Investigation of Reduction of the Uncertainty of Monte Carlo Dose Calculations in Oncor® Clinical Linear Accelerator Simulation Using the DBS Variance Reduction Technique in Monte Carlo Code BEAMnrc

Asadi, Amin; Nickfarjam, Abolfazl; Jabari, Keyvan

Volume 25, Issue 7 (oct 2017) JSSU 2017, 25(7): 512-525 | Back to browse issues page

Mendeley

Zotero

RefWorks

Asadi A, Nickfarjam A, Jabari K. Investigation of Reduction of the Uncertainty of Monte Carlo Dose Calculations in Oncor® Clinical Linear Accelerator Simulation Using the DBS Variance Reduction Technique in Monte Carlo Code BEAMnrc . JSSU 2017; 25 (7) :512-525
URL: http://jssu.ssu.ac.ir/article-1-4016-en.html

Investigation of Reduction of the Uncertainty of Monte Carlo Dose Calculations in Oncor® Clinical Linear Accelerator Simulation Using the DBS Variance Reduction Technique in Monte Carlo Code BEAMnrc

Amin Asadi

, Abolfazl Nickfarjam ^*

, Keyvan Jabari

Abstract: (4704 Views)

Purpose: To study the benefits of Directional Bremsstrahlung Splitting (DBS) dose variance reduction technique in BEAMnrc Monte Carlo (MC) code for Oncor® linac at 6MV and 18MV energies.

Materials and Method: A MC model of Oncor® linac was built using BEAMnrc MC Code and verified by the measured data for 6MV and 18MV energies of various field sizes. Then Oncor® machine was modeled running DBS technique, and the efficiency of total fluence and spatial fluence for electron and photon, the efficiency of dose variance reduction of MC calculations for PDD on the central beam axis and lateral dose profile across the nominal field was measured and compared.

Result: With applying DBS technique, the total fluence of electron and photon increased in turn 626.8 (6MV) and 983.4 (6MV), and 285.6 (18MV) and 737.8 (18MV), the spatial fluence of electron and photon improved in turn 308.6±1.35% (6MV) and 480.38±0.43% (6MV), and 153±0.9% (18MV) and 462.6±0.27% (18MV). Moreover, by running DBS technique, the efficiency of dose variance reduction for PDD MC dose calculations before maximum dose point and after dose maximum point enhanced 187.8±0.68% (6MV) and 184.6±0.65% (6MV), 156±0.43% (18MV) and 153±0.37% (18MV), respectively, and the efficiency of MC calculations for lateral dose profile remarkably on the central beam axis and across the treatment field raised in turn 197±0.66% (6MV) and 214.6±0.73% (6MV), 175±0.36% (18MV) and 181.4±0.45% (18MV).

Conclusion: Applying dose variance reduction technique of DBS for modeling Oncor® linac with using BEAMnrc MC Code surprisingly improved the fluence of electron and photon, and it therefore enhanced the efficiency of dose variance reduction for MC calculations. As a result, running DBS in different kinds of MC simulation Codes might be beneficent in reducing the uncertainty of MC calculations.

Keywords: BEAMnrc, DOSXYZnrc, Linear Clinical accelerator, Directional Bremsstrahlung Splitting

Full-Text [PDF 1173 kb] (1299 Downloads)

Type of Study: Original article | Subject: Medical Physics
Received: 2016/12/19 | Accepted: 2017/07/9 | Published: 2017/11/8

References

3. Kawrakow I, Rogers D. EGSnrc user manual. National Research Center of Canada Report PIRS-701 2001.

4. Kawrakow I, Rogers D. The EGSnrc code system. NRC Report PIRS-701, NRC, Ottawa 2000.

5. Rogers D, Ma C, Ding G, Walters B, Sheikh-Bagheri D, Zhang G. BEAMnrc users manual. NRC report PIRS 2001.

6. Treurniet J, Walters B, Rogers D. BEAMnrc, DOSXYZnrc and BEAMDP GUI user’s manual. NRC Report PIRS 2001; 623.

7. Kawrakow I, Rogers D, Walters B. Large efficiency improvements in BEAMnrc using directional bremsstrahlung splitting. Medical physics 2004; 31(10): 2883-98.

8. Kawrakow I. egspp: the EGSnrc C++ class library. NRCC Report PIRS-899. National Research Council of Canada 2005.

9. Kawrakow I, Mainegra-Hing E, Rogers D. EGSnrcMP: the multi-platform environment for EGSnrc. National Research Council of Canada, Ottawa 2006.

10. Walters B, Kawrakow I, Rogers D. DOSXYZnrc users manual. Nrc Report Pirs 2005;794.

11. Kawrakow I, Walters B. Efficient photon beam dose calculations using DOSXYZnrc with BEAMnrc. Medical physics 2006; 33(8): 3046-56.

12. Ma C, Rogers D. BEAMDP users manual. NRC Report PIRS-0509 (D) 1995.

13. Ma C, Rogers D. BEAMDP as a general-purpose utility. NRC Report PIRS 509e (rev A). 2004.

14. McGowan H, Faddegon B, Ma C. STATDOSE for 3D dose distributions 2007.

15. Rogers D, Walters B, Kawrakow I. BEAMnrc users manual. Nrc Report Pirs 2009; 509: 12.

16. Jabbari K, Anvar HS, Tavakoli MB, Amouheidari A. Monte carlo simulation of siemens oncor linear accelerator with beamnrc and dosxyZnrc code. J medical signals and sensors 2013; 3(3):172.

17. Romano PK, Forget B. The OpenMC monte carlo particle transport code. Annals of Nuclear Energy 2013;51:274-81.

18. Wang X, Zhu L, Zhang Y, Liu X. An investigation of the efficiency in simulating 6 MV medical accelerator using OMEGA/BEAM. Nuclear Techniques 2013; 36(2).

19. Khan FM, Gibbons JP. Khan's the physics of radiation therapy: Lippincott Williams & Wilkins; 2014.

20. Feng Z, Yue H, Zhang Y, Wu H, Cheng J, Su X. Monte Carlo simulation of beam characteristics from small fields based on TrueBeam flattening-filter-free mode. Radiation Oncology 2016; 11(1): 30.

21. Fu G, Li M, Song Y, Dai J. A dosimetric evaluation of flattening filter-free volumetric modulated arc therapy in nasopharyngeal carcinoma. J medical physics/Association of Medical Physicists of India 2014; 39(3): 150.

22. Ashokkumar S, Raj NAN, Sinha SN, Yadav G, Thiyagarajan R, Raman K, et al. Comparison of head scatter factor for 6MV and 10MV flattened (FB) and unflattened (FFF) photon beam using indigenously designed columnar mini phantom. Journal of medical physics/Association of Medical Physicists of India 2014; 39(3): 184.

23. Almberg S, Frengen J, Lindmo T. Monte Carlo study of in field and out of field dose distributions from a linear accelerator operating with and without a flattening filter. Medical physics 2012; 39(8): 5194-203.