Real-time IR700 Fluorescence Imaging During Near-infrared Photoimmunotherapy Using a Clinically-approved Camera for
Shuhei Okuyama1,2, Daiki Fujimura1,2, Fuyuki Inagaki2
1Shimadzu Corporation, Kyoto, Japan.
Background/Aim:
Near-infrared photoimmuno-therapy (NIR-PIT) is a newly approved cancer phototherapy. We aim to confirm whether a clinically approved camera for indocyanine green (ICG) could monitor IR700 fluorescence in real time during exposure to therapeutic NIR light.
Materials And Methods:
An NIR camera, LIGHTVISION, designed to image ICG fluorescence, was used. A431-GFP/luc tumor-bearing mice were exposed to therapeutic NIR light and real-time fluorescence imaging (RT-FI) was obtained and measured with LIGHTVISION. Bioluminescence imaging (BLI) was performed to confirm cell death.
Results:
RT-FI during NIR-PIT revealed an initial rapid loss of fluorescence, followed by a plateau which occurred at a light dose of approximately 30 J/cm . Correlation between BLI and IR700 fluorescence loss showed that loss of fluorescence was associated with increased cell death.
Conclusion:
The efficacy of NIR-PIT could be monitored non-invasively and in real-time using weak fluorescence at wavelengths much longer than the peak fluorescence of IR700. This technique can achieve precise light dosimetry that allows us to decide on the optimal exposure.
