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La prima immagine dell'organismo in azione (quello di un topolino) ottenuta con la tomografia a emissione di positroni (PET) compie 40 anni. La tecnica utilizza le particelle di antimateria — "specchio" degli elettroni — e permette di osservare i processi fisiologici.
A differenza altri sistemi, come la TAC e la risonanza magnetica (che evidenziano alterazioni anatomiche), questo consente di individuare modifiche a livello metabolico che spesso precedono l'alterazione morfologica. Per farlo utilizza molecole usate come marcatori, in genere zuccheri legati a sostanze radioattive, assorbiti diversamente dai tessuti in base alla loro attività metabolica. Può essere considerata, quindi, una radiografia molto sofisticata che invece dei raggi X sfrutta le caratteristiche dei positroni.
L'idea è figlia della fisica delle particelle ed è nata al CERN di Ginevra, che nel suo sito pubblica la prima istantanea di questo genere.
Ansa/px
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