Experimental investigation of the oxygen sensing ability of positron annihilation spectroscopy for tumor imaging

The potential biomedical application of Positron Annihilation Spectroscopy (PAS) for nonstructural characterization of normal and cancer cells was not thoroughly employed and researched. In this paper, the experimental investigation of the oxygen sensing ability of the PAS technique for tumor imaging is presented and discussed. This research is based on the validated hypothesis that tumor cells differ from the normal tissues in their value of oxygen concentrations. The components of Doppler Broadening and positron annihilation lifetime spectra are measured with our homemade spectrometer to determine the mechanism behind the positron annihilation in oxygen content tissue-equivalent samples. The analysis of PAS data shows that the Orbital Momentum Spectrum (OEMS) of the Coincidence Doppler Broadening Spectroscopy (CDBS) and the positronium lifetime components of Positron Annihilation Lifetime Spectroscopy (PALS) are sensitive to the presence of oxygen. The results are applicable in the development of a tumor imaging system based on the PAS technique.