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Monte Carlo study on effective source to surface distance for electron beams from a mobile dedicated IORT accelerator

Published online by Cambridge University Press:  04 November 2016

Mir Rashid Hosseini Aghdam
Affiliation:
Young Researchers Club, Abhar Branch, Islamic Azad University, Abhar, Iran Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran
Hamid Reza Baghani
Affiliation:
Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran
Seyed Rabi Mahdavi*
Affiliation:
Medical Physics Department, Iran University of Medical Sciences, Tehran, Iran
Seyed Mahmoud Reza Aghamiri
Affiliation:
Radiation Medicine Department, Shahid Beheshti University, Tehran, Iran
Mohammad Esmail Akbari
Affiliation:
Cancer Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
*
Correspondence to: Seyed R. Mahdavi, Medical Physics Department, Iran University of Medical Sciences, Tehran 14496141525, Iran. Tel: 982188622647. Fax: 982188622647. E-mail: [email protected]

Abstract

Purpose

The effective source to surface distance (SSDeff) for different combinations of energy/applicator size of the electron beam produced by the light intraoperative accelerator, a mobile dedicated intraoperative radiotherapy accelerator, has been calculated in this study.

Methods

Both ionometric dosimetry and Monte Carlo (MC) simulation were followed to obtain the SSDeff for different combinations of electron energy/applicator size. Simulations were performed using Monte Carlo Nuclear Particles (MCNP) MC code. Measurements were performed by Advance Markus chamber and inside a polymethyl methacrylate slab phantom. Inverse square law method was employed to determine the SSDeff from acquired dosimetry data.

Result

With increasing the applicator diameter at a given energy, SSDeff is also increased. The same result is obtained with increasing the electron beam energy for a given applicator size. The results of MC-based SSDeff for 10 cm diameter reference applicator at different energies were in a good accordance with those obtained by ionometric dosimetry. The maximum and mean differences between the results were 1·1 and 0·6%, respectively.

Conclusions

The results of this study showed that SSDeff of intraoperative electron beam is highly dependent on the applicator size and is a mild function of electron beam energy. These facts are in accordance with those reported for conventional electron beam. The good agreement between the results of MC simulation and ionometric dosimetry confirms the application of MCNP code in modelling of intraoperative electron beam and obtaining the intended parameters.

Type
Original Articles
Copyright
© Cambridge University Press 2016 

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References

1. Veronesi, U, Orecchia, R, Luini, A et al. Full-dose intraoperative radiotherapy with electrons during breast conserving surgery: experience with 590 cases. Ann Surg 2005; 242: 101106.Google Scholar
2. Biggs, P, Willett, C G, Rutten, H et al. Intraoperative electron beam irradiation: physics and techniques. In: Gunderson L L, Willett C G, Calvo F A, Harrison L B (eds) Intraoperative Irradiation: Techniques and Results, 2nd edition. New York, NY: Humana Press, 2011: 5356.Google Scholar
3. Baghani, H R, Aghamiri, S M R, Mahdavi, S R et al. Comparing the dosimetric characteristics of the electron beam from dedicated intraoperative and conventional radiotherapy accelerators. J Appl Clin Med Phys 2015; 16: 6272.Google Scholar
4. Robatjazi, M, Mahdavi, S R, Takavr, A et al. Application of Gafchromic EBT2 film for intraoperative radiation therapy quality assurance. Phys Medica 2015; 31: 314319.Google Scholar
5. Baghani, H R, Aghamiri, S M R, Mahdavi, S R et al. Dosimetric evaluation of Gafchromic EBT2 film for breast intraoperative electron radiotherapy verification. Phys Medica 2015; 31: 3742.Google Scholar
6. Beddar, A S, Biggs, P J, Chang, S et al. Intraoperative radiation therapy using mobile electron linear accelerators: report of AAPM Radiation Therapy Committee Task Group No. 72. Med. Phys 2006; 33: 14761489.Google Scholar
7. Iaccarino, G, Strigari, L, D’Andrea, M et al. Monte Carlo simulation of electron beams generated by a 12 MeV dedicated mobile IORT accelerator. Phys Med Biol 2011; 56: 45794596.CrossRefGoogle ScholarPubMed
8. Rahimzadeh, Z, Mahdavi, S R, Baghani, H R et al. In vivo dosimetry using radiochromic films (EBT-2) during intraoperative radiotherapy. J Radiother Pract 2016; doi:http://dx.doi.org/10.1017/S1460396916000273.CrossRefGoogle Scholar
9. Ciocca, M, Pedroli, G, Orecchia, R et al. Radiation survey around a Liac mobile electron linear accelerator for intraoperative radiation therapy. J Appl Clin Med Phys 2009; 10: 131138.Google Scholar
10. Al Asmary, M A, Ravikumar, M. Position of effective electron source for shielded electron beams from a therapeutic linear accelerator. Pol J Med Phys Eng 2010; 16: 1121.Google Scholar
11. Khan, F M. The Physics of Radiation Therapy, 3rd edition. Philadelphia, PA: Lippincott Williams & Wilkins, 2003: 315317.Google Scholar
12. ICRU. Radiation Dosimetry: Electrons with Initial Energies Between 1 and 50 MeV. Report No. 35. Washington, DC: International Commission on Radiation Units and Measurement, 1984.Google Scholar
13. Cecatti, E R, Goncalves, J F, Cecatti, S G et al. Effect of the accelerator design on the position of the effective electron source. Med Phys 1983; 10: 683686.Google Scholar
14. Jamshidi, A, Kuchnir, F T, Reft, C S. Determination of the source position for the electron beams from a high energy linear accelerator. Med Phys 1986; 13: 942945.Google Scholar
15. Ravindran, B P. A study on virtual source position for electron beams from a Mevatron MD linear accelerator. Phys Med Biol 1999; 44: 13091315.Google Scholar
16. Schroder-Babo, P. Determination of the virtual electron sources of a betatron. Acta Radiol 1983; 364: 710.Google ScholarPubMed
17. Meyer, J, Palta, J, Hogstrom, K. Demonstration of relatively new electron dosimetry measurement techniques on the Mevatron 80. Med Phys 1984; 11: 670677.CrossRefGoogle ScholarPubMed
18. Hogstrom, K R. Evaluation of electron pencil beam dose calculation. Med Phys 1985; 12: 554557.Google Scholar
19. Khan, F M, Sewchand, W, Levitt, S H. Effect of air space on depth dose in electron beam therapy. Radiology 1978; 126: 249251.CrossRefGoogle ScholarPubMed
20. Lamanna, E, Gallo, A, Russo, F et al. Intra-operative radiotherapy with electron beam (Chapter 9) [online]. In: Natanasabapathi G (ed). Modern practices in radiation therapy. Rijeka/Croatia: InTech Open Access Publisher, 2012: 150152.Google Scholar
21.LIAC, the mobile electron accelerator for Intraoperative Radiotherapy (IORT). Technical report. http://www.sordina.com/download/Catalogo_IORT.pdf. Accessed on 27th February 2014.Google Scholar
22. Anna, W R, Przemyslaw, A, Adam, W. Monte Carlo study of a new mobile electron accelerator head for intraoperative radiation therapy(IORT). Prog Nucl Sci Technol 2011; 2: 181186.Google Scholar
23. Strigari, L, Soriani, A, Landoni, V et al. Radiation exposure of personnel during intraoperative radiotherapy (IORT): radiation protection aspects. J Exp Clin Cancer Res 2004; 23: 489494.Google ScholarPubMed
24. Podgorsak, E B. Review of Radiation Oncology Physics: A Handbook for Teachers and Students, 2nd edition. Vienna, Austria: International AtomicEnergy Agency, 2003.Google Scholar
25. Low, D A, Dempsey, J F. Evaluation of the gamma dose distribution comparison method. Med Phys 2003; 30: 24552464.Google Scholar
26.International Atomic Energy Agency. Absorbed dose determination in external beam radiotherapy: an international code of practice for dosimetry based on standards of absorbed dose to water. IAEA TRS-398. Vienna, 2001.Google Scholar
27. Das, I J, Cheng, C W, Watts, R J et al. Accelerator beam data commissioning equipment and procedures: report of the TG-106 of the therapy physics committee of the AAPM. Med Phys 2008; 35: 41864215.Google Scholar
28. Pimpinella, M, Mihailescu, D, Guerra, A et al. Dosimetric characteristics of electron beams produced by a mobile accelerator for IORT. Phys Med Biol 2007; 52: 61976214.CrossRefGoogle ScholarPubMed