New variance reduction techniques for MCNP6 for external radiation therapy calculations. (September 2016)

• Record Type: Journal Article
• Authors: Papp, Ildikó; Stelczer, Gábor; Pesznyák, Csilla; Szieberth, Máté; Czifrus, Szabolcs
• Is Part Of: Physica medica. Volume 32(2016)Supplement 3
• Page Start: 203
• Publication Date: 2016-09
• Subjects: Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2016.07.689
• Languages: English
• ISSNs: 1120-1797

Abstract

Abstract : Introduction: Over the last years, Monte Carlo methods have taken an important role in radiation therapy. One of the main disadvantages of these methods is their huge computational demand. Purpose: The goal of the current work is to describe and develop new variance reduction methods relevant to external radiation therapy in the MCNP6 source code. Materials and methods: In this study a new filter-technique and filtered azimuthal particle redistribution (fAPR) method were developed. To test the efficiency of these methods a modified FOM value was introduced. Results: The modified FOM value of the fAPR technique has been found to be approximately 5 times higher in the case of percentage depth dose curves than the modified FOM value of the filter technique. At the same time when simulating dose profiles this ratio has been found to be 5.5 in advance for the fAPR technique as well. Calculated data was compared to measured values and good agreement was found in the case of the filtered and fAPR results. Conclusion: Computational time can be significantly reduced by using the new methods which have been tested to give unbiased results. Results show that the filtered technique combined with azimuthal particle redistribution is a beneficial method in radiation therapy.