• Patricia Doornaert, Wilko F A R Verbakel, Michael Bieker, Ben J Slotman, and Suresh Senan.
• Department of Radiation Oncology, VU University Medical Center, Amsterdam, The Netherlands. p.doornaert@vumc.nl
• Int. J. Radiat. Oncol. Biol. Phys. 2011 Feb 1; 79 (2): 429-35.

PurposeVolumetric modulated arc therapy (RapidArc, Varian Medical Systems) permits the delivery of highly conformal dose distributions. We studied planning and delivery in patients who underwent RapidArc for locally advanced head-and-neck cancer (HNC).Methods And MaterialsA total of 35 consecutive patients who completed RapidArc with concurrent chemotherapy for Stages III-IV tumors of the oro- and hypopharynx/larynx in our center were identified. All underwent bilateral neck irradiation and 21 patients had at least N2 disease. A simultaneous integrated boost (SIB) delivered 70 Gy (in 2 Gy/fraction) to the planning target volume (PTV)(boost) and elective nodal regions (PTV(elect)) received 57.75 Gy. A standard planning constraint set was used and constraints for parotid glands were individually adapted. Treatments were delivered using two arcs after all plans were verified in a solid water phantom using GafChromic External Beam Therapy films.ResultsRapidArc planning generally took 1.5-2 h, which was faster than with our previous seven-field intensity-modulated radiotherapy sliding window technique. Film dosimetry revealed that 0.6% of films exceeded a combination of dose differences ≥3% or distance to agreement ≥2 mm. More than 99% of both PTVs received ≥95% of the prescription dose. Average plan conformity index was 1.13 and mean dose to ipsilateral and contralateral parotid glands were 31.4 Gy and 26.1 Gy, respectively. The mean beam-on time was <3 min and mean number of monitor units was 426.ConclusionsRapidArc achieved excellent target coverage and normal tissue sparing, with delivery completed in less than 3 min. RA is currently our standard intensity-modulated radiotherapy approach for advanced HNC.Copyright © 2011 Elsevier Inc. All rights reserved.

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