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Radiation dose distribution under the area protected using a Cerrobend block during external beam radiotherapy: a film study

Published online by Cambridge University Press:  03 April 2014

Mohammad Mohammadi ,
Amir Taherkhani  and
Mohmmadsaeed Saboori
Mohammad Mohammadi*
Affiliation:
Department of Medical Physics, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Department of Medical Physics, Royal Adelaide Hospital, Adelaide, 5000 South Australia, Australia
Amir Taherkhani
Affiliation:
Department of Proteomics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Department of Microbiology, Islamic Azad University, Hamadan, Iran
Mohmmadsaeed Saboori
Affiliation:
University Hospitals of Erlangen, Radiation Oncology, Erlangen, Germany
*
Correspondence to: Mohammad Mohammadi, Department of Medical Physics, Faculty of Medicine, Hamadan University of Medical Sciences, 65178-38678 Hamadan, Iran. Tel: +98 8381037; Fax: +98 8381017. E-mail: Mohammadi@umsha.ac.ir
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Abstract

Background

In radiation therapy, to spare normal surrounding tissues, either Multileaf Collimators or Cerrobend blocks are used.

Purpose

The current study focuses on the relative dose distribution under the areas protected by Cerrobend blocks.

Materials and methods

A dual-energy linear accelerator and a Cobalt-60 machine were utilised as radiation sources. Several blocks were designed using commercially available materials to shield radiation fields. The relative dose distribution was then evaluated using extended dose range 2 films.

Results

Results showed that the dose distribution under protected areas depends on several parameters including the width and height of protecting blocks, incident photon beam energy, radiation field size and source to surface distance. An increase in Cerrobend block height from 80 to 95 mm significantly decreases the dose at the protected areas.

Conclusion

An increase in the block width and photon energy decreases the relative dose deposition at the protected area. However, electron and neutron contaminations should also be taken into consideration.

Keywords

Cerrobend blocksdose distributionfilm dosimetryradiation protection
Type
Original Articles
Information
Journal of Radiotherapy in Practice , Volume 13 , Issue 4 , December 2014 , pp. 456 - 464
Copyright
Copyright © Cambridge University Press 2014 

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References

1. Boyer, A, Ochran, T, Nyerick, C, Waldron, T, Huntzinger, C. Clinical dosimetry for implementation of a multileaf collimator. Med Phys 1992; 19 (5): 1255–1261.CrossRefGoogle ScholarPubMed
2. Cheng, C, Wong, J, Ndlovu, A, Das, I, Schiff, P, Uematsu, M. Dosimetric evaluation and clinical application of virtual mini-multileaf collimator. Am J Clin Oncol 2003; 26 (3): e37–e44.CrossRefGoogle ScholarPubMed
3. Palta, J, Yeung, D, Frouhar, V. Dosimetric consideration for a multileaf collimator system. Med Phys 1996; 23 (7): 1219–1224.CrossRefGoogle ScholarPubMed
4. Stasi, M, Baiotto, B, Palamara, F, Gabriele, P, Scielzo, G. Dosimetric characterization of a multileaf collimator. Radiol Med (Torino) 1999; 97 (5): 382–388.Google ScholarPubMed
5. AAPM Radiation Therapy Committee and Boyer A. Basic Application of Multileaf Collimators, Task Group 50. American Association of Physicists in Medicine (AAPM) 2001.Google Scholar
6. Dawson, J, Kahler, D, McDonald, B, Kopecky, W, Gu, J. Surface and percentage depth doses for secondary blocking using a multileaf collimator and cerrobend-alloy blocks. Radiother Oncol 1997; 42 (3): 285–288.CrossRefGoogle ScholarPubMed
7. Rieger, J, Mehta, M, Paliwal, B, Kubsad, S. Weight consideration in the use of cerrobend beam blocks. Med Dosim 1992; 17 (3): 141–143.CrossRefGoogle ScholarPubMed
8. Khan, F M. The physics of radiation therapy, 3rd edition. Philadelphia: Lippincott Williams & Wilkins, 1993.Google Scholar
9. Taherkhani, A, Mohammadi, M, Saboori, M, Changizi, V. Evaluation of the physical characteristic of Cerrobend blocks used for radiation therapy. Int J Radiat Res 2010; 8 (2): 93–101.Google Scholar
10. Galvin, J M, Smith, A R, Lally, B. Characterization of a multi-leaf collimator system. Int J Radiat Oncol Biol Phys 1993; 25 (2): 181–192.CrossRefGoogle ScholarPubMed
11. Jordan, T, Williams, P. The design and performance characteristics of a multileaf collimator. Phys Med Biol 1994; 39 (2): 231–251.CrossRefGoogle ScholarPubMed
12. Butson, M, Yu, P, Cheung, T. Rounded end multi-leaf penumbral measurements with radiochromic film. Phys Med Biol 2003; 48 (17): N247–N252.CrossRefGoogle ScholarPubMed
13. Klein, E, Low, D. Interleaf leakage for 5 and 10 mm dynamic multileaf collimation systems incorporating patient motion. Med Phys 2001; 28 (8): 1703–1710.CrossRefGoogle ScholarPubMed
14. Chow, L, Seguin, M, Alexander, A. Dosimetric effect of collimating jaws for small multileaf collimated fields. Med Phys 2005; 32 (3): 759–765.CrossRefGoogle ScholarPubMed
15. Huq, M S, Yu, Y, Chen, Z P, Suntharalingam, N. Dosimetric characteristics of a commercial multileaf collimator. Med Phys 1995; 22 (2): 241–247.CrossRefGoogle ScholarPubMed
16. Klein, E, Harms, W, Low, D, Willcut, V, Purdy, J. Clinical implementation of a commercial multileaf collimator: dosimetry, networking, simulation, and quality assurance. Int J Radiat Oncol Biol Phys 1995; 33 (5): 1195–1208.CrossRefGoogle ScholarPubMed
17. Huq, M S, Das, I J, Steinberg, T, Galvin, J M. A dosimetric comparison of various multileaf collimators. Phys Med Biol 2002; 47 (12): N159–N170.CrossRefGoogle ScholarPubMed
18. Balog, J P, Mackie, T R, Wenman, D L, Glass, M, Fang, G, Pearson, D. Multileaf collimator interleaf transmission. Med Phys 1999; 26 (2): 176–186.CrossRefGoogle ScholarPubMed
19. Pasquino, M, Casanova Borca, V, Tofani, S. Physical-dosimetric characterization of a multi-leaf collimator system for clinical implementation in conformational radiotherapy. Radiol Med (Torino) 2001; 101 (3): 187–192.Google ScholarPubMed
20. Zhu, Y, Boyer, A L, Desobry, G E. Dose distributions of x-ray fields as shaped with multileaf collimators. Phys Med Biol 1992; 37 (1): 163–174.CrossRefGoogle Scholar
21. Galvin, J M, Leavitt, D D, Smith, A A. Field edge smoothing for multileaf collimators. Int J Radiat Oncol Biol Phys 1996; 35 (1): 89–94.CrossRefGoogle ScholarPubMed
22. Stasi, M, Baiotto, B, Palamara, F, Gabriele, P, Scielzo, G. Effective penumbra and scalloping effect: a dosimetric study in multifield radiotherapy with multileaf collimator for prostate cancer treatment. Tumori 2001; 87 (1): 30–35.CrossRefGoogle ScholarPubMed
23. Cheng, C W, Das, I J, Steinberg, T. Role of multileaf collimator in replacing shielding blocks in radiation therapy. Int J Cancer 2001; 96 (6): 385–395.CrossRefGoogle ScholarPubMed
24. Hogstrom, K R, Boyd, R A, Antolak, J A, Svatos, M M, Faddegon, B A, Rosenman, J G. Dosimetry of a prototype retractable eMLC for fixed-beam electron therapy. Med Phys 2004; 31 (3): 443–462.CrossRefGoogle ScholarPubMed
25. Liu, Y, Shi, C, Tynan, P, Papanikolaou, N. Dosimetric characteristics of dual-layer multileaf collimation for small-field and intensity-modulated radiation therapy applications. J Appl Clin Med Phys 2008; 9 (2): 2709.CrossRefGoogle ScholarPubMed
26. Xu, M M, Sethi, A, Glasgow, G P. Dosimetry of small circular fields for 6-MeV electron beams. Med Dosim 2009; 34 (1): 51–56.CrossRefGoogle ScholarPubMed
27. Frazier, A, Du, M, Wong, J, et al. Dosimetric evaluation of the conformation of the multileaf collimator to irregularly shaped fields. Int J Radiat Oncol Biol Phys 1995; 33 (5): 1229–1238.CrossRefGoogle ScholarPubMed
28. Wojcicka, J B, Yankelevich, R, Werner, B L, Lasher, D E. Technical note: on cerrobend shielding for 18-22 MeV electron beams. Med Phys 2008; 35 (10): 4625–4629.CrossRefGoogle ScholarPubMed
29. Steel, J, Stewart, A, Satory, P. Matching extended-SSD electron beams to multileaf collimated photon beams in the treatment of head and neck cancer. Med Phys 2009; 36 (9): 4244–4249.CrossRefGoogle ScholarPubMed
30. Arunkumar, T, Supe, SS, Ravikumar, M, Sathiyan, S, Ganesh, M. Electron beam characteristics at extended source-to-surface distances for irregular cut-outs. J Med Phys 2010; 35 (4): 207–214.Google ScholarPubMed
31. Khaledy, N, Arbabi, A, Sardari, D. The effects of cutouts on output, mean energy and percentage depth dose of 12 and 14 MeV electrons. J Med Phys 2011; 36 (4): 213–219.CrossRefGoogle ScholarPubMed
32. Brualla, L, Zaragoza, F J, Sempau, J, Wittig, A, Sauerwein, W. Electron irradiation of conjunctival lymphoma-Monte Carlo simulation of the minute dose distribution and technique optimization. Int J Radiat Oncol Biol Phys 2012; 83 (4): 1330–1337.CrossRefGoogle ScholarPubMed
33. Blackwell, C R, Amundson, K D. Cadmium free lead alloy for reusable radiotherapy shielding. Med Dosim 1990; 15 (3): 127–129.CrossRefGoogle ScholarPubMed
34. Dogan, N, Leybovich, L B, Sethi, A. Comparative evaluation of Kodak EDR2 and XV2 films for verification of intensity modulated radiation therapy. Phys Med Biol 2002; 47 (22): 4121–4130.CrossRefGoogle ScholarPubMed
35. Gerbi, B J, Dimitroyannis, D A. The response of Kodak EDR2 film in high-energy electron beams. Med Phys 2003; 30 (10): 2703–2705.CrossRefGoogle ScholarPubMed
36. Zhu, X, Jursinic, P, Grimm, D, Lopez, F, Rownd, J, Gillin, M. Evaluation of Kodak EDR2 film for dose verification of intensity modulated radiation therapy delivered by a static multileaf collimator. Med Phys 2002; 29 (8): 1687–1692.CrossRefGoogle ScholarPubMed
37. Mohammadi, M, Bezak, E, Reich, P. The use of extended dose range film for dosimetric calibration of a scanning liquid-filled ionization chamber electronic portal imaging device. J Appl Clin Med Phys 2007; 8 (1): 69–84.CrossRefGoogle Scholar
38. Devic, S, Seuntjens, J, Shanm, E, et al. Precise radiochromic film dosimetry using a flat-bed document scanner. Med Phys 2005; 32 (7): 2245–2253.CrossRefGoogle ScholarPubMed
39. Bucciolini, M, Buonamici, F, Casati, M. Verification of IMRT fields by film dosimetry. Med Phys 2004; 31 (1): 161–168.CrossRefGoogle ScholarPubMed
40. Esthappan, J, Mutic, S, Harms, W B, Dempsey, J F, Low, D A. Dosimetry of therapeutic photon beams using an extended dose range film. Med Phys 2002; 29 (10): 2438–2445.CrossRefGoogle ScholarPubMed
41. Burch, S, Kearfott, K, Trueblood, J, Sheils, W, Yoe, J, Wang, C. A new approach to film dosimetry for high energy photon beams: lateral scatter filtering. Med Phys 1997; 24 (5): 83–775.CrossRefGoogle ScholarPubMed
42. IEC, IEC 60976: Medical electron accelerators-functional performance characteristics, International Electromechanical Commisions. IEC publication 967. Geneva: International Electromechanical Commisions, 1989.Google Scholar