Radiological Physics and Technology

, Volume 11, Issue 4, pp 423–433 | Cite as

Evaluation of beam matching accuracy among six linacs from the same vendor

  • Chockkalingam KrishnappanEmail author
  • Chandrasekaran Anu Radha
  • Karunakaran Balaji
  • Prasanna Kumar Mani
  • Vendhan Subramani
  • Velmurugan Thanigaimalai
  • Madhan Kumar Gunasekaran
  • Velayudham Ramasubramanian


The purpose of this study was to evaluate the dosimetric variation among six non-beam-matched Varian linacs using different techniques for the same plans. Six non-beam-matched Varian machines, comprising two Clinac iX, two 600 C/D (Unique), and two True Beam Tx photon 6 MV X-ray devices were acquired. Sixty patients with of head and neck (H&N; 30) and pelvic (30) treatment sites were chosen. For all 60 patients, three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiotherapy (IMRT), and volumetric-modulated radiotherapy (VMAT) plans were generated for the Clinac iX-1 device; all plans were migrated to the remaining machines, using the eclipse treatment planning system without any modification. The dosimetric variation among the six machines for each target volume and organ at risk was recorded and analyzed. In H&N cases, the maximum variation among the six machines with 3DCRT, IMRT, and VMAT was 2.57%, 2.6%, and 2.6%, respectively. In pelvic cases, the maximum variation among the six machines with 3DCRT, IMRT, and VMAT was 2.2%, 1.95%, and 2.05%, respectively. Our overall results show that dosimetric variation, while interchanging the plans among the six machines at phantom and patient levels, remains within the limits of clinical acceptability. The noted variation was not correlated with any of these treatment techniques: 3DCRT, IMRT, or VMAT.


Non-beam-matched linacs Re-planning Dosimetric evaluation TPS commissioning Single-beam data 


Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Statement of human rights

This study has been approved by the appropriate Institutional Review Board (IRB) and has been performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Ethics approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the Institutional Review Board (IRB) and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Research involving animals

This study did not use animals for any experiments.


For this type of retrospective study, formal consent is not required in our Institution.


  1. 1.
    Nath R, Biggs PJ, Bova FJ, Ling CC, Purdy JA, Geijn JVD, Weinhous MS. AAPM code of practice for radiotherapy accelerators: report of AAPM radiation therapy task group no. 45. Med Phys. 1994;21:1094–118.Google Scholar
  2. 2.
    Sjöström D, Bjelkengren U, Ottosson W, Behrens C. A beam-matching concept for medical linear accelerators. Acta Oncol. 2009;48:192–200.CrossRefGoogle Scholar
  3. 3.
    Beyer GP. Commissioning measurements for photon beam data on three TrueBeam linear accelerators and comparison with Trilogy and Clinac 2100 linear accelerators. J Appl Clin Med Phys. 2013;14:273–88.CrossRefGoogle Scholar
  4. 4.
    Bhangle JR, Sathiya Narayanan VK, Kumar NK, Vaitheeswaran R. Dosimetric analysis of beam-matching procedure of two similar linear accelerators. J Med Phys. 2011;36:176–80.CrossRefGoogle Scholar
  5. 5.
    Watts RJ. Comparative measurements on a series of accelerators by the same vendor. Med Phys. 1999;26:2581–5.CrossRefGoogle Scholar
  6. 6.
    Cho SH, Vassiliev ON, Lee S, Liu HH, Ibbott GS, Mohan R. Reference photon beam dosimetry data and reference phase space for the 6 MV photon beam from Varian Clinac 2100 series linear accelerators. Med Phys. 2005;32:137–48.CrossRefGoogle Scholar
  7. 7.
    Hrbacek J, Depuydt T, Nulens A, Swinnen A, Heuvel FD. Quantitative evaluation of a beam-matching procedure using one-dimensional gamma analysis. Med Phys. 2007;34:2917–27.CrossRefGoogle Scholar
  8. 8.
    Lye JE, Butler DJ, Ramanathan G, Franich RD. Spectral differences in 6 MV beams with matched PDDs and the effect on chamber response. Phys Med Biol. 2012;57:7599.CrossRefGoogle Scholar
  9. 9.
    William D, Cody C, Andrew A, Vijayananda K, Gavin CS. Dosimetric characterization of an accessory mounted mini-beam collimator across clinically beam matched medical linear accelerators. Biomed Phys Eng Express. 2017;3:015014.CrossRefGoogle Scholar
  10. 10.
    Sridhar Y, Swetha O, Vivian R, Olga LG, Daniel AL, Dharanipathy R, Sasa M, Murty SG. Independent verification of transferred delivery sinogram between two dosimetrically matched helical tomotherapy machines: a protocol for patient-specific quality assurance. Phys Med Biol. 2012;57:5617.CrossRefGoogle Scholar
  11. 11.
    Krishnappan C, Radha CA, Subramani V, Gunasekaran MK. Is the dose distribution distorted in IMRT and RapidArc treatment when patient plans are swapped across beam-matched machines? J Appl Clin Med Phys. 2016;17:111–23.CrossRefGoogle Scholar
  12. 12.
    Ashokkumar S, Ganesh KM, Ramalingam K, Karthikeyan K, Jagadheeskumar. Dosimetric validation of volumetric modulated arc therapy with three 6MV beam-matched linear acelerators. Asian Pac J Cancer Prev. 2017;18:3439–44.PubMedPubMedCentralGoogle Scholar
  13. 13.
    Das IJ, Cheng CW, Watts RJ, Ahnesjö A, Gibbons J, Allen Li X, Lowenstein J, Mitra RK, Simon WE, Zhu TC. Accelerator beam data commissioning equipment and procedures. Med Phys. 2008;35:4186–215.CrossRefGoogle Scholar
  14. 14.
    Ezzell GA, Burmeister JW, Dogan N, LoSasso TJ, Mechalakos JG, Mihailidis D, Molineu A, Palta JR, Ramsey CR, Salter BJ, Shi J, Xia P, Yue NJ, Xiao Y. IMRT commissioning: multiple institution planning and dosimetry comparisons. Med Phys. 2009;36:5359–73.CrossRefGoogle Scholar
  15. 15.
    Fraass B, Doppke K, Hunt M, Kutcher G, Starkschall G, Stern R, Dyke RV. American Association of Physicists in medicine radiation therapy committee task group 53: quality assurance for clinical treatment planning. Med Phys. 1998;25:1773–829.CrossRefGoogle Scholar
  16. 16.
    Nithya L, Raj NA, Rathinamuthu S, Pandey MB. Analyzing the performance of the planning system by use of AAPM TG 119 test cases. Radiol Phys Technol. 2016;9:22–9.CrossRefGoogle Scholar
  17. 17.
    ICRU. International Commission on Radiation Units and Measurements. Prescribing, recording and reporting photon-beam intensity modulated radiation therapy (IMRT) ICRU Report 83. J ICRU. 2010;10:1.Google Scholar
  18. 18.
    Wambersie A. What accuracy is required and can be achieved in radiation therapy (review of radiobiological and clinical data). Radiochim Acta. 2001;89:255–64.Google Scholar
  19. 19.
    Oliver M, Gagne I, Bush K, Zavgorodni S, Ansbacher W, Beckham W. Clinical significance of multi-leaf collimator positional errors for volumetric modulated arc therapy. Radiother Oncol. 2010;97:554–60.CrossRefGoogle Scholar

Copyright information

© Japanese Society of Radiological Technology and Japan Society of Medical Physics 2018

Authors and Affiliations

  • Chockkalingam Krishnappan
    • 1
    • 2
    Email author
  • Chandrasekaran Anu Radha
    • 2
  • Karunakaran Balaji
    • 2
    • 3
    • 4
  • Prasanna Kumar Mani
    • 2
    • 5
  • Vendhan Subramani
    • 6
  • Velmurugan Thanigaimalai
    • 7
  • Madhan Kumar Gunasekaran
    • 1
  • Velayudham Ramasubramanian
    • 2
  1. 1.Department of Medical PhysicsApollo CBCC HospitalsGandhinagarIndia
  2. 2.School of Advanced SciencesVellore Institute of TechnologyVelloreIndia
  3. 3.Department of Radiation OncologyGlengales Global HospitalsChennaiIndia
  4. 4.Department of Medical PhysicsSanjeevani CBCC Cancer HospitalRaipurIndia
  5. 5.Department of Radiation OncologyApollo HospitalsBengaluruIndia
  6. 6.Department of Medical PhysicsCHL CBCC Cancer CentreIndoreIndia
  7. 7.Department of Radiation OncologyGVN HospitalsTiruchirappalliIndia

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