Page 68 - Fisica In Medicina n° 1/2017

^Äëíê~Åí=jÉÇáÅá= =Are hippocampi considered organs at risks during stereotactic radiotherapy for brain metastases?A. FIORENTINO1, G. SICIGNANO1, U. TEBANO1,2, N. GIAJ-LEVRA1, S. FERSINO1, R. MAZZOLA1, F. RICCHETTI1, S. NACCARATO1, R. RUGGIERI1, F. ALONGI11Radiation Oncology Division, Sacro Cuore Don Calabria Hospital, Cancer Care Center, Negrar-Verona, Italy2Radiation Oncology Division, University of Padua, Padua, ItalyIntroductionHippocampal-dependent neurocognitive functions, including learning, memory and spatial informations processing, could be affected by brain radiotherapy. Aim of the present study is to evaluate the dose to omolateral and contralateral hippocampus (O-H, C-H, respectively) during Stereotactic Radiotherapy (SRT) or Radiosurgery (SRS) for brain metastases (BM).Materials & MethodsPatients eligible for SRS/SRT treatment had a number of BM <5, with a size ≤30mm, Karnosky Performance Status (KPS) ≥ 80 and a life expectancy over 3 months. Gross Tumour Volume (GTV) was delineated by the fusion between Magnetic Resonance Imaging and Computed Tomography. A Planning Target Volume (PTV) was obtained from GTV by adding a 2mm isotropic margin. The total dose ranged between 18-27 Gy in 1-3 fractions. For each BM, a Volumetric modulated arc therapy plan was generated with one or two arcs and hippocampus sparing was not considered during optimizations phase. For the dosimetric evaluation of O-H and C-H, the Dmedian, Dmean, D0.1cc and the V1Gy, V2Gy, V5Gy and V10Gy were analyzed.ResultsFrom April 2014 to December 2015, 81 BM in 41 patients were treated with SRS/SRT and selected for the present analysis. The average value of PTV dimension and hippocampus volumes were (5.8 + 9.5) cc and (1.1 + 0.3) cc, respectively.59