Page 62 - Fisica In Medicina n° 1/2017

^Äëíê~Åí=cáëáÅá= =PRO---ART Project: geometric results and dosimetric impact of rotations correction in Stereotactic Radiation therapy. Final Results of a prospective studyS.CHIESA1,A.R.ALITTO1,S.MENNA2,L.AZARIO2,G.C.MATTIUCCI1,M.A.G AMBACORTA1,F.CELLINI1,G.MANTINI1,V.VALENTINI1,M.BALDUCCI11Radiotherapy Unit, Gemelli-ART, Università Cattolica S.Cuore, Roma2Physics Institute & Operative Unit of MedicalPhysics, UniversitàCattolica S.Cuore,RomaIntroductionExtreme setup accuracy, organ motion control, margin reduction constitute a radiation therapy challenge, especially in Stereotactic body radiation therapy (SBRT). PRO-ART Project was designed to evaluate the 6 - Degree of Freedom (6DoF) utility in this setting.Materials and MethodsPatients with lung, brain or abdominal lesions were considered and immobilized with Uni-frame or trUpoint Arch for brain, Breast Board or Body Pro-Lok for chest and abdomen (CIVCO Support system) lesions. Dose Calculations for VMAT Optimization were performed using EclipseTM Treatment Planning Systems (Varian Medical System®,Palo Alto,CA). Before dose delivery, a daily KV-Cone Beam Computed Tomography (CBCT) was performed and translational and rotational shifts were identified and applied on the Protura TM Robotic couch. Using MIM 5.5.2 software, the simulation CT was rigidly registered with CBCT for each fraction. Then, translational shifts were applied, obtaining a translated CT(tCT), i.e. CT with only translational errors correction. Then, rotational errors were corrected too, obtaining roto-translated CT(rtCT). Initial treatment plan was copied to translated CT(tTP) and roto-translated CT(rtTP). Mean Translational and rotational shifts were calculated and dosimetric parameters were compared.53