Photodiagnosis Photodyn Ther. 2016 Sep;15:100-4. doi: 10.1016/j.pdpdt.2016.06.004.

Developing a dermatological photodiagnosis system by optical image analyses and in vivo study.

The dual absorption wavelengths of a photosensitizer usually locate at 370-440 nm and 600-750nm, and most of the dermatologist use the light sources from these two wavelengths to cure the lesion on epithelial tissue, such as Actinic keratosis, Bowen’s disease, oral verrucous carcinoma. However the recurrence rate is still high after giving the Photodynamic therapy for skin cancer. The authors have completed experiences to develop 395-nm LED ring lights with a close-up photograph device to capture finger’s images for crime scene investigation. We followed absorption wavelengths of a photosensitizer (Chlorin e6) and transferred the technology into 375-nm LED ring lights, then developed a portable system with 375nm irradiation to improve the enlarged and clear fluorescence imaging for photodiagnosis (Figure 1). The in vitro results showed the image reproducibility value is higher than 99.0%, the imaging interference made by external light sources is lower than 3.0%. In vivo study shows the Chlorin e6 red fluorescence and the scope of distribution of B16-F10 melanoma cells in the ear’s vein can be measured clearly. The soft-start in the LED-driver IC for violet regions needs more considerable time for spectral emission to capture images in in vivo study. This device has obtained the medical license from Taiwan government, in clinical photodiagnosis this 375-nm based camera can identify the Brown’s diseased tissues (Figure 2) and demarcating the margin of normal tissues.
Figure 1. 375nm based photographic device.

Figure 2. Photodiagnosis for Brown’s disease.