ESTRO 2022

Session Item

Monday

May 09

14:15 - 15:15

Poster Station 1

21: Implementation of new technology & techniques

Chair: Sebastian Klüter, Germany

Session Code: 3410

Session Type: Poster Discussion

Track: Physics

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

vincenzo patera, Italy

Presentation Number: PD-0897

Abstract

Abstract Title:

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

Authors:

Micol De Simoni¹, Guido Baroni², Giuseppe Battistoni³, Maria Giuseppina Bisogni⁴, Piergiorgio Cerello⁵, Mario Ciocca⁶, Marco Donetti⁷, Yunsheng Dong³, Alessia Embriaco⁸, Veronica Ferrero⁵, Elisa Fiorina⁵, Marta Fischetti⁹, Gaia Franciosini¹⁰, Gabriele Giacchi⁹, Aafke Kraan⁴, Carmela Luongo⁴, Marco Maggi⁹, Carlo Mancini Terracciano¹⁰, Michela Marafini¹¹, Etesam Malekzadeh⁷, Ilaria Mattei³, Enrico Mazzoni⁴, Alfredo Mirandola⁷, Matteo Morrocchi⁴, Silvia Muraro³, Vincenzo Patera⁹, Francesco Pennazio⁵, Angelo Schiavi⁹, Elena Solfaroli-Camillucci¹⁰, Giancarlo Sportelli⁴, Sara Tampellini⁷, Marco Toppi⁹, Giacomo Traini¹², Antonio Trigilio¹⁰, Barbara Vischioni⁷, Viviana Vitolo⁷, Daniele Carlotti¹⁰, Angelica De Gregorio¹⁰, Alessio Sarti⁹

¹Sapienza, University of Rome, Physics , Rome, Italy; ²Politecnico di Milano, Dipartimento di Elettronica Informazione e Bioingegneria, Milan, Italy; ³INFN (Istituto Nazionale Fisica Nucleare), Milano, Milan, Italy; ⁴INFN (Istituto Nazionale Fisica Nucleare), Pisa, Pisa, Italy; ⁵INFN (Istituto Nazionale Fisica Nucleare), Torino, Turin, Italy; ⁶CNAO (Centro Nazionale di Adroterapia Oncologica), Pavia, Pavia, Italy; ⁷CNAO Centro Nazionale di Adroterapia Oncologica, Pavia, Pavia, Italy; ⁸INFN (Istituto Nazionale Fisica Nucleare), Pavia, Pavia, Italy; ⁹Sapienza, University of Rome, SBAI (Scienze di Base Applicate all'Ingegneria), Rome, Italy; ¹⁰Sapienza, University of Rome, Physics, Rome, Italy; ¹¹Museo Storico della Fisica e Centro Studi e Ricerche “E. Fermi”, Roma, Rome, Italy; ¹²INFN (Istituto Nazionale Fisica Nucleare), Roma1, Rome, Italy

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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.

Material 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.

Results

The 3D gamma-index maps have been calculated for 10 patients enrolled in the clinical trial. Morphological variations that occurred in three patients have been identified.

In the figure, the gamma-index map is shown in the case of a patient affected by ACC, superimposed to the CT scan image performed at the planning stage. The clear gamma-index hot spot is correlated to the emptying of the frontal sinuses that occurred during the treatment delivery.

Conclusion

The results of the analysis performed on patients enrolled in the trial clearly indicate that early detection of morphological changes occurring in the tissues crossed by the beam in its entrance path towards the target volume is possible using the DP as monitoring device. In the second part of 2021 other 10 patients will be recruited to study and validate the technique on different pathologies, finalizing the systematic uncertainty studies and technique sensitivity evaluation.