Dosimetric Evaluation of Heterogeneities in Small Circular Fields of 6 MV Photon Beams with EBT2 and EDR2 Films: Comparison with Monte Carlo Calculation

Ali Mohammad; Hassan A. Nedaie; Mehran YarAhmadi; Nooshin Banaee; Mansour Naderi; Zohre Tizmaghz

doi:10.4236/jmp.2014.516162

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Journal of Modern Physics > Vol.5 No.16, October 2014

Dosimetric Evaluation of Heterogeneities in Small Circular Fields of 6 MV Photon Beams with EBT2 and EDR2 Films: Comparison with Monte Carlo Calculation ()

Ali Mohammad¹, Hassan A. Nedaie^1*, Mehran YarAhmadi², Nooshin Banaee³, Mansour Naderi¹, Zohre Tizmaghz¹

¹Radiotherapy Oncology Department, Cancer Research Centre, Cancer Institute, Tehran University of Medical Sciences, Tehran, Iran.
²Department of Medical Physics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran.
³Young Researchers and Elites Club, Science and Research Branch, Islamic Azad University, Tehran, Iran.

DOI: 10.4236/jmp.2014.516162 PDF HTML XML 3,283 Downloads 3,691 Views Citations

Abstract

The influence of dose variation due to heterogeneities in narrow photon beams used in stereotactic radiosurgery has been investigated. Since the lateral electronic disequilibrium and existence of steep dose gradients in small fields and the presence of heterogeneities can intensify these problems, in this study the effects of heterogeneities on 6 MV small photon beams produced by circular cone collimators with 5, 10, 15, 20 and 30 mm diameters are investigated. The heterogeneities include 3 cm Cork with density of 0.2 g/cm³ instead of lung and 3 cm Polytetrafluoroethylene (P.T.F.E) with density of 2.2 g/cm³ as bone. The measurements were carried out with EBT2 gafchromic and EDR2 radiographic films. Simulation was done by MCNP Monte Carlo Code (MCNP5). The depth dose curves in heterogeneous phantom were compared with homogeneous phantom. A good agreement was obtained within film and Monte Carlo calculations in presence of low density heterogeneity and also in the presence of high density heterogeneity. Monte Carlo results showed good agreement after stopping power correction.

Keywords

Stereotactic Radiosurgery, Heterogeneities, Film Dosimetry, Monte Carlo Calculation

Share and Cite:

Mohammad, A. , Nedaie, H. , YarAhmadi, M. , Banaee, N. , Naderi, M. and Tizmaghz, Z. (2014) Dosimetric Evaluation of Heterogeneities in Small Circular Fields of 6 MV Photon Beams with EBT2 and EDR2 Films: Comparison with Monte Carlo Calculation. Journal of Modern Physics, 5, 1608-1616. doi: 10.4236/jmp.2014.516162.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Podgorsak, B., Pike, G.B., Pla, M., Olivier, A. and Souhami, L. (1990) Radiotherapy and Oncology, 17, 349-358. http://dx.doi.org/10.1016/0167-8140(90)90008-K
[2]	Wu, A., Zwicker, R.D., Kalend, A.M. and Zheng, Z. (1993) Medical Physics, 20, 777. http://dx.doi.org/10.1118/1.597032
[3]	Bjarngard, B.E., Tsai, J.S. and Rice, R.K. (1990) Medical Physics, 17, 794. http://dx.doi.org/10.1118/1.596475
[4]	Rice, R.K., Hansen, J.L., Svensson, G.K. and Siddon, R.L. (1987) Physics in Medicine and Biology, 32, 1087-1099. http://dx.doi.org/10.1088/0031-9155/32/9/002
[5]	Rustgi, SN. and Frye, D.M. (1995) Medical Physics, 22, 2117-2121. http://dx.doi.org/10.1118/1.597655
[6]	Westermark, M., Arndt, J., Nilsson, B. and Brahme, A. (2000) Physics in Medicine and Biology, 45, 685-702. http://dx.doi.org/10.1088/0031-9155/45/3/308
[7]	Martens, C., De Wagter, C. and De Neve, W. (2000) Physics in Medicine and Biology, 45, 2519-2530. http://dx.doi.org/10.1088/0031-9155/45/9/306
[8]	Verhaegen, F., Das, I.J. and Palmans, H. (1998) Physics in Medicine and Biology, 43, 2755-2768. http://dx.doi.org/10.1088/0031-9155/43/10/006
[9]	Rustgi, S.N., Rustgi, A.K., Jiang, S.B. and Ayyangar, KM. (1998) Physics in Medicine and Biology, 43, 3509-3518. http://dx.doi.org/10.1088/0031-9155/43/12/009
[10]	Ahn, Y.C., Lee, K.C., Kim, D.Y., Huh, S.J., Yeo, I.H., Lim, D.H., Kim, M.K., Shin, K.H., Park, S. and Chang, S.H. (2000) International Journal of Radiation Oncology · Biology · Physics, 48, 501-505. http://dx.doi.org/10.1016/S0360-3016(00)00612-X
[11]	Cheung, J.Y., Yu, K.N., Yu, C.P. and Ho, R.T. (2001) Applied Radiation and Isotopes, 54, 461-465. http://dx.doi.org/10.1016/S0969-8043(00)00283-9
[12]	Jones, A.O., Das, I.J. and Jones Jr., F.L. (2003) Medical Physics, 30, 296-300. http://dx.doi.org/10.1118/1.1539040
[13]	Carrasco, P., Jornet, N., Duch, M.A., Panettieri, V., Weber, L., Eudaldo, T., Ginjaume, M. and Ribas, M. (2007) Medical Physics, 34, 3323-3333. http://dx.doi.org/10.1118/1.2750972
[14]	Klein, E.E., Chin, L.M., Rice, R.K. and Mijnheer, B.J. (1993) International Journal of Radiation Oncology, Biology, Physics, 27, 419-427.
[15]	Jones, A.O. and Das, I.J. (2005) Medical Physics, 32, 766-776. http://dx.doi.org/10.1118/1.1861154
[16]	Pappas, E., Maris, T.G., Zacharopoulou, F., Papadakis, A., Manolopoulos, S., Green, S. and Wojnecki, C. (2008) Medical Physics, 35, 4640-4648. http://dx.doi.org/10.1118/1.2977829
[17]	Dogan, N., Leybovich, L.B. and Sethi, A. (2002) Physics in Medicine and Biology, 47, 4121-4130. http://dx.doi.org/10.1088/0031-9155/47/22/314
[18]	Shi, C., Papanikolaou, N., Yan, Y., Weng, X. and Jiang, H. (2006) Journal of Applied Clinical Medical Physics, 7, 1-8.
[19]	Siebers, J.V., Keall, P.V., Nahum, A.E. and Mohan, R. (2000) Physics in Medicine and Biology, 45, 983-995. http://dx.doi.org/10.1088/0031-9155/45/4/313
[20]	AAPM Report (2004) Task Group 65. Tissue Inhomogeneity Corrections for Megavoltage Photon Beams. The American Association of Physicists in Medicine, No. 85, Madison.