Evaluation of the dosimetric impact of applying flattening filter-free beams in intensity-modulated radiotherapy for early-stage upper thoracic carcinoma of oesophagus

Journal Article · Mon Jun 15 04:00:00 EDT 2015 · Journal of Medical Radiation Sciences (Print)

DOI:https://doi.org/10.1002/JMRS.93· OSTI ID:22402371

Zhang, Wuzhe; Lin, Zhixiong; Yang, Zhining; Fang, Weisheng; Lai, Peibo; Lu, Jiayang ^[1]

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1. Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong (China)

Flattening filter-free (FFF) radiation beams have recently become clinically available on modern linear accelerators in radiation therapy. This study aimed to evaluate the dosimetric impact of using FFF beams in intensity-modulated radiotherapy (IMRT) for early-stage upper thoracic oesophageal cancer. Eleven patients with primary stage upper thoracic oesophageal cancer were recruited. For each patient, two IMRT plans were computed using conventional beams (Con-P) and FFF beams (FFF-P), respectively. Both plans employed a five-beam arrangement and were prescribed with 64 Gy to (planning target volume) PTV1 and 54 Gy to PTV2 in 32 fractions using 6 MV photons. The dose parameters of the target volumes and organs at risks (OARs), and treatment parameters including the monitor units (MU) and treatment time (TT) for Con-P and FFF-P were recorded and compared. The mean D{sub 5} of PTV1 and PTV2 were higher in FFF-P than Con-P by 0.4 Gy and 0.3 Gy, respectively. For the OARs, all the dose parameters did not show significant difference between the two plans except the mean V{sub 5} and V{sub 10} of the lung in which the FFF-P was lower (46.7% vs. 47.3% and 39.1% vs. 39.6%, respectively). FFF-P required 54% more MU but 18.4% less irradiation time when compared to Con-P. The target volume and OARs dose distributions between the two plans were comparable. However, FFF-P was more effective in sparing the lung from low dose and reduced the mean TT compared with Con-P. Long-term clinical studies are suggested to evaluate the radiobiological effects of FFF beams.

• OSTI ID: 22402371
• Journal Information: Journal of Medical Radiation Sciences (Print), Journal Name: Journal of Medical Radiation Sciences (Print) Journal Issue: 2 Vol. 62; ISSN 2051-3895
• Country of Publication: Australia
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
BEAMS
BIOLOGICAL RADIATION EFFECTS
CARCINOMAS
DOSES
DOSIMETRY
HAZARDS
IRRADIATION
LINEAR ACCELERATORS
LUNGS
PATIENTS
PHOTONS
PLANNING
RADIATION DOSE DISTRIBUTIONS
RADIOTHERAPY