Treatment of nevus using medical tattooing.
Medical tattooing is used to color skin with a pigment loss. Currently, however, a trial-and-error scheme is employed to obtain the desired color appearance of tattooed skin because prediction of the color appearance is dependent on the experiences of medical doctors. We propose a method for predicting the color appearance of tattooed skin. Two trial dyes are first injected in the area of pigment loss, and the color appearance of a third dye to be injected can be predicted using measured spectrocolorimeter data and mathematical formula. The spectrocolorimeter measures the color appearances of the skin before and after tattooing using the first two dyes, and the mathematical formula calculates the color appearance of the tattooed skin using any third dye. In the derivation of the mathematical formula, light propagation in the skin has been modeled using the modified Lambert-Beer law considering the strong scattering of light by biological tissues. The proposed method was successfully validated by a preliminary tattooing of the skin to an area with pigment loss. Predicting the color appearance of tattooed skin significantly reduces the number of trial-and-error attempts required in the current methods. Medical tattooing using this method can also be applied to treat various skin color abnormalities such as leukoderma, intradermal nevi, and reconstructed nipples.