ESTRO 2022 - Abstract Book

S790

Abstract book

ESTRO 2022

Conclusion Based on the measured T1 and T2 of metastases and surrounding liver tissue, optimal MRI sequence settings could be calculated. Personalized 4D-MRI sequence settings improved the contrast between a metastasis and surrounding liver tissue in patients prospectively. References [1] Weykamp et al., doi:10.3389/fonc.2021.610637

PD-0897 In vivo verification by detection of charged fragments in carbon ion therapy treatments at CNAO

M. De Simoni 1 , G. Baroni 2 , G. Battistoni 3 , M.G. Bisogni 4 , P. Cerello 5 , M. Ciocca 6 , M. Donetti 7 , Y. Dong 3 , A. Embriaco 8 , V. Ferrero 5 , E. Fiorina 5 , M. Fischetti 9 , G. Franciosini 10 , G. Giacchi 9 , A. Kraan 4 , C. Luongo 4 , M. Maggi 9 , C. Mancini Terracciano 10 , M. Marafini 11 , E. Malekzadeh 7 , I. Mattei 3 , E. Mazzoni 4 , A. Mirandola 7 , M. Morrocchi 4 , S. Muraro 3 , V. Patera 9 , F. Pennazio 5 , A. Schiavi 9 , E. Solfaroli-Camillucci 10 , G. Sportelli 4 , S. Tampellini 7 , M. Toppi 9 , G. Traini 12 , A. Trigilio 10 , B. Vischioni 7 , V. Vitolo 7 , D. Carlotti 10 , A. De Gregorio 10 , A. Sarti 9 1 Sapienza, University of Rome, Physics , Rome, Italy; 2 Politecnico di Milano, Dipartimento di Elettronica Informazione e Bioingegneria, Milan, Italy; 3 INFN (Istituto Nazionale Fisica Nucleare), Milano, Milan, Italy; 4 INFN (Istituto Nazionale Fisica Nucleare), Pisa, Pisa, Italy; 5 INFN (Istituto Nazionale Fisica Nucleare), Torino, Turin, Italy; 6 CNAO (Centro Nazionale di Adroterapia Oncologica), Pavia, Pavia, Italy; 7 CNAO Centro Nazionale di Adroterapia Oncologica, Pavia, Pavia, Italy; 8 INFN (Istituto Nazionale Fisica Nucleare), Pavia, Pavia, Italy; 9 Sapienza, University of Rome, SBAI (Scienze di Base Applicate all'Ingegneria), Rome, Italy; 10 Sapienza, University of Rome, Physics, Rome, Italy; 11 Museo Storico della Fisica e Centro Studi e Ricerche “E. Fermi”, Roma, Rome, Italy; 12 INFN (Istituto Nazionale Fisica Nucleare), Roma1, Rome, Italy Purpose or Objective The implementation of safety margins while planning Particle Therapy treatments to account for possible morphological variations, prevents the full exploitation of therapy intrinsic precision. The development of an on-line verification system is hence considered a crucial step forward in improving the therapy clinical outcome, allowing to experimentally check the planned and delivered dose consistency and to re-schedule or re-plan the treatments if needed. The Dose Profiler (DP) is a device designed and built to operate as an on-line verification system of the 12C ion treatments, exploiting the secondary charged fragments escaping from the patient body. The capability of spotting morphological variations of the DP has been investigated for pathologies of the neck-head district in the context of a clinical trial carried out at CNAO ( Centro Nazionale di Adroterapia Oncologica , Pavia, Italy) from the INSIDE collaboration. The measured fragment 3D emission map has been compared among the different monitored fractions computing the gamma-index to spot possible inter-fractional changes. Materials and Methods The DP exploits 8 planes of plastic scintillating fibers read-out by Silicon PhotoMultipliers (SiPM) to detect and track the incoming fragments, reconstructing their production point coordinates. After each monitored fraction (for a total of 5 treatment sessions per patient), the 3D image of the fragments’ emission positions is reconstructed back-projecting the detected tracks towards the patient and then compared against the one obtained in the first fraction. Differences in the fragment emission maps correlated to morphological variations have been already observed comparing the 1D projections of the measured maps along the beam direction. A 3D comparison strategy based on the gamma-index calculation has been exploited to better localize the spotted variations in the patient ad improve the technique sensitivity.