Flattening Filter-Free Beams in Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Sinonasal Cancer

Jia-Yang Lu; Jing Zheng; Wu-Zhe Zhang; Bao-Tian Huang

doi:10.1371/journal.pone.0146604

Flattening Filter-Free Beams in Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy for Sinonasal Cancer

PLoS One. 2016 Jan 6;11(1):e0146604. doi: 10.1371/journal.pone.0146604. eCollection 2016.

Authors

Jia-Yang Lu¹, Jing Zheng², Wu-Zhe Zhang¹, Bao-Tian Huang¹

Affiliations

¹ Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong, China.
² Department of Laboratory, Shantou Central Hospital, Affiliated Shantou Hospital of Sun Yat-sen University, Shantou, Guangdong, China.

Abstract

Purpose: To evaluate the dosimetric impacts of flattening filter-free (FFF) beams in intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) for sinonasal cancer.

Methods: For fourteen cases, IMRT and VMAT planning was performed using 6-MV photon beams with both conventional flattened and FFF modes. The four types of plans were compared in terms of target dose homogeneity and conformity, organ-at-risk (OAR) sparing, number of monitor units (MUs) per fraction, treatment time and pure beam-on time.

Results: FFF beams led to comparable target dose homogeneity, conformity, increased number of MUs and lower doses to the spinal cord, brainstem and normal tissue, compared with flattened beams in both IMRT and VMAT. FFF beams in IMRT resulted in improvements by up to 5.4% for sparing of the contralateral optic structures, with shortened treatment time by 9.5%. However, FFF beams provided comparable overall OAR sparing and treatment time in VMAT. With FFF mode, VMAT yielded inferior homogeneity and superior conformity compared with IMRT, with comparable overall OAR sparing and significantly shorter treatment time.

Conclusions: Using FFF beams in IMRT and VMAT is feasible for the treatment of sinonasal cancer. Our results suggest that the delivery mode of FFF beams may play an encouraging role with better sparing of contralateral optic OARs and treatment efficiency in IMRT, but yield comparable results in VMAT.

Publication types

Comparative Study
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Aged
Female
Humans
Male
Middle Aged
Nose Neoplasms / radiotherapy*
Organs at Risk
Radiometry
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted* / instrumentation
Radiotherapy, Intensity-Modulated* / instrumentation

Grants and funding

This work was supported by Shantou Medical Science and Technology Project [Grant No. (2015)123] and Medical Scientific Research Foundation of Guangdong Province (Grant No. A2015534). No additional external funding was received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.