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Dosimetric evaluation of a novel electron–photon mixed beam, produced by a medical linear accelerator

Published online by Cambridge University Press:  10 January 2018

Navid Khaledi ,
Dariush Sardari ,
Mohammad Mohammadi ,
Ahmad Ameri  and
Nick Reynaert
Navid Khaledi
Affiliation:
Department of Clinical Oncology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Dariush Sardari
Affiliation:
Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
Mohammad Mohammadi
Affiliation:
Department of Radiation Oncology, Royal Adelaide Hospital, Adelaide, Australia
Ahmad Ameri*
Affiliation:
Department of Clinical Oncology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Nick Reynaert
Affiliation:
Medical Physics Department, Centre Oscar Lambret, Lille, France
*
Correspondence to: Ahmad Ameri, Department of Clinical Oncology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Tel: +98 21 73430000. E-mail: a_ameri@sbmu.ac.ir
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Abstract

Aim

This study deals with the characteristics of simultaneous photon and electron beams in homogenous and inhomogeneous phantoms by experimental and Monte Carlo dosimetry, for therapeutic purposes. Materials and methods: Both 16 and 20 MeV high-energy electron beams were used as the original beam to strike perforated lead sheets to produce the mixed beam. The dosimetry results were achieved by measurement in an ion chamber in a water phantom and film dosimetry in a Perspex nasal phantom, and then compared with those calculated through a simulation approach. To evaluate two-dimensional dose distribution in the inhomogeneous medium, the dose–area histogram was obtained.

Results

The highest percentage of photon contribution in mixed beam was found to be 36% for 2-mm thickness of lead layer with holes diameter of 0·2 cm for a 20 MeV primary electron energy. For small fields, the percentage depth dose parameters variations were found to be similar to pure electron beam within ±2%. The most feasible flatness in beam profile was 11% for pure electron and 7% for the mixed beam. Penumbra changes as function of depth was about ten times better than in pure electron field.

Conclusions

The results present some dosimetric advantages that can make this study a platform for the production of simultaneous mixed beams in future linear accelerators (LINACs), which through redesign of the LINAC head, which could lead to setup error reduction and a decrease of intra-fractional tumour cells repair.

Keywords

electron beamfilm dosimetrymixed beamphoton beamradiation therapy
Type
Original Article
Information
Journal of Radiotherapy in Practice , Volume 17 , Issue 3 , September 2018 , pp. 319 - 331
Copyright
© Cambridge University Press 2018 

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References

1. Korevaar, E W, Heijmen, B J, Woudstra, E, Huizenga, H, Brahme, A. Mixing intensity modulated electron and photon beams: combining a steep dose fall-off at depth with sharp and depth-independent penumbras and flat beam profiles. Phys Med Biol 1999; 44: 21–25.Google Scholar
2. Krayenbuehl, J, Oertel, S, Davis, J B, Ciernik, I F. Combined photon and electron three-dimensional conformal versus intensity-modulated radiotherapy with integrated boost for adjuvant treatment of malignant pleural mesothelioma after pleuropneumonectomy. Int J Radiat Oncol Biol Phys 2007; 69: 1593–1599.Google Scholar
3. Kwan, W, Wilson, D, Moravan, V. Radiotherapy for locally advanced basal cell and squamous cell carcinomas of the skin. Int J Radiat Oncol Biol Phys 2004; 60: 406–411.Google Scholar
4. Li, J G, Williams, S S, Goffinet, D R, Boyer, A L, Xing, L. Breast-conserving radiation therapy using combined electron and intensity-modulated radiotherapy technique. Radiother Oncol 2000; 56: 65–71.Google Scholar
5. Korevaar, E W, van Vliet, R J, Woudstra, E, Heijmen, B J, Huizenga, H. Sharpening the penumbra of high energy electron beams with low weight narrow photon beams. Radiother Oncol 1998; 48: 213–220.Google Scholar
6. Ma, C, Ding, M, Li, J, Lee, M, Pawlicki, T, Deng, J. A comparative dosimetric study on tangential photon beams, intensity-modulated radiation therapy (IMRT) and modulated electron radiotherapy (MERT) for breast cancer treatment. Phys Med Biol 2003; 48: 90–99.Google Scholar
7. Mosalaei, H, Karnas, S, Shah, S, Van Doodewaard, S, Foster, T, Chen, J. The use of intensity-modulated radiation therapy photon beams for improving the dose uniformity of electron beams shaped with MLC. Med Dosim 2012; 37: 76–83.Google Scholar
8. Mu, X, Olofsson, L, Karlsson, M, Sjögren, R, Zackrisson, B. Can photon IMRT be improved by combination with mixed electron and photon techniques? Acta Oncol 2004; 43: 727–735.Google Scholar
9. Khan, F M. The physics of radiation therapy. Philadelphia: Lippincott Williams & Wilkins Philadelphia, 2014.Google Scholar
10. Hogstrom, K R, Antolak, J, Kudchadker, R, Ma, C, Leavitt, D. Modulated electron therapy. In: Intensity modulated radiation therapy, the state of the art: proceedings of the 2003 AAPM summer. School Madison, WI: Medical Physics Publishing, 2003: 749–786.Google Scholar
11. Yeboah, C, Sandison, G, Moskvin, V. Optimization of intensity-modulated very high energy (50–250 MeV) electron therapy. Phys Med Biol 2002; 47: 1285–1301.Google Scholar
12. Hogstrom, K R, Almond, P R. Review of electron beam therapy physics. Phys Med Biol 2006; 51: R455–R489.Google Scholar
13. Van Battum, L J, Huizenga, H. Film dosimetry of clinical electron beams. Int J Radiat Oncol Biol Phys 1990; 18: 69–76.Google Scholar
14. Khaledi, N, Arbabi, A, Sardari, D et al. Monte Carlo investigation of the effect of small cutouts on beam profile parameters of 12 and 14 MeV electron beams. Radiat Meas 2013; 51: 48–54.Google Scholar
15. Xiong, W, Li, J, Chen, L et al. Optimization of combined electron and photon beams for breast cancer. Phys Med Biol 2004; 49: 1973–1989.Google Scholar
16. Palma, B A, Sánchez, A U, Salguero, F J et al. Combined modulated electron and photon beams planned by a Monte-Carlo-based optimization procedure for accelerated partial breast irradiation. Phys Med Biol 2012; 57: 1191.Google Scholar
17. Mueller, S, Fix, M, Joosten, A et al. Simultaneous optimization of photons and electrons for mixed beam radiotherapy. Phys Med Biol 2017; 62: 5840–5860.Google Scholar
18. Eldib, A, Jin, L, Li, J, Ma, C C. Feasibility of replacing patient specific cutouts with a computer-controlled electron multileaf collimator. Phys Med Biol 2013; 58: 53–56.Google Scholar
19. Khaledi, N, Arbabi, A, Sardari, D, Mohammadi, M, Ameri, A. Simultaneous production of mixed electron–photon beam in a medical LINAC: a feasibility study. Phys Med 2015; 31: 391–397.Google Scholar
20. Andreo, P, Burns, D T, Hohlfeld, K et al. Absorbed dose determination in external beam radiotherapy: an international code of practice for dosimetry based on standards of absorbed dose to water. IAEA Technical Report Series. Vienna (Austria): IAEA, 2000.Google Scholar
21. Turian, J V, Smith, B D, Bernard, D A, Griem, K L, Chu, J C. Monte Carlo calculations of output factors for clinically shaped electron fields. J Appl Clin Med Phys 2004; 5: 42–63.Google Scholar
22. Hogstrom, K R, Mills, M D, Eyer, J A et al. Dosimetric evaluation of a pencil-beam algorithm for electrons employing a two-dimensional heterogeneity correction. Int J Radiat Oncol Biol Phys 1984; 10: 561–569.Google Scholar
23. Mah, E, Antolak, J, Scrimger, J W, Battista, J J. Experimental evaluation of a 2D and 3D electron pencil beam algorithm. Phys Med Biol 1989; 34: 79–83.Google Scholar
24. Reynaert, N, Van Der Marck, S, Schaart, D et al. Monte Carlo treatment planning for photon and electron beams. Radiat Phys Chem 2007; 76: 643–686.Google Scholar
25. Sheikh-Bagheri, D, Rogers, D. Monte Carlo calculation of nine megavoltage photon beam spectra using the BEAM code. Med Phys 2002; 29: 39–41.Google Scholar
26. Hu, W, Xu, A, Li, G, Zhang, Z, Housley, D, Ye, J. A real-time respiration position based passive breath gating equipment for gated radiotherapy: a preclinical evaluation. Med phys 2012; 39: 1345–1350.Google Scholar
27. Renaud, M A, Serban, M, Seuntjens, J. On mixed electron‐photon radiation therapy optimisation using the column generation approach. Med Phys 2017; 44: 4287–4298.Google Scholar
28. Blasi, O, Fontenot, J D, Fields, R S, Gibbons, J P, Hogstrom, K R. Preliminary comparison of helical tomotherapy and mixed beams of unmodulated electrons and intensity modulated radiation therapy for treating superficial cancers of the parotid gland and nasal cavity. Radiat Oncol 2011; 6: 178.Google Scholar
29. Arbea, L, Ramos, L I, Martínez-Monge, R, Moreno, M, Aristu, J. Intensity-modulated radiation therapy (IMRT) vs. 3D conformal radiotherapy (3DCRT) in locally advanced rectal cancer (LARC): dosimetric comparison and clinical implications. Radiat Oncol 2010; 5: 17.Google Scholar