Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2017 Jul 5;12(1):114.
doi: 10.1186/s13014-017-0850-8.

Simultaneous integrated boost therapy of carcinoma of the hypopharynx/larynx with and without flattening filter - a treatment planning and dosimetry study

Barbara Dobler  1 , Tina Obermeier  2 , Matthias G Hautmann  2 , Amine Khemissi  2 , Oliver Koelbl  2
Affiliations
Comparative Study

Simultaneous integrated boost therapy of carcinoma of the hypopharynx/larynx with and without flattening filter - a treatment planning and dosimetry study

Barbara Dobler et al. Radiat Oncol. .

Abstract

Background: The aim of this study was to investigate if the flattening filter free (FFF) irradiation mode of a linear accelerator (linac) is advantageous as compared to the flat beam (FF) irradiation mode in intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for carcinoma of the hypopharynx / larynx.

Methods: Four treatment plans were created for each of 10 patients for an Elekta Synergy linac with Agility collimating device, a dual arc VMAT and a nine field step and shoot IMRT each with and without flattening filter. Plan quality was compared considering target coverage and dose to the organs at risk. All plans were verified by a 2D-ionization-chamber-array and delivery times were compared. Peripheral point doses were determined as a measure of second cancer risk. The Wilcoxon test was used for statistical analysis with a significance level of 0.05.

Results: Plan quality was similar for all four treatment plans without statistically significant differences of clinical relevance. The clinical goals were met in all plans for the PTV-SIB (V95% > 95%), the spinal cord (D1ccm < 45 Gy) and the brain stem (D1ccm < 48 Gy). For the parotids, the goal of D50% < 30 Gy was met in 70% and 60% of the plans for the left and right parotid respectively, and the V95% of the SIB reached an average of 94%. Delivery times were similar for FF and FFF and significantly decreased by around 70% for VMAT as compared to IMRT. Peripheral doses were significantly reduced by 18% in FFF mode as compared to FF and by 26% for VMAT as compared to IMRT. Lowest peripheral doses were found for VMAT FFF, followed by VMAT FF.

Conclusions: The FFF mode of a linear accelerator is advantageous for the treatment of hypopharynx/larynx carcinoma only with respect to reduction of second cancer induction in peripheral organs for the combination of Elekta Synergy linacs and Oncentra® External Beam v4.5 treatment planning system. This might be of interest in a therapy with curative intent.

Keywords: Flattening filter free; Hypopharynx carcinoma; Larynx carcinoma; Peripheral dose; Radiation induced second cancer; Simultaneous integrated boost.

PubMed Disclaimer

Conflict of interest statement

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors state there are no conflicts of interest.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Comparison of dose distributions. Comparison of dose distributions in one transversal (left) and one sagittal (right) slice for a representative case. The PTV is drawn in red, SIB dark blue, left parotid orange, right parotid olive, spinal cord cobalt blue, brainstem green, and patient outline orange. The light blue isodose line represents 95% of the prescription dose to the PTV, the green isodose the 95% of the prescription dose to the SIB
Fig. 2
Fig. 2
Comparison of dose volume histograms. Comparison of dose volume histograms for the case of Fig. 1. Top IMRT, bottom VMAT. Solid lines represent FFF, dotted lines FF. The PTV is drawn in red, SIB dark blue, left parotid orange, right parotid olive, spinal cord cobalt blue, brainstem green, and healthy tissue (patient outline excluding targets) light blue
See this image and copyright information in PMC

References

    1. Bonner JA, Harari PM, Giralt J, Azarnia N, Shin DM, Cohen RB, et al. Radiotherapy plus cetuximab for squamous-cell carcinoma of the head and neck. N Engl J Med. 2006;354(6):567–578. doi: 10.1056/NEJMoa053422. - DOI - PubMed
    1. Cooper JS, Zhang Q, Pajak TF, Forastiere AA, Jacobs J, Saxman SB, et al. Long-term follow-up of the RTOG 9501/intergroup phase III trial: postoperative concurrent radiation therapy and chemotherapy in high-risk squamous cell carcinoma of the head and neck. Int J Radiat Oncol Biol Phys. 2012;84(5):1198–1205. doi: 10.1016/j.ijrobp.2012.05.008. - DOI - PMC - PubMed
    1. Thariat J, Bolle S, Demizu Y, Marcy PY, Hu Y, Santini J, et al. New techniques in radiation therapy for head and neck cancer: IMRT, CyberKnife, protons, and carbon ions. Improved effectiveness and safety? Impact on survival? Anti-Cancer Drugs. 2011;22(7):596–606. doi: 10.1097/CAD.0b013e328340fd2b. - DOI - PubMed
    1. Miah AB, Bhide SA, Guerrero-Urbano MT, Clark C, Bidmead AM, St Rose S, et al. Dose-escalated intensity-modulated radiotherapy is feasible and may improve locoregional control and laryngeal preservation in laryngo-hypopharyngeal cancers. Int J Radiat Oncol Biol Phys. 2012;82(2):539–547. doi: 10.1016/j.ijrobp.2010.09.055. - DOI - PubMed
    1. Fogliata A, Bolsi A, Cozzi L, Bernier J. Comparative dosimetric evaluation of the simultaneous integrated boost with photon intensity modulation in head and neck cancer patients. Radiother Oncol. 2003;69(3):267–275. doi: 10.1016/j.radonc.2003.10.003. - DOI - PubMed

Publication types

MeSH terms

LinkOut - more resources