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SU-E-T-559: Evaluation of Flatening Filter Free (FFF) Beams in Radiotherapy of Head and Neck Cancer.

Publication ,  Journal Article
Wu, Q; Yoo, S; Das, S; Yin, F
Published in: Med Phys
June 2012

PURPOSE: To investigate th applicability of the flattening filter free (FFF) to fractionated radiotherapy of head and neck cancer. METHODS: Twelve patients previously treated with IMRT were selected. A SIB protocol was chosen so that 66/54 Gy were prescribed to the gross tumors/elective nodal volumes in 30 fractions. Photon beams of 6X(6X-FFF) were used for both IMRT (@ 9 gantry angles) and VMAT (single and dual full arcs). Consistent optimization and acceptance criteria were used for all plans, with prescription dose to cover 90% of PTV66 and hot spots limited to 110% and within PTV66. Both plan quality and deliver-ability were compared. RESULTS: All plans met clinical objectives. The IMRT plan quality is similar or slightly better than VMAT, except that PTV66 conformity index is significantly better in 2-arc VMAT (1.18) than IMRT (1.32). The total MUs for IMRT are 1680/2090 for 6X/6X-FFF, a 24% increase. However, the total beam-on time (BOT) under treatment automation is 430/400 seconds for 6X(@300 MU/min)/6X-FFF (@400 MU/min), a 6% decrease. Increasing dose rate to the maximum (600/1400 for 6X and 6X-FFF) can reduce BOT by up to 50%, but at a cost of increased MU (up to 40%) and degraded plan quality. Significant reduction in MU and BOT are realized in VMAT, with ∼600 MU for both 6X and 6X-FFF and either single or dual-arcs. The BOT for VMAT is governed by the gantry speed and approximately 1 min for single arc and 2 min for dual arcs. CONCLUSIONS: Plan quality is similar between IMRT and 2-arc VMAT for both 6X and 6X-FFF. Total MU for IMRT and delivery time is significantly higher for IMRT than VMAT, but not much different between flat and non-flat beams. For standard fractionated radiotherapy of HN cancer, there is no advantage for the non-flat beam. The recommended choice is 2-arc VMAT.

Duke Scholars

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

June 2012

Volume

39

Issue

6Part19

Start / End Page

3834

Location

United States

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

APA
Chicago
ICMJE
MLA
NLM
Wu, Q., Yoo, S., Das, S., & Yin, F. (2012). SU-E-T-559: Evaluation of Flatening Filter Free (FFF) Beams in Radiotherapy of Head and Neck Cancer. Med Phys, 39(6Part19), 3834. https://doi.org/10.1118/1.4735648
Wu, Q., S. Yoo, S. Das, and F. Yin. “SU-E-T-559: Evaluation of Flatening Filter Free (FFF) Beams in Radiotherapy of Head and Neck Cancer.Med Phys 39, no. 6Part19 (June 2012): 3834. https://doi.org/10.1118/1.4735648.
Wu, Q., et al. “SU-E-T-559: Evaluation of Flatening Filter Free (FFF) Beams in Radiotherapy of Head and Neck Cancer.Med Phys, vol. 39, no. 6Part19, June 2012, p. 3834. Pubmed, doi:10.1118/1.4735648.

Published In

Med Phys

DOI

EISSN

2473-4209

Publication Date

June 2012

Volume

39

Issue

6Part19

Start / End Page

3834

Location

United States

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