The research aims to study the molecules and structures in human skin by the image formation of harmonic-based in vivo optical virtual biopsy.

In the research, the investigators use the Cr:forsterite laser as the light source, and utilize the nonlinear optical microscopic system to observe human skin via in vivo detection. In this study, images of human skin tissue will be acquired by virtual section to truly evaluate the feasibility of this system in clinical application.

This research intends to conduct the following research:

1. To study the feasibility of this technology to observe melanin in the skin: As melanin is THG-bright, the technology will help to explore the distribution and change of melanin in the skin.
2. To study the capability of this technology in the early diagnosis of skin cancers, including melanoma, basal cell carcinoma, and squamous cell carcinoma: By obtaining skin images of healthy and diseased patients, we can establish an image database of normal and cancerous skin in different atages, and evaluate the efficacy of this technology for early diagnosis of skin malignancy in the future.
3. To study the ability of this technology to observe and analyze the degree of skin aging: Optical sectioning of human skin in a non-invasive in vivo manner can be used to detect the microscopic changes of skin aging and solar damage, and to find out the indicators of skin aging, so as to be used in the future to assist the therapeutic analysis of anti-skin aging treatment.
4. To study the ability of this technology to observe peripheral vasculopathy and molecular changes of microvascular structures in diabetic patients: Perform microscopic imaging on healthy and diabetes patients' skin to observe effects of structures and molecules in their skin, such as peripheral vasculopathy in diabetic patients, and the status of disease parameters, with a view to find the cause of peripheral vascular lesions and other biological information.

Inclusion Criteria:

1. healthy volunteers of different skin colors and different ages
2. patients with suspected melanoma
3. patients with suspected basal cell carcinoma or squamous cell carcinoma
4. patients with diabetes mellitus

Exclusion Criteria:

1. volunteers have infectious disease
2. volunteers' skin have been infected with ulceration