Tumor viability using real-time spectral images.
OBJECTIVE
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.
Asai
Koji
K
Third Department of Surgery, Toho University School of Medicine, 2-17-6 Ohashi, Meguro-ku, Tokyo 153-8515, Japan.
Sumiyama
Yoshinobu
Y
Watanabe
Manabu
M
Aizawa
Katsuo
K
D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000473:pathology*; D018450:Disease Progression; D008297:Male; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000473:pathology*; D010778:Photochemotherapy / Q000379:methods; D017319:Photosensitizing Agents / Q000627:therapeutic use; D011166:Porphyrins / Q000627:therapeutic use; D011817:Rabbits; D012878:Skin Neoplasms / Q000188:drug therapy / Q000473:pathology*; D013053:Spectrophotometry / Q000379:methods; D016896:Treatment Outcome
D017319:Photosensitizing Agents; D011166:Porphyrins; C053434:Talaporfin