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Updated: Jul 18, 2026
Measuring Real-time Drug Response in Organotypic Tumor Tissue Slices
Published on: May 2, 2020
Tumor viability using real-time spectral images
Koji Asai1, Yoshinobu Sumiyama, Manabu Watanabe
1Third Department of Surgery, Toho University School of Medicine, 2-17-6 Ohashi, Meguro-ku, Tokyo 153-8515, Japan.
Purpose:
We observed real-time spectral images using line-scan imaging spectrography in order to evaluate tumor viability.
Methods:
Japanese albino rabbits, which underwent the implantation of VX2 tumor strain, were used as subcutaneous tumor models (n = 54). Photodynamic therapy (PDT) consisted of semiconductor laser irradiation of the tumorous lesion. The experimental groups consisted of a PDT group (n = 15) and a non-PDT group (control group, n = 15). The spectral images taken by a CCD camera underwent computer processing. Next, the spectrum of the tumorous lesion was observed and the peak spectrum value was measured.
Results:
Two peaks (545 and 575 nm) corresponding to the absorbance spectrum of oxygenated hemoglobin (oxyHgb) were observed in the untreated area. In the treated area, however, they disappeared and a different peak (560 nm) corresponding to the absorbance spectrum of deoxygenated hemoglobin was observed. PDT induced ischemic tissues and the cells could be confirmed in real time in vivo in monochrome and color images reflecting the oxyHgb amount. A histopathological examination and phosphotungstic acid hematoxylin staining demonstrated diffuse fibrin accumulation in the microvessels, while proliferating cell nuclear antigen staining showed a reduced nuclear stainability.
Conclusions:
These results demonstrated that the real-time spectral images showed the actual histological conditions such as a blocked tumor blood flow and reduced tumor viability.
