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SU‐E‐T‐215: Comparison of VMAT‐SABR Treatment Plans with Flattened Filter (FF) Beam and Flattening Filter‐Free (FFF) Beam for Localized Prostate Cancer
Author(s) -
Chung J,
Kim J,
Kang S,
Suh T
Publication year - 2015
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.4924576
Subject(s) - sabr volatility model , nuclear medicine , beam (structure) , dosimetry , medicine , physics , mathematics , optics , volatility (finance) , stochastic volatility , econometrics
Purpose: The purpose of this study is to access VMAT‐SABR plan using flattening filter (FF) and flattening filter‐free (FFF) beam, and compare the verification results for all pretreatment plans. Methods: SABR plans for 20 prostate patients were optimized in the Eclipse treatment planning system. A prescription dose was 42.7 Gy/7 fractions. Four SABR plans for each patient were calculated using Acuros XB algorithm with both FF and FFF beams of 6‐ and 10‐MV. The dose‐volume histograms (DVH) and technical parameters were recorded and compared. A pretreatment verification was performed and the gamma analysis was used to quantify the agreement between calculations and measurements. Results: For each patient, the DVHs are closely similar for plans of four different beams. There are small differences showed in dose distributions and corresponding DVHs when comparing the each plan related to the same patient. Sparing on bladder and rectum was slightly better on plans with 10‐MV FF and FFF than with 6‐MV FF and FFF, but this difference was negligible. However, there was no significance in the other OARs. The mean agreement of 3%/3mm criteria was higher than 97% in all plans. The mean MUs and deliver time employed was 1701±101 and 3.02±0.17 min for 6‐MV FF, 1870±116 and 1.69±0.08 min for 6‐MV FFF, 1471±86 and 2.68±0.14 min for 10‐MV FF, and 1619±101 and 0.98±0.04 min for 10‐MV FFF, respectively. Conclusion: Dose distributions on prostate SABR plans using FFF beams were similar to those generated by FF beams. However, the use of FFF beam offers a clear benefit in delivery time when compared to FF beam. Verification of pretreatment also represented the acceptable and comparable results in all plans using FF beam as well as FFF beam. Therefore, this study suggests that the use of FFF beam is feasible and efficient technique for prostate SABR.