The use of near infrared (NIR) light for biomedical photonics in the wavelength region between 800 and 2000 nm, which is called “biological window”, has received particular attention since water and biological tissues have minimal optical loss due to scattering and absorption as well as autofluorescence in this region. Recent development of InGaAs CCD enables observations in this wavelength region. In the present paper, we report development of Yb and Er-doped yttrium oxide nanoparticles (Y2O3:YbEr-NP) which show strong NIR emission under NIR excitation (NIR-NIR emission). We also demonstrate that NIR emission can be observed through swine colon wall. Based on these results, we propose a possible application ofY2O3:YbEr-NP for cancer diagnosis and therapy using NIR-NIR imaging system. Our results also suggest potential applications ofY2O3:YbEr-NP for noninvasive detection of various diseases.
Near-infrared diffuse correlation spectroscopy in cancer diagnosis and therapy monitoring
