Photodynamic therapy (PDT) and photodynamic diagnosis (PDD) have been reported to be useful for the treatment of the skin cancers and deciding the lesion. We performed PDT for the treatment of Bowen′s disease and cutaneous T-cell lymphoma, and PDD for deciding the lesion of extramammary Paget′s disease, using 20% 5-aminolevulinic acid (ALA) in the past 5 years. We had a relapse in each case performing PDT for the treatment of Bowen′s disease and cutaneous T-cell lymphoma, whereas PDD was useful deciding the accurate lesion of extramammary Paget′s disease and detecting remaining Paget′s cells. We have to recognize limitations of PDT and PDD, and make a deliberate case selection.

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It has been reported that low-power laser irradiation (LLI) demonstrated efficacy in treating patients with various pain syndromes and in a number of pain models. The characteristics of such effects and exact underlying mechanism, however, are still unknown. In the present study, we examined the effects of LLI on sensory responses of frog cutaneous nerve to tactile or pain stimulation to the dorsal skin surface. Fifteen frogs (Xenopus laevis) were used. They were anesthetized and immobilized by cooling, and their dorsal skins with 3-5 cutaneous nerves were prepared. Multi-unit activity from a sensory nerve bundle was recorded during the tactile or pain stimulation which was applied to its receptive field for 5 s each. Such stimulation was repeated three times before and during LLI (CW; 532 or 808 nm; 60 mW; 28.3 mm²). The multi-unit activity was discriminated every 0.2 mV based on amplitude histogram, selected with the responsiveness (larger than 5 impulses to one stimulus), and classified into 5 types (TS: tactile-specific, TD: tactile-dominant, PS: pain-specific, PD: pain-dominant, and others) according to difference of responses between tactile and pain stimulation. The number of TS, TD, PS, and PD type were 8, 26, 17 and 35, respectively. The 532 nm LLI suppressed unit responses of all 4 types and significantly decreased them from the control level (100%) before LLI to the level of 6-55% during LLI (p<0.01). The 808 nm LLI also decreased sensory responses of 4 types to the level of 23-50% (p<0.01). It is concluded that the LLI has a potential to suppress the sensory nerve responses, although such effectiveness does not show wavelength-dependency as well as stimulus-selectivity.

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HPV infection causes benign lesion such as condyloma or malignant lesion such as cervical cancer depending on HPV genotype. Therapeutic methods against condyloma are medication and surgical treatment, but effectiveness of PDT against condyloma is not clear.
We report here a 34-years-old case with both CIS and condyloma of the uterine cervix at the same time. Both HPV (Human papilloma virus) type 6 and 16 were detected by using HPV genotyping method, i.e., Amplicore linear array. We treated that patient by PDT after obtaining the informed consent from her and her family. The therapeutic effect of PDT was rated as CR (complete response) and HPV viruses were not detected 6 months after PDT. She had no recurrence for one year after PDT. Simultaneous infection of high- and low-risk HPVs at the uterine cervix might have caused CIS and condyloma at the same time. It was suggested that PDT might be effective on the case with CIS even complicated with condyloma of the uterine cervix.

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In the 1990′s, autofluorescence bronchoscopy was developed as an imaging modality, initially to examine the bronchus using intensity differences in endogenous fluorescent materials without administering a photosensitizer, and it has been reported to be useful for localizing early stage lung cancer and dysplasia. Its sensitivity for carcinoma in situ and dysplasia has improved, and lesions that previously could not be identified by conventional bronchoscopy can now be detected. Because autofluorescence diagnosis can accurately establish the range of mucosal progression of cancerous lesions, it is useful for determining the extent of the irradiation target for endoscopic photodynamic therapy or the surgical resection line in the bronchus. However, the current system is insufficient for differentiating early cancer from dysplasia and differentiating these lesions from inflammation. These issues must be addressed in the future.

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The autofluorescence imaging videoendoscopy system (AFI) produces real-time color images from processing of detected natural tissue fluorescence from endogenous fluorophores by light excitation. In this system, autofluoresce is mainly originated from collagen in the submucosa in the digestive tract, and the mucosa looks green in the AFI images. Neoplasia in the esophagus appears purple area in green background. In the stomach, fundic mucosa looks purple whereas pyloric or atrophic mucosa looks green similar to mucosa in the other digestive tract. Therefore, tumors in the fundic mucosa show green areas in purple background, whereas tumors in the pyloric or atrophic mucosa look purple in green background.

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Narrow band imaging is a novel system that can be used to observe microvessel structure using a new narrow banding filter instead of the conventional RGB broadband filter. Wavelength ranges of the new NBI filter were 400-430 nm (Blue), 400-430 nm (Green), and 520-560 nm (Red). The main chromophore in bronchial tissues in the visible wavelength range is haemoglobin, which has a maximum absorptive wavelength near 415 nm, and is within the wavelength range for NBI-Blue and Green (400-430 nm). Increased vessel growth and complex networks of tortuous vessels in squamous dysplasia, some dotted vessels in addition to microvessels, vascular networks of various grades in angiogenic squamous dysplasia and several dotted vessels and spiral type vessels of various sizes and various grades in squamous cell carcinoma were clearly observed in NBI with high resolution bronchovideoscopy. This may enable detect the onset of angiogenesis during multi-step carcinogenesis of the lung.

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Confocal endomicroscopy is a newly developed tool that we can use to observe the GI tract mucosa, and it provides subcellular resolution during ongoing endoscopy. Magnifying endoscopy has recently spread to clinical practice, and this super magnifying endoscopy - - confocal endomicroscopy - - is thought to connect magnifying endoscopy with histology. We can inspect cross-sectional images at a depth of from 0 to 250μm deep with a microscopic field of 475μm×475μm. Using confocal endomicroscopy, we can observe both the surface and the subsurface of cellular and microvessel architecture in the gastrointestinal mucosa after the venous administration of fluorescein sodium. For distinguishing between malignant and benign lesions, we should assess the number of cells, the arrangement of glands, the regularity of glands, the size of microvessels, the diameter of microvessels, and the regularity of microvessels. We can also diagnose the malignant change in inflammatory disease of the GI tract, for example ulcerative colitis or Barrett′s esophagus. Although confocal endomicroscopy has disadvantages such as the inability to observe the nucleus in the living cell or allergy to fluorescein, this modality has great potential for providing breakthroughs in the diagnosis of malignancy or in observing physiological molecular movement in the upcoming era of NOTES (Natural Orifice Tansluminal Endoscopic Surgery) or molecular imaging.

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