ESTRO 2024 - Abstract Book

S3301

Physics - Detectors, dose measurement and phantoms

ESTRO 2024

Conclusion:

SRS Mapcheck and film showed comparable abilities to detect geometrical errors in delivery of trigeminal neuralgia with Cyberknife. Based on SPC analysis, and once a systematic error due to misrepresentation of the array central detector in the planning CT, SRS Mapcheck showed enough reproducibility to established tolerance limits of ±0.75mm.

Gamma index passing rates with SRSMapcheck show a good behavior of the system when measuring absolute dose distributions.

Keywords: Trigeminal neuralgia, Cyberknife, diode array

2053

Digital Poster

An Italian multi-department study for relative dosimetry in tomotherapy

Cinzia Talamonti 1,2 , Chiara Arilli 2 , Elena Gallio 3 , Livia Marrazzo 1,2 , Sara Broggi 4 , Claudio Zucchetti 5 , Serenella Russo 6 , Pietro Mancosu 7 , Francesca Romana Giglioli 3 1 University of Florence, Experimental and Clinical Biomedical Sciences “Mario Serio”, Florence, Italy. 2 A.O.U Careggi, Medical Physics Unit, Florence, Italy. 3 A.O.U. Città della Salute e della Scienza di Torino,, Medical Physics Unit, Torino, Italy. 4 IRCCS San Raffaele Scientific Institute, Medical Physics Unit, Milano, Italy. 5 Azienda Ospedaliera di Perugia, Medical Physics Unit, Perugia, Italy. 6 Azienda USL Toscana Centro Presidio S.Maria Annunziata, Medical Physics Unit, Florence, Italy. 7 IRCCS Humanitas Research Hospital, Department of Radiotherapy and Radiosurgery, Milano, Italy

Purpose/Objective:

In Tomotherapy dose measurements cannot be performed in standard conditions and new references were thus established by AAPM TRS 483. The aim of the work is to develop a consistent dataset to be used as reference for on site measurements validation to encourage data standardization. Five Italian radiotherapy departments were involved in common measurements of output factors of small fields in Tomotherapy units by using new generation solid state detectors, ionization chamber and phantoms. Preliminary results of the measurements performed in five radiotherapy centers are reported.

Material/Methods:

Razor Chamber (RC), Razor Diode (RD)) were tested in measuring output factor. One center measured the output factors (OFs) of 12 small fields shaped by MLC (X=1.25, 2.5, 3.75, 5 cm) and Jaws (Y =1, 2.5, 5 cm) in a water phantom, moreover all centers performed measurements in a solid water phantom. RD measurements in water