Hsien-Yi Chiu1,2,3, Chih-Chieh Chan3, Tsen-Fang Tsai4. 1. Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan. 2. Department of Dermatology, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, Taiwan. 3. Department of Dermatology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. 4. Department of Dermatology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. tftsai@yahoo.com.