Boron Neutron Capture Therapy (BNCT) is an advanced form of radiotherapy that relies on the 10B(n,α)7Li nuclear reaction to selectively target and destroy tumor cells. One of the main aspect, which turned out to be critical, is dose monitoring during BNCT treatments. In this work, Monte Carlo simulations using the FLUKA code were carried out to replicate the experimental session conducted at the NUANS facility in Nagoya, with the aim of testing a prototype SPECT detector for the online dose monitoring. This device is designed with the goal to measure the dose during treatment by monitoring the 478 keV gamma photons emitted by the 10B(n,α)7Li reaction. The main goal of this work is to optimize the overall performance of the system, through a detailed understanding of the background signal observed near 478 keV in the absence of boron in the target. The study identifies the origin of the background signal in the neutron interactions with boron, contained in the material of the detector’s electronic boards, and with the scintillator crystal. Two mitigation strategies were proposed and tested via simulation: improved shielding with and substitution of the electronics boards materials with a boron-free substrate. PGNAA analysis have been carried out for the identification of the best material for the electronics fabrication. A new collimator geometry was also tested in the simulation of the NUANS geometry. Although the new configuration increases signal efficiency, it also increases the neutron-induced background due to the reduced distance from the BSA. A projection imaging simulation was performed for both collimator configurations, and image reconstruction was achieved using an ideal dataset and a modified FLUKA output routine. The results indicate that, although the new collimator improves signal detection, the increased background requires further shielding optimization. These findings provide valuable insights for future detector developments.
La Boron Neutron Capture Therapy (BNCT) è una forma avanzata di radioterapia che si basa sulla reazione nucleare 10B(n,α)7Li per colpire e distruggere selettivamente le cellule tumorali. Uno degli aspetti principali, rivelatosi critico, è il monitoraggio della dose durante i trattamenti BNCT. In questo lavoro sono state condotte simulazioni Monte Carlo, utilizzando il codice FLUKA, per replicare la sessione sperimentale svolta presso l’impianto NUANS a Nagoya, con l’obiettivo di testare un rivelatore SPECT prototipale per il monitoraggio online della dose. Questo dispositivo è progettato con lo scopo di misurare la dose durante il trattamento monitorando i fotoni gamma da 478 keV emessi dalla reazione 10B(n,α)7Li. L’obiettivo principale di questo lavoro è ottimizzare le prestazioni complessive del sistema, attraverso una comprensione dettagliata del segnale di fondo osservato intorno ai 478 keV in assenza di boro nel bersaglio. Lo studio identifica l’origine del segnale di fondo nelle interazioni dei neutroni con il boro contenuto nel materiale delle schede elettroniche del rivelatore e nel cristallo scintillatore. Due strategie di mitigazione sono state proposte e testate via simulazione: un miglioramento della schermatura e la sostituzione dei materiali delle schede elettroniche con un substrato privo di boro. Sono state effettuate analisi PGNAA per l’identificazione del materiale migliore per la realizzazione delle componenti elettroniche. Una nuova geometria del collimatore è stata inoltre testata nella simulazione della geometria NUANS. Sebbene la nuova configurazione aumenti l’efficienza di rivelazione del segnale, essa incrementa anche il fondo indotto dai neutroni a causa della ridotta distanza dal BSA. È stata eseguita una simulazione di imaging per proiezione per entrambe le configurazioni del collimatore, e la ricostruzione dell’immagine è stata ottenuta utilizzando un dataset ideale e una routine modificata di output di FLUKA. I risultati indicano che, sebbene il nuovo collimatore migliori la rivelazione del segnale, l’aumento del fondo richiede un’ulteriore ottimizzazione della schermatura. Questi risultati forniscono indicazioni utili per i futuri sviluppi del rivelatore.
Monte Carlo study and optimization of a SPECT imaging system for BNCT dose monitoring
Mocerino, Gianluca
2024/2025
Abstract
Boron Neutron Capture Therapy (BNCT) is an advanced form of radiotherapy that relies on the 10B(n,α)7Li nuclear reaction to selectively target and destroy tumor cells. One of the main aspect, which turned out to be critical, is dose monitoring during BNCT treatments. In this work, Monte Carlo simulations using the FLUKA code were carried out to replicate the experimental session conducted at the NUANS facility in Nagoya, with the aim of testing a prototype SPECT detector for the online dose monitoring. This device is designed with the goal to measure the dose during treatment by monitoring the 478 keV gamma photons emitted by the 10B(n,α)7Li reaction. The main goal of this work is to optimize the overall performance of the system, through a detailed understanding of the background signal observed near 478 keV in the absence of boron in the target. The study identifies the origin of the background signal in the neutron interactions with boron, contained in the material of the detector’s electronic boards, and with the scintillator crystal. Two mitigation strategies were proposed and tested via simulation: improved shielding with and substitution of the electronics boards materials with a boron-free substrate. PGNAA analysis have been carried out for the identification of the best material for the electronics fabrication. A new collimator geometry was also tested in the simulation of the NUANS geometry. Although the new configuration increases signal efficiency, it also increases the neutron-induced background due to the reduced distance from the BSA. A projection imaging simulation was performed for both collimator configurations, and image reconstruction was achieved using an ideal dataset and a modified FLUKA output routine. The results indicate that, although the new collimator improves signal detection, the increased background requires further shielding optimization. These findings provide valuable insights for future detector developments.| File | Dimensione | Formato | |
|---|---|---|---|
|
2025_07_Mocerino_Executive_Summary_02.pdf
non accessibile
Descrizione: Executive summary
Dimensione
2.09 MB
Formato
Adobe PDF
|
2.09 MB | Adobe PDF | Visualizza/Apri |
|
2025_07_Mocerino_Tesi_01.pdf
non accessibile
Descrizione: Testo tesi
Dimensione
15.72 MB
Formato
Adobe PDF
|
15.72 MB | Adobe PDF | Visualizza/Apri |
I documenti in POLITesi sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
https://hdl.handle.net/10589/240524