Page 66 - Fisica In Medicina n° 1/2017

^Äëíê~Åí=cáëáÅá= =Use of Delta4+ system for verification of SBRT plansA. DANIELE1, R. DI BENEDETTO1, N. FRANZA3, C. GUIDA, C2. IERVOLINO11 Medical Physics of Radiation Oncology AORN “S. G. Moscati” Avellino (Italy) 2Head of Department of Radiation Oncology AORN “S. G. Moscati” Avellino (Italy)3 Holder of Dosimetrica, ScandidosIntroductionIn the usual practice, the 3DRT verification is performed by planar dose verification by 2D array or by inserting multiple films in a slab phantom. Only recently, it makes use of volumetric chek by rotational phantom.In this work 12 SBRT plans, about cerebral and pulmonary treatment, were delivered and verificated by new Delta4 Plus phantom.Method and MaterialsThe plans were delivered with Elekta Versa HD with 6MV FF beams and FFF modality whit mMLC of 0,5cm; the TPS used Pinnacle 9.10 version and phantom used for test was Delta4 Plus with plug in for farmer chamber. Initially tests on Delta4 were carried to assess performance of the phantom about the response on variation of dose rate from minimum dose rate of Linac delivered up to highest; in the same way, it was carried tests for verify the linearity with monitor units variation, starting from the minimum acceptable from linac interface. All performances have been tested considering couch rotational response during the irradiation.Verified the accuracy of Delta4, n.12 plans SBRT were studied. This study was performed sending the original RT plan to Linac and the dose calculated on digital phantom with 1.15 r.e.d. set into TPS. After, was sent all to delta4 software. Gamma functions local and global, DTA, deviation in dose were evaluated for the delivered plans. Also errors on shift of phantom inferior to 1mm were taken into consideration to simulate possible shift in patient treatments and their influence on gamma, dose deviation and DTA.57