Nome Journal: Frontiers in oncology

Data pubblicazione: 26 September 2022

Autori: Martina Moglioni, Aafke Christine Kraan, Guido Baroni, Giuseppe Battistoni, Nicola Belcari, Andrea Berti, Pietro Carra, Piergiorgio Cerello, Mario Ciocca, Angelica De Gregorio, Micol De Simoni, Damiano Del Sarto, Marco Donetti, Yunsheng Dong, Alessia Embriaco, Maria Evelina Fantacci, Veronica Ferrero, Elisa Fiorina, Marta Fischetti, Gaia Franciosini, Giuseppe Giraudo, Francesco Laruina, Davide Maestri, Marco Magi, Giuseppe Magro, Etesam Malekzadeh, Michela Marafini, Ilaria Mattei, Enrico Mazzoni, Paolo Mereu, Alfredo Mirandola, Matteo Morrocchi, Silvia Muraro, Ester Orlandi, Vincenzo Patera, Francesco Pennazio, Marco Pullia, Alessandra Retico, Angelo Rivetti, Manuel Dionisio Da Rocha Rolo, Valeria Rosso, Alessio Sarti, Angelo Schiavi, Adalberto Sciubba, Giancarlo Sportelli, Sara Tampellini, Marco Toppi, Giacomo Traini, Antonio Trigilio, Serena Marta Valle, Francesca Valvo, Barbara Vischioni, Viviana Vitolo, Richard Wheadon and Maria Giuseppina Bisogni

Abstract:

Morphological changes that may arise through a treatment course are probably one of the most significant sources of range uncertainty in proton therapy. Non- invasive in-vivo treatment monitoring is useful to increase treatment quality. The INSIDE in-beam Positron Emission Tomography (PET) scanner performs in-vivo range monitoring in proton and carbon therapy treatments at the National Center of Oncological Hadrontherapy (CNAO). It is currently in a clinical trial (ID: NCT03662373) and has acquired in-beam PET data during the treatment of various patients. In this work we analyze the in-beam PET (IB-PET) data of eight patients treated with proton therapy at CNAO. The goal of the analysis is twofold. First, we assess the level of experimental fluctuations in inter-fractional range differences (sensitivity) of the INSIDE PET system by studying patients without morphological changes. Second, we use the obtained results to see whether we can observe anomalously large range variations in patients where morphological changes have occurred. The sensitivity of the INSIDE IB-PET scanner was quantified as the standard deviation of the range difference distributions observed for six patients that did not show morphological changes. Inter- fractional range variations with respect to a reference distribution were estimated using the Most-Likely-Shift (MLS) method. To establish the efficacy of this method, we made a comparison with the Beam's Eye View (BEV) method. For patients showing no morphological changes in the control CT the average range variation standard deviation was found to be 2.5 mm with the MLS method and 2.3 mm with the BEV method. On the other hand, for patients where some small anatomical changes occurred, we found larger standard deviation values. In these patients we evaluated where anomalous range differences were found and compared them with the CT. We found that the identified regions were mostly in agreement with the morphological changes seen in the CT scan.

DOI: 10.3389/fonc.2022.929949