Plenoptic cameras enable capture of directional light ray information, thus allowing applications such as digital
refocusing, depth estimation, or multiband imaging. One of the most common plenoptic camera architectures contains a
microlens array at the conventional image plane and a sensor at the back focal plane of the microlens array. We leverage
the multiband imaging (MBI) function of this camera and develop a single-snapshot, single-sensor high color fidelity
camera. Our camera is based on a plenoptic system with XYZ filters inserted in the pupil plane of the main lens. To
achieve high color measurement precision of this system, we perform an end-to-end optimization of the system model
that includes light source information, object information, optical system information, plenoptic image processing and
color estimation processing. Optimized system characteristics are exploited to build an XYZ plenoptic colorimetric
camera prototype that achieves high color measurement precision. We describe an application of our colorimetric camera
to color shading evaluation of display and show that it achieves color accuracy of ΔE<0.01.
In order to investigate the interaction between the triplet state T1 and ground state oxygen 3O2 during pulsed
excitation photodynamic therapy (PDT), we measured the phosphorescence and singlet oxygen 1O2 fluorescence time-resolved
waveform. The phosphorescence time-resolved waveform from clinical photosensitizers has not been
obtained because this signal was buried in the photosensitizer fluorescence. We constructed the experimental setup
with a spectral and temporal filter to select the phosphorescence signals from the Photofrin(II)(R) and Talaporfin sodium
solution. The lifetimes and spectrums of the measured luminescence coincided with the phosphorescence
characteristics, respectively. We obtained the phosphorescence time-resolved waveforms from the clinical
photosensitizer solutions successfully. The 1O2 fluorescence time-resolved waveforms from these photosensitizers
were measured with an IR-PMT with a photon counter. The fluorescence time-resolved waveforms of each
photosensitizer were also obtained by the authors. We could consequently describe sequential generation of three
time-resolved waveforms throughout the photosensitive reaction in the clinical photosensitizers. We think we may
evaluate the photoseisitizer characteristics by these waveforms.
Photodynamic therapy (PDT) is promising modality for cancer. Prostate cancer is the most common cancer in USA. We proposed transurethral prostate cancer treatment using the pulse-intensity-domain depth-controlled PDT to preserve urethra wall. We have found that photocytotoxicity has been suppressed under high-intensity pulsed excitation with the second generation photosensitizers. We aim to apply this effect to form intact portion on the surface of the irradiated field. Irradiation condition dependence of photocytotoxicity of rat prostate cancer cell line R3327-AT-1 was investigated with two clinical photosensitizers, Porfimer sodium and Talaporfin sodium. A pulsed laser was irradiated with the power energy density ranging from 1.25 to 10 mJ/cm2. Near-infrared luminescence from singlet oxygen in the solution of those two photosensitizers was measured transiently. We performed PDT against a rat subcutaneous prostate tumor mode with Talaporfin sodium (2mg/kg) injected intravenously 1 h prior to the irradiation. The laser was irradiated with the power energy density 2.5 or 10 mW/cm2, with the total fluence of 50 J/cm2. Photocytotoxicity in vitro and the singlet oxygen generation were both suppressed with the 10mJ/cm2 irradiation with Talaporfin sodium, while these with Porfimer sodium were kept relatively constant. The surface of the irradiated field of 1mm in thickness remained intact, while the tumor damaged layer of 1.3 mm in thickness was obtained in the case of 10mJ/cm2 irradiation. We think Talaporfin sodium has high sensitivity to the pulse energy density, which might be useful to realize urethra preserved PDT for prostate cancer.
Photodynamic therapy against murine macrophage like cells with the second-generation hydrophilic photosensitizer ME2906 (mono-L-aspartyl chlorin e6:NPe6) was performed in vitro to study therapeutic effect distribution formation along depth with high-intensity pulsed irradiation. The photocytotoxicity of macrophage like cell with ME2906 under various fluence rates was measured. We found photocytotoxicity suppression from 64% to 16% in the cell lethality ranging the fluence rate of a pulsed laser from 20 to 400mW/cm2 (corresponding pulse peak power: from 0.07 to 1.4 MW/cm2). The cell lethality of about 80 % was obtained with continues wave laser irradiation under the fluence of 10 J/cm2. Photobleaching and oxygen consumption of the photosensitizer solution, were measured to know photoreaction of the photosensitizer solution under the high fluence rate pulsed irradiation. Type-II photochemical reaction suppression was indicated with the high fluence rate pulsed irradiation. The transient absorption of the photosensitizer solution during pulse irradiation was measured by the pump-and-probe technique with pulse peak power density up to 1.2 MW/cm2 to investigate absorption saturation. In the case of the pump beam peak power of 1.2MW/cm2, the transmittance of the probe beam increased approximately 7% from that of without the pump beam, so that huge absorption saturation did not occur in this case. We think the main cause of the photocytotoxicity suppression in this study may not to be attributed to the absorption saturation. This photocytotoxicity suppression induced by the high-intensity irradiation may be available to control treatment depth of PDT to preserve healthy internal wall of a hollow organ.
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