Comparison of conformal arc and VMAT techniques according to RTOG 0915 protocol for lung SBRT plans

Recently, with the development of technology, Cranial SRS treatments which have been used early 1970s' also started treat such as lung, liver and prostate and commonly named Sterotactic Body Radiation Theraphy (SBRT). In this study, by using the algorithm of Acuras XB, which makes better dose calculations, treatment planning for 20 non-small lung cancer patients were done according to the physical accept criterias of the latest lung SBRT protocol RTOG 0915. VMAT, conformal arc techniques with 6 MV FF and FFF energy modalities were used for treatment planning. One of the inspected criteria CI index has statistical significance on VMAT technique to conformal arc technique (p = 0,001). Also FFF energy modality have better CI than FF and statistical significance for VMAT and conformal arc techniques respectively ( p = 0,001, p = 0,001) values have been founded. Middle dose areas is studied by looking at ratio of %50 of the prescribed dose to PTV volume volume which has statistical significance on VMAT technique to conformal arc technique (p = 0,001). Comparision of middle dose area values FFF and FF energy modalities in VMAT and conformal arc techniques have statistical significances for FFF energy modality respectively ( p = 0,001, p = 0,001) values have been founded. Another criteria is % dose value of 2cm away from PTV has statistical significance on VMAT technique to conformal arc technique (p = 0,004). Despite statistical significance between FFF and FF energy modes in VMAT technique, ( p = 0,01 ) there is no statistical significance between FFF and FF energy modes in conformal arc technique ( p = 0,064). Another inspected criteria is V20Gy values have statistical significance on VMAT technique to conformal arc technique (p = 0,001). Also FFF energy modality have better than V20Gy values than FF and statistical significance of VMAT and conformal arc techniques' FFF energy modalities are ( p = 0,01, p = 0,01). Obtained MU values of VMAT technique are very high then conformal arc technique and has statistical significance (p = 0,001). There is no statistical significance between FFF and FF energy modalities (p = 0,089). Result of the research points that VMAT technique with 6 MV FFF energy modality has statistical significance over all RTOG 0915 criterias. VMAT technique and FFF energy modality should use for better and high quality SBRT treatments.