Medical Radiology and Radiation Safety. 2020. Vol. 65. No. 1. P. 54–58

T. Medjadj¹, A.I. Ksenofontov¹, A.V. Dalechina²

An Effective Method of Simulation for the Leksell Gamma Knife Perfexion by Rotating Particles in the Phase Space File

1. National Research Nuclear University (Moscow Engineering Physics Institute) MEPhI, Moscow, Russia;
2. OJSC Neurosurgery Business Center, Moscow GammaKnife Center, Moscow, Russia
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Реферат

Purpose: To develop an effective method of Monte Carlo simulation of the GammaKnife Perfexion system by rotating particles in the phase space file (PSF). This method does not require simulating of all 192 sources that are distributed in the conical form of the Perfexion collimator. The simulation was performed only for 5 out of 192 sources for each collimator size.

Material and methods: Monte Carlo simulation of dose distribution for previous models of GammaKnife system requires phase space file for only one source, since this phase space is identical for all the 201 sources. The Perfexion model is more complex due to the non-coaxial positions of the sources and the complexity of the collimator system itself.
In this work, we present an effective method to simulate the Perfexion model using a phase space file. Penelope Monte Carlo code was used to perform this simulation. In this method, the PSF was obtained for one source in each ring, resulting in five files for each collimator size. PSF for other sources were created by azimuthal redistribution of particles, in the obtained PSF, by rotation around the Z-axis. The phase space files of the same ring were then stored together in a single file.

Results: The paper presented MC simulation using the azimuthal redistribution of particles in the phase space file by rotation around the Z-axis. The simulation has been validated comparing the dose profiles and output factors with the data of the algorithm TMR10 planning system Leksell Gamma Plan (LGP) in a homogeneous environment. The acceptance criterion between TMR10 and Monte Carlo calculations for the profiles was based on the gamma index (GI). Index values more than one were not detected in all cases, which indicates a good agreement of results. The differences between the output factors obtained in this work and the TMR10 data for collimators 8 mm and 4 mm are 0.74 and 0.73 %, respectively.

Conclusion: In this work successfully implemented an effective method of simulating the Leksell Gamma knife Perfexion system. The presented method does not require modeling for all 192 sources distributed in the conical form of the Perfexion collimator. The simulation was performed for only five sources for each collimator and their files PSF were obtained. These files were used to create the PSF files for other sources by azimuthal redistribution of particles, in these files, by rotation around the Z-axis providing correct calculations of dose distributions in a homogeneous medium for 16, 8 and 4 mm collimators.

Ключевые слова: Gamma-Knife Perfexion, Monte Carlo simulation, file phase field

Для цитирования: Medjadj T, Ksenofontov AI, Dalechina AV. An Effective Method of Simulation for the Leksell Gamma Knife Perfexion by Rotating Particles in the Phase Space File. Medical Radiology and Radiation Safety. 2020;65(1):54-8. (In Russ.).

DOI: 10.12737/1024-6177-2020-65-1-54-58

Список литературы / References

1. Maitz A, Flickinger J, Lunsford L. Gamma Knife Technology and Physics: Past, Present, and Future. Lunsford LD, Kondziolka D, Flickinger JC (eds): Gamma Knife Brain Surgery. Prog Neurol Surg. Basel, Karger. 1998;14:5-20.
2. Голанова АВ, Костюченко ВВ. Нейрорадиохирургия на Гамма-Ноже. В сб.: История стереотаксиса и радиохирургии. ред. Костюченко ВВ. – Москва, 2018;121-31. [Golanov AV, Kostjuchenko BB. Neuroradiosurgery with Gamma Knife. In: History of Stereoraxy and Radiosurgery. Kostjuchenko BB, ed. Moscow. 2018:121-31. (In Russ.)].
3. Yuan J, Lo SS, Zheng Y, Sohn JW, Sloan AE, Ellis R, et al. Development of A Monte Carlo Model for Treatment Planning Dose Verification of the Leksell Gamma Knife Perfexion Radiosurgery System. J Applied Clinical Medical Physics. 2016;17(4):190–201.
4. Lindquist C, Paddick I. The Leksell Gamma Knife Perfexion and Comparisons with Its Predecessors. Neurosurgery. 2007;61:130-40.
5. Ma L, Kjäll P, Novotny J, Nordström H, Johansson J, Verhey L. A Simple and Effective Method for Validation and Measurement of Collimator Output Factors for Leksell Gamma Knife Perfexion. Phys Med Biol. 2009;54:3897-907.
6. Salvat F, Jose M, Josep S. PENELOPE-2008: A Code System for Monte Carlo Simulation of Electron and Photon Transport, OECD-NEA, Report 6416, Issy-les-Moulineaux, France. 2009.
7. Bush K, Zavgorodni SF, Beckham WA. Azimuthal Particle Redistribution for the Reduction of Latent Phase-Space Variance in Monte Carlo Simulations. Phys Med. Biol. 2007;52:4345-60.
8. Brualla L, Sauerwein W. On the Efficiency of Azimuthal and Rotational Splitting for Monte Carlo Simulation of Clinical Linear Accelerators. Radiation Phys and Chemistry. 2010;79:929-32.
9. Cho YB,  van Prooijen M, Jaffray DA, Islam MK. Verification of Source and Collimator Configuration for Gamma Knife Perfexion Using Panoramic Imaging. Med Phys. 2010;37(3):1325-31.
10. Low DA, Harms WB, Mutic S, Purdy JA. A Technique for the Quantitative Evaluation of Dose Distributions. Med Phys. 1998;25:656-61.

PDF (RUS) Полная версия статьи

Conflict of interest. The authors declare no conflict of interest.

Financing. The study had no sponsorship.

Contribution. Article was prepared with equal participation of the authors.

Article received: 08.04.2019. Accepted for publication: 11.12.2019.