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Commissioning and dosimetric characteristics of TrueBeam system: composite data of three TrueBeam machines.

Publication ,  Journal Article
Chang, Z; Wu, Q; Adamson, J; Ren, L; Bowsher, J; Yan, H; Thomas, A; Yin, F-F
Published in: Med Phys
November 2012

PURPOSE: A TrueBeam linear accelerator (TB-LINAC) is designed to deliver traditionally flattened and flattening-filter-free (FFF) beams. Although it has been widely adopted in many clinics for patient treatment, limited information is available related to commissioning of this type of machine. In this work, commissioning data of three units were measured, and multiunit comparison was presented to provide valuable insights and reliable evaluations on the characteristics of the new treatment system. METHODS: The TB-LINAC is equipped with newly designed waveguide, carousel assembly, monitoring control, and integrated imaging systems. Each machine in this study has 4, 6, 8, 10, 15 MV flattened photon beams, and 6 MV and 10 MV FFF photon beams as well as 6, 9, 12, 16, 20, and 22 MeV electron beams. Dosimetric characteristics of the three new TB-LINAC treatment units are systematically measured for commissioning. High-resolution diode detectors and ion chambers were used to measure dosimetric data for a range of field sizes from 10 × 10 to 400 × 400 mm(2). The composite dosimetric data of the three units are presented in this work. The commissioning of intensity modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), image-guided radiation therapy, and gating systems are also illustrated. Critical considerations of P(ion) of FFF photon beams and small field dosimetric measurements were investigated. RESULTS: The authors found all PDDs and profiles matched well among the three machines. Beam data were quantitatively compared and combined through average to yield composite beam data. The discrepancies among the machines were quantified using standard deviation (SD). The mean SD of the PDDs among the three units is 0.12%, and the mean SD of the profiles is 0.40% for 10 MV FFF open fields. The variations of P(ion) of the chamber CC13 is 1.2 ± 0.1% under 6 MV FFF and 2.0 ± 0.5% under 10 MV FFF from dmax to the 18 cm-off-axis point at 35 cm depth under 40 × 40 cm(2). The mean penumbra of crossplane flattened photon beams at collimator angle of 0° is measured from 5.88 ± 0.09 to 5.99 ± 0.13 mm from 4 to 15 MV at 10 cm depth of 100 × 100 mm(2). The mean penumbra of crossplane beams at collimator angle of 0° is measured as 3.70 ± 0.21 and 4.83 ± 0.04 mm for 6 MV FFF and 10 MV FFF, respectively, at 10 cm depth with a field size of 5 × 5 cm(2). The end-to-end test procedures of both IMRT and VMAT were performed for various energy modes. The mean ion chamber measurements of three units showed less than 2% between measurement and calculation; the mean MultiCube ICA measurements demonstrated over 90% pixels passing gamma analysis (3%, 3 mm, 5% threshold). The imaging dosimetric data of KV planar imaging and CBCT demonstrated improved consistency with vendor specifications and dose reduction for certain imaging protocols. The gated output verification showed a discrepancy of 0.05% or less between gating radiation delivery and nongating radiation delivery. CONCLUSIONS: The commissioning data indicated good consistency among the three TB-LINAC units. The commissioning data provided us valuable insights and reliable evaluations on the characteristics of the new treatment system. The systematically measured data might be useful for future reference.

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Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

November 2012

Volume

39

Issue

11

Start / End Page

6981 / 7018

Location

United States

Related Subject Headings

  • Scattering, Radiation
  • Respiration
  • Radiotherapy, Intensity-Modulated
  • Radiometry
  • Particle Accelerators
  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering
 

Citation

APA
Chicago
ICMJE
MLA
NLM
Chang, Z., Wu, Q., Adamson, J., Ren, L., Bowsher, J., Yan, H., … Yin, F.-F. (2012). Commissioning and dosimetric characteristics of TrueBeam system: composite data of three TrueBeam machines. Med Phys, 39(11), 6981–7018. https://doi.org/10.1118/1.4762682
Chang, Zheng, Qiuwen Wu, Justus Adamson, Lei Ren, James Bowsher, Hui Yan, Andrew Thomas, and Fang-Fang Yin. “Commissioning and dosimetric characteristics of TrueBeam system: composite data of three TrueBeam machines.Med Phys 39, no. 11 (November 2012): 6981–7018. https://doi.org/10.1118/1.4762682.
Chang Z, Wu Q, Adamson J, Ren L, Bowsher J, Yan H, et al. Commissioning and dosimetric characteristics of TrueBeam system: composite data of three TrueBeam machines. Med Phys. 2012 Nov;39(11):6981–7018.
Chang, Zheng, et al. “Commissioning and dosimetric characteristics of TrueBeam system: composite data of three TrueBeam machines.Med Phys, vol. 39, no. 11, Nov. 2012, pp. 6981–7018. Pubmed, doi:10.1118/1.4762682.
Chang Z, Wu Q, Adamson J, Ren L, Bowsher J, Yan H, Thomas A, Yin F-F. Commissioning and dosimetric characteristics of TrueBeam system: composite data of three TrueBeam machines. Med Phys. 2012 Nov;39(11):6981–7018.

Published In

Med Phys

DOI

ISSN

0094-2405

Publication Date

November 2012

Volume

39

Issue

11

Start / End Page

6981 / 7018

Location

United States

Related Subject Headings

  • Scattering, Radiation
  • Respiration
  • Radiotherapy, Intensity-Modulated
  • Radiometry
  • Particle Accelerators
  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering