monte Carlo calculated output factors of a Leksell Gamma Knife unit[J].Phys Med Biol,1999,44(12):N247-249.DOI:10.1088/0031-9155/44/12/401. [2] Cheung JY,Yu KN,Ho RT,et al. Monte Carlo calculations and GafChromic film measurements for plugged collimator helmets of Leksell Gamma Knife unit[J].Med Phys,1999,26(7):1252-1256.DOI:http://dx.doi.org/10.1118/1.598639. [3] Cheung YC,Yu KN,Ho RT,et al. Stereotactic dose planning system used in Leksell Gamma Knife model-B:EGS4 Monte Carlo versus GafChromic films MD-55[J].Appl Radiat Isot,2000,53(3):427-430.DOI:10.1016/S0969-8043(99)00285-7. [4] Cheung JY,Yu KN,Yu CP,et al. Dose distributions at extreme irradiation depths of gamma knife radiosurgery:EGS4 Monte Carlo calculations[J].Appl Radiat Isot,2001,54(3):461-465.DOI:10.1016/S0969-8043(00)00283-9. [5] Cheung JY,Yu KN,Yu CP,et al. Choice of phantom materials for dosimetry of Leksell Gamma Knife unit:a Monte Carlo study[J].Med Phys,2002,29(10):2260-2261.2.DOI:10.1118/1.1508797. [6] Cheung JY,Yu KN,Chan JF,et al. Dose distribution close to metal implants in gamma knife radiosurgery:a Monte Carlo study[J].Med Phys,2003,30(3):1812-1815.DOI:10.1118/1.1582811. [7] Cheung JY,Yu KN.Dose distribution close to metal implants in gamma knife radiosurgery:a Monte Carlo study[J].Med Phys,2005,32(5):1448-1449.DOI:10.1118/1.1901183. [8] Cheung JY,Yu KN.Study of scattered photons from the collimator system of Leksell gamma knife using the EGS4 Monte Carlo code[J].Med Phys,2006,33(1):41-45.DOI:10.1118/1.2143138. [9] Cheung JY,Ng KP,Yu CP,et al. Comparative study of treatment dose plans after the refinement of Leksell Gamma Knife single-beam dose profiles[J].Med Phys,2007,34(9):3556-3561.DOI:10.1118/1.2766760. [10] Cheung JY,Yu KN,Yu CP,et al. Monte Carlo calculation of single-beam dose profiles used in a gamma knife treatment planning system[J].Med Phys,1998,25(9):1673-1675.DOI:http://dx.doi.org/10.1118/1.598347. [11] Al-Dweri FM,Lallena AM,Vilches M.A simplified model of the source channel of the Leksell GammaKnife tested with PENELOPE[J].Phys Med Biol,2004,49(12):2687-2703.DOI:http://dx.doi.org/10.1088/0031-9155/49/12/015. [12] Al-Dweri FM,Lallena AM.A simplified model of the source channel of the Leksell gamma knife:testing multisource configurations with PENELOPE[J].Phys Med Biol,2004,49(15):3441-3453.DOI:http://dx.doi.org/10.1088/0031-9155/49/15/009. [13] Al-Dweri FM,Rojas EL,Lallena AM.Effects of bone-and air-tissue inhomogeneities on the dose distributions of the leksell gamma knife calculated with PENELOPE[J].Phys Med Biol,2005,50(23):5665-5678.DOI:http://dx.doi.org/10.1088/0031-9155/50/23/018. [14] Trnka J,Novotny J Jr,Kluson J.MCNP-based computational model for the Leksell gamma knife[J].Med Phys,2007,34(1):63-75.DOI:10.1118/1.2401054. [15] 王磊,王侃,余纲林.基于MPI的MCNP程序的并行计算研究[J].核电子学与探测技术,2008,28(1):163-165. Wang L,Wang K,Yu GL.Parallel Computing of MCNP Program based on MPI[J].Nucl Elect Detect Technol,2008,28(1):163-165. [16] 田源,徐英杰,任信信,等.降方差技术对伽玛刀单源剂量场模特卡罗模拟计算效率和模拟结果准确性的影响[J].中华放射肿瘤学杂志,2016,25(8):855-860.DOI:10.3760/cma.j.issn.1004-4221.2016.08.014. Tian Y,Xu YJ,Ren ZZ,et al. The effect of reduced variance technique on the efficiency and accuracy of model Carlo simulation of single source dose field of gamma knife[J].Chin J Radiat Oncol,2016,25(8):855-860.DOI:10.3760/cma.j.issn.1004-4221.2016.08.014. [17] Tian Y,Wang H,Xu Y,et al. Comparison of dosimetric characteristics between stationary and rotational gamma ray stereotactic radiosurgery systems based on Monte Carlo simulation[J].Biomed Phys Engineer Exp,2016,2(4):045014.DOI:10.1088/2057-1976/2/4/045014. [18] Wu A,Lindner G,Maitz AH,et al. Physics of gamma knife approach on convergent beams in stereotactic radiosurgery[J].Int J Radiat Oncol Biol Phys,1990,18(4):941-949.DOI:10.1016/0360-3016(90)90421-F.