Optical mammography is a promising non-invasive technique suitable for monitoring the evolution of neoadjuvant therapy, based on the breast optical properties and its main constituents’ concentrations (blood, water, lipids and collagen). The optical mammograph developed at the Physics Department of Politenico di Milano operates in transmittance geometry, in time domain, at seven different wavelengths in the red and near infrared spectral range (635 – 1060 nm). The measurement acquisition scheme is similar to the one adopted for X-ray mammography. This thesis work describes the improvements made to the instrument, the characterization of its performances and the results of preliminary in vivo measurements. The goal is the preparation to the forthcoming clinical trial at the San Raffaele hospital in Milan, that will aim at tracing the evolution of neoadjuvant therapy and its effects on the patients’ breast composition. The lack of synchronization during measures between the data acquisition via the system that implements the Time Correlated Single Photon Counting technique and the probe displacement has been solved thanks to the introduction of an external supporting counter. Afterwards, a laboratory study involving five healthy women started in order to verify the robustness and the reproducibility of the whole measurement process, including data analysis. The data collected during the study have been analysed applying the Radiative Transfer Theory for homogeneous media. Results revealed some criticalities, such as the collagen’s reproducibility and a limited scanned area with respect to the effective breast size, the latter solved thanks to the replacement of the acquisition system with another characterized by an higher throughput. The more complex perturbative approach has been examined by means of simulations, so as to optimize the fitting procedure to characterize lesions, in view of the future clinical trial.
La mammografia ottica è una promettente tecnica non invasiva capace di monitorare il decorso della terapia neoadiuvante a partire dalle proprietà ottiche e dalle concentrazioni dei costituenti principali del seno (sangue, acqua, lipidi e collagene). Il mammografo ottico sviluppato presso il Dipartimento di Fisica del Politecnico di Milano opera in trasmissione, nel dominio del tempo, a sette lunghezze d’onda nel rosso e vicino infrarosso (635 – 1060 nm), in una configurazione simile a quella della mammografia a raggi X tradizionale. In questo lavoro di tesi si descrivono la finalizzazione strumentale, la caratterizzazione delle prestazioni dello strumento e i risultati di misure preliminari in vivo. L’obiettivo è la preparazione all’imminente trial clinico presso l’ospedale San Raffaele di Milano, volto a seguire l’evoluzione della terapia neoadiuvante e gli effetti prodotti sulla composizione del seno delle pazienti. La mancanza di sincronizzazione durante una misura tra l’acquisizione dei dati da parte del sistema che implementa la tecnica del conteggio di singoli fotoni correlati nel tempo e lo spostamento della sonda è stato risolto grazie all’introduzione di un contatore esterno di supporto. Dopodiché, ha avuto inizio uno studio di laboratorio che ha coinvolto cinque donne sane, al fine di verificare la robustezza e la riproducibilità dell’intero processo di misura, compresa l’analisi dei dati. I dati raccolti durante lo studio in laboratorio sono stati analizzati applicando la Teoria del Trasporto Radiativo per mezzi omogenei. I risultati hanno evidenziato alcune criticità, come la riproducibilità del collagene e una ridotta area di scansione rispetto alle dimensioni effettive del seno, quest’ultima risolta grazie alla sostituzione del sistema di acquisizione con uno dalla capacità di trasmissione maggiore. È stato esaminato anche il più complesso approccio perturbativo tramite delle simulazioni mirate a ottimizzare la procedura di fitting per caratterizzare le lesioni tumorali, in vista del futuro studio clinico.
Time-resolved seven-wavelength optical mammography : from instrument upgrade to initial in vivo tests
MAFFEIS, GIULIA
2018/2019
Abstract
Optical mammography is a promising non-invasive technique suitable for monitoring the evolution of neoadjuvant therapy, based on the breast optical properties and its main constituents’ concentrations (blood, water, lipids and collagen). The optical mammograph developed at the Physics Department of Politenico di Milano operates in transmittance geometry, in time domain, at seven different wavelengths in the red and near infrared spectral range (635 – 1060 nm). The measurement acquisition scheme is similar to the one adopted for X-ray mammography. This thesis work describes the improvements made to the instrument, the characterization of its performances and the results of preliminary in vivo measurements. The goal is the preparation to the forthcoming clinical trial at the San Raffaele hospital in Milan, that will aim at tracing the evolution of neoadjuvant therapy and its effects on the patients’ breast composition. The lack of synchronization during measures between the data acquisition via the system that implements the Time Correlated Single Photon Counting technique and the probe displacement has been solved thanks to the introduction of an external supporting counter. Afterwards, a laboratory study involving five healthy women started in order to verify the robustness and the reproducibility of the whole measurement process, including data analysis. The data collected during the study have been analysed applying the Radiative Transfer Theory for homogeneous media. Results revealed some criticalities, such as the collagen’s reproducibility and a limited scanned area with respect to the effective breast size, the latter solved thanks to the replacement of the acquisition system with another characterized by an higher throughput. The more complex perturbative approach has been examined by means of simulations, so as to optimize the fitting procedure to characterize lesions, in view of the future clinical trial.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/148893