IJMPCERO  Vol.5 No.1 , February 2016
Commissioning of TrueBeamTM Medical Linear Accelerator: Quantitative and Qualitative Dosimetric Analysis and Comparison of Flattening Filter (FF) and Flattening Filter Free (FFF) Beam
Abstract: Motive of the study is to present quantitative and qualitative analysis and comparison of beam data measurement with FF (flattening filter) and FFF (flattening filter free) beam in a Varian TrueBeamTM Medical Linear Accelerator. Critique of beam characterization and evolution of dosimetric properties for 6 MV, 10 MV, 15 MV FF beam and 6 MVFFF, 10 MVFFF FFF beam has been carried out. We performed the comparison of photon beam data for two standard FF photon energy 6 MV, 10 MV verses 6 MVFFF, and 10 MVFFF FFF beam. Determination and comparison of parameter involved PDD (Percentage depth dose), Depth dose profile, Symmetry, Flatness, Quality index, Relative output factor, Penumbra, Transmission factor, DLG (Dosimetric leaf gap), in addition to degree of Un-flatness and off-axis ratio of FFF beam. Outcomes of presenting study had shown that change of various parameters such as Percentage depth dose curves, Shape of the depth dose profile, Transmission, Value of quality index and significant rise in surface dose for FFF in comparison with FF beam. Differences in the output factor at lower and higher field sizes for FFF beam compared to that of FF beam were found. The maximum output factor deviation between 6 MV and 6 MVFFF was found to be 4.55%, whereas in 10 MV and 10 MVFFF was 5.71%. Beam quality TPR20/10 for FFF beam was found to be lesser in magnitude, 5.42% for 6 MVFFF whereas 4.50% for 10 MVFFF compared to 6 MV and 10 MV FF beam respectively. Jaw transmission and interleaf leakage for FFF beam were found to be lesser than FF beam. Also DLG for FFF beam was found to be lesser in magnitude comparable to that of flattened beam. This study is mainly inclined towards evaluation and comparison of the FF and FFF beam. It has been observed that, the outcome of a commissioning beam data generation fully complies with vendor specification and published literature.
Cite this paper: Shende, R. , Gupta, G. , Patel, G. and Kumar, S. (2016) Commissioning of TrueBeamTM Medical Linear Accelerator: Quantitative and Qualitative Dosimetric Analysis and Comparison of Flattening Filter (FF) and Flattening Filter Free (FFF) Beam. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 5, 51-69. doi: 10.4236/ijmpcero.2016.51006.

[1]   Das, I.J., Cheng, C.W., Watts, R.J., Ahnesjö, A., Gibbons, J., Li, X.A., Lowenstein, J., Mitra, R.K., Simon, W.E. and Zhu, T.C. (2008) Accelerator Beam Data Commissioning Equipment and Procedures: Report of the TG-106 of the Therapy Physics Committee of the AAPM. Medical Physics, 35, 4186-4215.

[2]   Nath, R., Biggs, P.J., Bova, F.J., Ling, C.C., Purdy, J.A., van de Geijn, J. and Weinhous, M.S. (1994) AAPM Code of Practice for Radiotherapy Accelerators: Report of AAPM Radiation Therapy Task Group No. 45. Medical Physics, 21, 1093-1121. (AAPM Report No. 47)

[3]   Sahani, G., Sharma, S.D., Sharma, P.K., Deshpande, D.D., Negi, P.S., Sathianarayanan, V.K. and Rath, G.K. (2014) Acceptance Criteria for Flattening Filter-Free Photon Beam from Standard Medical Electron Linear Accelerator: AERB Task Group Recommendations. Journal of Medical Physics, 39, 206-211.

[4]   Khan, F.M. (2003) Physics of Radiation Therapy. 3rd Edition, Chapter No. 11, Lippincott Williams & Wilkins.

[5]   Khan, F.M. (2003) Physics of Radiation Therapy. 3rd Edition, Chapter No. 10, Lippincott Williams & Wilkins.

[6]   Musolino, S.V. (2000) Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water. Health Physics, 81, 592-593. (IAEA TRS-398)

[7]   Boyer, A., Biggs, P., Galvin, J., Klein, E., LoSasso, T., Low, D., Mah, K. and Yu, C. (2001) Basic Applications of Multileaf Collimator: Report of Task Group No. 50 Radiation Therapy Committee. American Association of Physicists in Medicine (AAPM TG-50, 10) (AAPM Report No. 72).

[8]   Szpala, S., Cao, F. and Kohli, K. (2014) On Using the Dosimetric Leaf Gap to Model the Rounded Leaf Ends in VMAT/RapidArc Plans. Journal of Applied Clinical Medical Physics, 15, 4484.

[9]   Dosimetric Leaf Gap Measurement, Procedure Recommended by Varian Medical System. Eclipse 10 Inverse Planning Administration and Physics rev. 6.1.1.

[10]   Gloria, P. (2013) Commissioning Measurements for Photon Beam Data on Three TrueBeam Linear Accelerators, and Comparison with Trilogy and Clinac 2100 Linear Accelerators. Journal of Applied Clinical Medical Physics, 14, 4077.

[11]   Chang, Z., Wu, Q.W., Adamson, J., Ren, L., Bowsher, J.E., Yan, H., Thomas, A. and Yin, F.-F. (2012) Commissioning and Dosimetric Characteristics of TrueBeam System: Composite Data of Three TrueBeam Machines. Medical Physics, 39, 6981-7018.

[12]   Georg, D., Knöös, T. and McClean, B. (2011) Current Status and Future Perspective of Flattening Filter Free Photon Beams. Medical Physics, 38, 1280-1293.

[13]   Ashokkumar, S., Nambi Raj, N.A., Sinha, S.N., Yadav, G., Thiyagarajan, R., Raman, K. and Mishra, M.B. (2014) Comparison of Head Scatter Factor for 6MV and 10MV Flattened (FB) and Unflattened (FFF) Photon Beam Using Indigenously Designed Columnar Mini Phantom. Journal of Medical Physics, 39, 184-191.