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Experimental validatıon of peripheral dose distribution of electron beams for eclipse electron Monte Carlo algorithm

Published online by Cambridge University Press:  23 July 2018

Hilal Acar ,
Mustafa Caglar  and
Ayse Y. Altinok
Hilal Acar*
Affiliation:
Department of Radiation Oncology, Istanbul Medipol University, Istanbul, Turkey
Mustafa Caglar
Affiliation:
Department of Radiation Oncology, Istanbul Medipol University, Istanbul, Turkey
Ayse Y. Altinok
Affiliation:
Department of Radiation Oncology, Istanbul Medipol University, Istanbul, Turkey
*
Correspondence to: Assoc Prof. Hilal Acar, Department of Radiation Oncology, Medicine Faculty, Istanbul Medipol University, 34214, Istanbul, Turkey. Tel: +90 (535) 9395365. Fax: 90 (212) 460 70 70. E-mail: [email protected]
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Abstract

Aim

The accuracy of two calculation algorithms of the Varian Eclipse treatment planning system (TPS), the electron Monte Carlo algorithm (eMC) and general Gaussian pencil beam algorithm (GGPB) for calculating peripheral dose distribution of electron beams was investigated.

Methods

Peripheral dose measurements were carried out for 6, 9, 12, 15, 18 and 22 MeV electron beams using parallel plate ionisation chamber and EBT3 film in the slab phantom. Measurements were performed for 6×6, 10×10 and 25×25 cm2 cone sizes at dmax of each energy up to 20 cm beyond the field edges. The measured and TPS calculated data were compared.

Results

The TPS underestimated the out-of-field doses. The difference between measured and calculated doses increase with the cone size. For ionisation chamber measurement, the largest deviation between calculated and measured doses is <4·29% using the eMC, but can increase up to 8·72% of the distribution using GGPB. For film measurement, the minimum gamma analysis passing rates between measured and calculated dose distributions for all field sizes and energies used in this study were 91·2 and 74·7% for eMC and GGPB, respectively.

Findings

The use of GGPB for planning large field treatments with 6 MeV could lead to inaccuracies of clinical significance.

Keywords

electron beamseMCGGPB.EBT3 filmperipheral dose distribution
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 17 , Issue 3 , September 2018 , pp. 279 - 288
Copyright
© Cambridge University Press 2018 

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References

1. Podgorsak, E B. Review of Radiation Oncology Physics: A Handbook for Teachers and Students. International Atomic Energy Agency Vienna, Austria 2003.Google Scholar
2 Hogstrom, K R, Starkschall, G, Shiu, A S. Dose calculation algorithms for electron beams. In Purdy J A (ed.). Advances in Radiation Oncology Physics: Dosimetry, Treatment Planning and Brachytherapy. American Institute of Physics Monograph 19. New York, USA: American Institute of Physics, 1992: 900.Google Scholar
3. Strydom, W, Parker, W, Olıvares, M. Electron beams: physical and clinical aspects’ Review of Radiation Oncology Physics: A Handbook for Teachers and Students Vienna. Austria: International Atomic Energy Agency 225–248.Google Scholar
4. Janssen, J J, Korevaar, E W, van Battum, L J, Storchi, P R, Huizenga, H. A model to determine the initial phase space of a clinical electron beam from measured beam data. Phys Med Biol 2001; 46 (2): 269–286.Google Scholar
5. Fix, M K, Frei, D, Volken, W, Neuenschwander, H, Born, E J, Manser, P. Low Energy Electron Beam Dose Calculation Using eMC. Bern, Switzerland: Swiss Society of Radiobiology and Medical Physics, 2009.Google Scholar
6. Sipilä, P, Ojala, J, Kaijaluoto, S, Jokelainen, I, Kosunen, A. Gafchromic EBT3 film dosimetry in electron beams energy dependence and improved film read-out. J Appl Clin Med Phys 2016; 17 (1): 360–373.Google Scholar
7. Low, D A, Dempsey, J F. Evaluation of the gamma dose distribution comparison method. Med Phys 2003; 30: 2455–2464.Google Scholar
8. Ezzell, G A, Burmeister, J W, Dogan, N et al. IMRT commissioning: multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. Med Phys 2009; 36: 5359–5373.Google Scholar
9. Popple, R A, Weinber, R, Antolak, J A et al. Comprehensive evaluation of a commercial macro Monte Carlo electron dose calculation implementation using a standard verification data set. Med Phys 2006; 33 (6): 1540–1551.Google Scholar
10. León, M E Y, Herrera, G J A, Camacho, L M A, Villarreal, B J E, García-Garduño, O A. Evaluation of the uncertainty in an EBT3 film dosimetry system utilizing net optical density. J Appl Clin Med Phys 2016; 17 (5): 466–481.Google Scholar
11. Chow, J C, Grigorov, G N. Peripheral dose outside applicators in electron beams. Phys Med Biol 2006; 51 (12): N231–N240.Google Scholar
12. Yeboah, C, Karotki, A, Hunt, D, Holly, R. Quantification and reduction of peripheral dose from leakage radiation on Siemens Primus accelerators in electron therapy mode. J Appl Clin Med Phys 2010; 11 (3): 154–172.Google Scholar
13. Shimozato, T, Okudaira, K, Fuse, H, Tabushi, K. Monte Carlo simulation and measurement of radiation leakage from applicators used in external electron radiotherapy. Phys Med 2013; 29 (4): 388–396.Google Scholar
14. Zhu, T C, Das, I J, Bjärngard, B E. Characteristics of bremsstrahlung in electron beams. Med Phys 2001; 28 (7): 1352–1358.Google Scholar
15. Iktueren, B, Bilge, H, Karacam, S, Atkovar, G. The peripheral dose outside the applicator in electron beams of Oncor linear accelerator. Radiat Prot Dosimetry 2012; 150 (2): 192–197.Google Scholar
16. Howell, R M, Scarboro, S B, Kry, S F, Yaldo, D Z. Accuracy of out-of-field dose calculations by a commercial treatment planning system. Phys Med Biol 2010; 55 (23): 6999–7008.Google Scholar
17. Alabdoaburas, M M, Mege, J-P, Chavaudra, J et al. Experimental assessment of out-of-field dose components in high energy electron beams used in external beam radiotherapy. J Appl Clin Med Phys 2015; 16 (6): 435–448.Google Scholar
18. Xu, Z, Walsh, S E, Telivala, T P, Meek, A G., Yang, G. Evaluation of the eclipse electron Monte Carlo dose calculation for small fields. J Appl Clin Med Phys 2009; 10(3): 2834–2843.Google Scholar
19. Zhang, A, Wen, N, Nurushev, T, Burmeister, J, Chetty, I J. Comprehensive evaluation and clinical implementation of commercially available Monte Carlo dose calculation. J Appl Clin Med Phys 2013; 14 (2): 127–145.Google Scholar