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SU‐GG‐T‐446: Dosimetric Characteristics of High Definition Multi‐Leaf Collimator

Publication ,  Conference
Wang, Z; Chang, Z; wu, Q; Zhou, S; Huntzinger, C; Yin, F
Published in: Medical Physics
January 1, 2008

Purpose: A new type of high‐definition multi‐leaf collimator (HD 120 MLC, Varian Medical Systems) is being introduced into clinical practice to improve the conformality of stereotactic radiation therapy and radiosurgery. Its leaf width at isocenter is 2.5 mm. The interface and casing are the same as Millennium 120 MLC so it can be easily fit inside the gantry for better clearance and efficiency. This study investigated the dosimetric characteristics of this new micro MLC. Method and Materials: The HD 120 MLC was installed in a Novalis TX dedicated image‐guided SRS/SBRT machine. Beam penumbra (defined between 20–80%) was measured with a scanning radiosurgery diode for various field sizes, depth, and beam energies. Dynamic dosimetric gap and leaf transmission were measured with both low (6 MV and 6 MV SRS) and high energy (15 MV) photon beams. The conformity and step effect were studied with a series of circular beams with various radius. Results: The penumbra of HD 120 MLC was measured to be 0.25 cm for 6 MV at 1.5 cm depth with 2 cm × 2 cm field size. It increases to 0.49 cm for 30 cm × 30 cm field size. For 15 MV at 3 cm depth, the penumbra increases from 0.36 cm at 2 cm × 2 cm to 0.60 at 30 cm × 30 cm. For other field sizes and depth, the penumbra values are listed in Table I. The dynamic dosimetric gap was 0.86 cm for 6 MV and 0.98 mm for 15 MV. The leaf transmission factors were 1.17% for 6 MV and 1.33% for 15 MV. Conclusion: HD 120 MLC provides finer beam penumbra, smaller dynamic dose gap, and lower leaf transmission compared to conventional Millennium MLC, and can thus potentially improve the conformality of SRS/SBRT treatments. © 2008, American Association of Physicists in Medicine. All rights reserved.

Duke Scholars

Published In

Medical Physics

DOI

ISSN

0094-2405

Publication Date

January 1, 2008

Volume

35

Issue

6

Start / End Page

2827

Related Subject Headings

  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering
  • 0299 Other Physical Sciences
 

Citation

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Wang, Z., Chang, Z., wu, Q., Zhou, S., Huntzinger, C., & Yin, F. (2008). SU‐GG‐T‐446: Dosimetric Characteristics of High Definition Multi‐Leaf Collimator. In Medical Physics (Vol. 35, p. 2827). https://doi.org/10.1118/1.2962194
Wang, Z., Z. Chang, Q. wu, S. Zhou, C. Huntzinger, and F. Yin. “SU‐GG‐T‐446: Dosimetric Characteristics of High Definition Multi‐Leaf Collimator.” In Medical Physics, 35:2827, 2008. https://doi.org/10.1118/1.2962194.
Wang Z, Chang Z, wu Q, Zhou S, Huntzinger C, Yin F. SU‐GG‐T‐446: Dosimetric Characteristics of High Definition Multi‐Leaf Collimator. In: Medical Physics. 2008. p. 2827.
Wang, Z., et al. “SU‐GG‐T‐446: Dosimetric Characteristics of High Definition Multi‐Leaf Collimator.” Medical Physics, vol. 35, no. 6, 2008, p. 2827. Scopus, doi:10.1118/1.2962194.
Wang Z, Chang Z, wu Q, Zhou S, Huntzinger C, Yin F. SU‐GG‐T‐446: Dosimetric Characteristics of High Definition Multi‐Leaf Collimator. Medical Physics. 2008. p. 2827.

Published In

Medical Physics

DOI

ISSN

0094-2405

Publication Date

January 1, 2008

Volume

35

Issue

6

Start / End Page

2827

Related Subject Headings

  • Nuclear Medicine & Medical Imaging
  • 5105 Medical and biological physics
  • 4003 Biomedical engineering
  • 1112 Oncology and Carcinogenesis
  • 0903 Biomedical Engineering
  • 0299 Other Physical Sciences