Page 34 - Fisica In Medicina n° 1/2017

^Äëíê~Åí=cáëáÅá= =Evaluation of the accuracy of a non-invasive frame designed for fractionated intracranical radiotherapy and stereotactic radiosurgery with Helical TomotherapyM. IACCO 1,2, C. ZUCCHETTI1, C. FULCHERI1, M. LUPATTELLI3, A. DIPILATO1,2, C. ARISTEI2,3, R.TARDUCCI11Santa Maria della Misericordia Hospital, Medical Physics Department, Perugia, Italy2University of Perugia, Surgery and Biomedicine Department, Perugia, Italy3Santa Maria della Misericordia Hospital, Radiation Oncology Department, Perugia, ItalyIntroductionThe study focused on the evaluation of the accuracy of intracranial stereotactic radiosurgery (SRS) and radiotherapy (SRT), delivered with helical Tomotherapy (HT), by means of mask-based fixation systems.Materials and MethodsFirstly, an anthropomorphic phantom was scanned to evaluate the delivery accuracy of the Tomotherapy image guided positioning tool. The megavoltage computed tomography (MVCT), acquired with finest slice thickness (1mm), was automatically registered with the treatment planning CT via the automatic registration algorithm using the “bone and tissue” technique with superfine resolution. After the suggested application of the shifts a second MVCT was acquired and registered with the same procedure. Translational shifts in lateral (IEC-X), longitudinal (IEC-Y) and vertical (IEC-Z) directions and rotations (pitch, roll, yaw), which corresponded to the setup error, were recorded. The same procedure was applied to patients underwent intracranial ipo-fractionated treatments, for a total of 25 MVCT analyzed. The second MVCT scans, performed at the end of the25