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Installation and Commissioning of TrueBeamTM SVC 3. o Medical Linear Accelerator: An empirical measurement and comparative analysis of comprehensive Dosimetric parameters for flattened and unflattened photon beams
Corresponding Author(s) : A. Saravana Kumar
International Journal of Allied Medical Sciences and Clinical Research,
Vol. 13 No. 3 (2025): 2025 Volume -13 - Issue 3
Abstract
This study aims to present a report on the commissioning results of the Varian TrueBeamTMSVC Medical Linear Accelerator with available Flattening filter (FF) and Flattening filter free (FFF) photon beams and to compare their dosimetric differences and advantages. This study intends to benefit medical physicists and biomedical engineers during installation and commissioning. All evaluations followed TG-106 guidelines and regulations from the Atomic Energy regulatory board. Determination and comparison of parameters 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 the degree of Un-flatness and the off-axis ratio of and mechanical test such as Gantry, collimator, couch isocentric check. The 6MVFFF and 10MVFFF beams had the same average energy as the flattened beams and exhibited fewer PDD differences with varying field sizes. The depth of maximum dose (Dmax) was greater for FFF beams across all field sizes compared to their flattened beam counterparts. The symmetry values were almost identical while the flatness values of 6 MV FFF and 10 MV FFF normalized profiles were expected to be higher than the corresponding flattened beams. The surface doses for all beams increased linearly with the field size. For field sizes up to 10 ×10cm2, the 6MVFFF and 10MVFFF beams exhibited increased surface doses compared to the flattened beams, whereas for larger fields, the surface doses were lower. Additionally, both FFF beams had reduced average MLC transmissions in comparison to the flattened beams.
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- Smathers, J.B., 2003. The physics of radiation therapy. In: Khan, Faiz M. (Ed.), J. Appl. Clin. Med. Phys.. . third ed., vol. 4, pp. 382–383. http://dx.doi.org/10.1120/jacmp.v4i4.2507.
- Mesbahi, A., 2007. Dosimetric characteristics of unflattened 6 MV photon beams of a clinical linear accelerator: a Monte Carlo study. Appl. Radiat. Isot. 65, 1029–1036. http://dx.doi.org/10.1016/j. apradiso.2007.04.023.
- Tsiamas, P., Sajo, E., Cifter, F., Theodorou, K., Kappas, C., Makrigiorgos, M., Marcus, K., Zygmanski, P., 2014. Beam quality and dose perturbation of 6 MV flattening-filter-free linac. Phys. Med. 30, 47–56. http://dx.doi.org/10.1016/j.ejmp.2013.02.004.
- Ponisch, F., Titt, U., Vassiliev, O.N., Kry, S.F., Mohan, R., 2006. Properties of unflattened photon beams shaped by a multileaf collimator. Med. Phys. 33, 1738–1746. http://dx.doi.org/10.1118/ 1.2201149
- Klein EE, Hanley J, Bayouth J, et al. Task Group 142 report: quality assurance of medical accelerators. Med Phys. 2009;36(9):4197–212.
- I. J. Das, C.-W. Cheng, R. J. Watts, A. Ahnesjo, J. Gibbons, X. A. Li, J. Lowenstein, R. K. Mitra, W. E. Simon, and T. C. Zhu, “Accelerator beam data commissioning equipment and procedures: Report of the TG-106 of the Therapy Physics Committee of the AAPM,” Med. Phys. 35, 4186–4215 (2008)
- Sievinen J, Ulmer W, Kaissl W. AAA photon dose calculation model in Eclipse. Palo Alto (CA): Varian Medical Systems; 2005. p. 118.
- Musolino SV. Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water; Technical Reports Series No. 398. Health Physics. 2001 Nov 1;81(5):592-3.
- Almond PR, Biggs PJ, Coursey BM, Hanson WF, Huq MS, Nath R, et al. AAPM's TG‐51 protocol for clinical reference dosimetry of high‐energy photon and electron beams. Medical physics. 1999 Sep 1;26(9):1847-70.
- International Electrotechnical Commission. Medical electrical equipment. Part 2: Particular requirements for the safety of gamma beam therapy equipment. IEC 60601-2-11. Geneva, Switzerland: IEC; 1987.
- TRS-483.
- Yao W, Farr JB. Determining the optimal dosimetric leaf gap setting for rounded leaf-end multileaf collimator systems by simple test fields. J Appl Clin Med Phys. 2015;16(4):65-77.
- Sahani G, Sharma SD, Sharma PD, Deshpande DD, Negi PS, SathianarayananVK , et al. Acceptance criteria for flattening filter-free photon beam from standard medical electron linear accelerator: AERB task group recommendations, Journal of Medical Physics/Association of Medical Physics of India. 2014 Oct;39(4) 206.
- Karthick Raj Mani, Md Anisuzzaman Bhuiyan, Md shakilur Rahman, S.M Azharur Islam. Open dosimetriccharacteristcs of True Beam medical linear accelerator with flattening filter (WFF) and flattening filter free (FFF) beam. Polish Journal of Medical Physics and Engineering 2018:24(2):79-89.
- TG 119 IMRT Commissioning Tests Instructions for Planning, Measurement, and Analysis Version 10/21/2009. doi: org/10.1118/1.3238104
- Pichandi A, Ganeshb KM, Jerina A, Balaji K, Kilaraa G. Analysis of physical parameters and determination of inflection point for flattening filter free beams in medical linear accelerator. Rep Fract Oncol Radiother2014;19:322 31
References
Smathers, J.B., 2003. The physics of radiation therapy. In: Khan, Faiz M. (Ed.), J. Appl. Clin. Med. Phys.. . third ed., vol. 4, pp. 382–383. http://dx.doi.org/10.1120/jacmp.v4i4.2507.
Mesbahi, A., 2007. Dosimetric characteristics of unflattened 6 MV photon beams of a clinical linear accelerator: a Monte Carlo study. Appl. Radiat. Isot. 65, 1029–1036. http://dx.doi.org/10.1016/j. apradiso.2007.04.023.
Tsiamas, P., Sajo, E., Cifter, F., Theodorou, K., Kappas, C., Makrigiorgos, M., Marcus, K., Zygmanski, P., 2014. Beam quality and dose perturbation of 6 MV flattening-filter-free linac. Phys. Med. 30, 47–56. http://dx.doi.org/10.1016/j.ejmp.2013.02.004.
Ponisch, F., Titt, U., Vassiliev, O.N., Kry, S.F., Mohan, R., 2006. Properties of unflattened photon beams shaped by a multileaf collimator. Med. Phys. 33, 1738–1746. http://dx.doi.org/10.1118/ 1.2201149
Klein EE, Hanley J, Bayouth J, et al. Task Group 142 report: quality assurance of medical accelerators. Med Phys. 2009;36(9):4197–212.
I. J. Das, C.-W. Cheng, R. J. Watts, A. Ahnesjo, J. Gibbons, X. A. Li, J. Lowenstein, R. K. Mitra, W. E. Simon, and T. C. Zhu, “Accelerator beam data commissioning equipment and procedures: Report of the TG-106 of the Therapy Physics Committee of the AAPM,” Med. Phys. 35, 4186–4215 (2008)
Sievinen J, Ulmer W, Kaissl W. AAA photon dose calculation model in Eclipse. Palo Alto (CA): Varian Medical Systems; 2005. p. 118.
Musolino SV. Absorbed Dose Determination in External Beam Radiotherapy: An International Code of Practice for Dosimetry Based on Standards of Absorbed Dose to Water; Technical Reports Series No. 398. Health Physics. 2001 Nov 1;81(5):592-3.
Almond PR, Biggs PJ, Coursey BM, Hanson WF, Huq MS, Nath R, et al. AAPM's TG‐51 protocol for clinical reference dosimetry of high‐energy photon and electron beams. Medical physics. 1999 Sep 1;26(9):1847-70.
International Electrotechnical Commission. Medical electrical equipment. Part 2: Particular requirements for the safety of gamma beam therapy equipment. IEC 60601-2-11. Geneva, Switzerland: IEC; 1987.
TRS-483.
Yao W, Farr JB. Determining the optimal dosimetric leaf gap setting for rounded leaf-end multileaf collimator systems by simple test fields. J Appl Clin Med Phys. 2015;16(4):65-77.
Sahani G, Sharma SD, Sharma PD, Deshpande DD, Negi PS, SathianarayananVK , et al. Acceptance criteria for flattening filter-free photon beam from standard medical electron linear accelerator: AERB task group recommendations, Journal of Medical Physics/Association of Medical Physics of India. 2014 Oct;39(4) 206.
Karthick Raj Mani, Md Anisuzzaman Bhuiyan, Md shakilur Rahman, S.M Azharur Islam. Open dosimetriccharacteristcs of True Beam medical linear accelerator with flattening filter (WFF) and flattening filter free (FFF) beam. Polish Journal of Medical Physics and Engineering 2018:24(2):79-89.
TG 119 IMRT Commissioning Tests Instructions for Planning, Measurement, and Analysis Version 10/21/2009. doi: org/10.1118/1.3238104
Pichandi A, Ganeshb KM, Jerina A, Balaji K, Kilaraa G. Analysis of physical parameters and determination of inflection point for flattening filter free beams in medical linear accelerator. Rep Fract Oncol Radiother2014;19:322 31