Evaluation of Change in Attenuation Coefficient of Cerrobend Block Used for Radiation Protection of Healthy Tissues in Megavoltage Photon Radiation Therapy after Multiple Melting

Document Type : Original Article

Authors

1 Deprtment of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

2 Deprtment of Radiotherapy and Oncology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran

3 Deprtment of Radiotherapy and Oncology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Abstract

Background and Objective: Protecting the vital organs in radiation therapy is one of the most important issues. Cerrobend alloy, the most common material used as the shield, is melted several times and used for different patients. In this study changes in attenuation coefficient of cerrobend due to melting was investigated.
Subjects and Methods: In melting furnace, cerrobend was melted up to nine times and irradiated by Varian accelerator at radiotherapy department of Golestan hospital and the dose was measured by CC-13 ionization chamber with and without cerrobend blocks. The attenuation coefficients of cerrobend blocks were measured for irradiation fields of 6 × 6 cm2 and 10 × 10 cm2 at the photon energies of 6 mv and 18mv and analyzed by statistical methods.
Results: Results of regression analysis with P>0.05, indicated that there was a significant relationship between the attenuation coefficient and frequencies of cerrobend melting: the attenuation coefficient increases with the increasing frequency of cerrobend melting.
Conclusion: Continuous increasing in the frequency of cerrobend melting leads to increase in the attenuation coefficient of cerrobend block, thus cerrobend blocks can be used for patients, safely.

Keywords

References

-Khan FM. The physics of radiation therapy. 4th ed. Philadelphia: Lippincott Williams & Wilkins.2009; 243-52.
2-Muller-Runkel R, Ovadia J, Borger F, Culbert H, Rohowsky B. A shaping device for irregular electron fields for the Therac-20accelerator. Med Phys 1985;12(1):90-2.
3-Henderson SD, Purdy JA, Gerber RL, Mestman SJ. Dosimetry considerations for a lipowitz metal tissue compensator system. Int J Radiat Oncol Biol Phys 1987;13(7):1107- 12.
4-Jordan T, Williams P. The design and performance characteristics of a multileaf collimator. Phys Med Biol 1994;39(2):231-51.
5-Boyer AL, Ochran TG, Nyerick CE, Waldron TJ, Huntzinger CJ. Clinical dosimetry for implementation of a multileaf collimator. Med Phys1992;19(2):1255-61.
6-Bas M, Gursoy O, Alkaya F, Ayar H, Yavuz A. The use of pure lead instead of lipowitz alloy in radiotherapy applications and a newly-developed mold apparatus. East J Med 1999;4(2):73-6.
7-Blackwell CR, Amundson KD. Cadmium free lead alloy for reusable radiotherapy shielding. Med Dosim 1990;15(3):127-9.
8-Iftikhar A, Wazir M, Kakakhail MB, Sbilal A, Amjad H, Khwaja A, et al. Comparison of Lead and Cerrobend Blocks for Incident Photon Flux of 6 and 15 MV X-rays. Iran J Cancer Prev 2011;4(1):10-14.
9-Brezovich IA, Sparks KS, Duan J. A self-correcting method for improving the precision of beam blocks. J Appl Clin Med Phys 2001;2(3):106-13.
10-Ravichandran R,  Binukumar JP, Kannadhasan S. Testicular shield for para-aortic radiotherapy and estimation of gonad doses. Med Phys 2008; 33(4): 158-61.
11-Taherkhani A, Mohammadi M, Saboori MS, Changizi V. Evaluation of the physical characteristic of Cerrobend blocks used for radiation therapy. Iran J Radiat Res 2010;8(2):93-101.
12-Wojcicka JB, Yankelevich R, Werner BL, Lasher DE. Technical note: on Cerrobend shielding for 18–22 MeV electron beams. Med phys 2008;35(10):4625-9.
13-Hall EJ, Giaccia AJ. Radiobiology for the Radiologist. 6th ed. Philadelphia: Lippincott Williams & Wilkins; 2006; 47-81.
14-Ivanova T, Bliznakova K, Malatara G, Kardamakis D, Kolitsi Z, Pallikarakis N. Simulation studies on the effect of absorbers on dose distribution in rotational radiotherapy. Med Phys 2009;25(4):172-80.
Jundishapur Scientific Medical Journal
Volume 13, Issue 3 - Serial Number 90
September and October 2014
Pages 266-274

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History

  • Receive Date: 20 November 2013
  • Revise Date: 06 March 2015
  • Accept Date: 08 April 2014

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