A novel medical robot assisting photodynamic therapy for port wine stains

Port wine stain (PWS) birthmarks are congenital vascular malformations, which usually appear at birth and tend to become darker and thicker with age's growth. Vascular-targeted photodynamic therapy (PDT) is an effective approach in the treatment of PWS. However, due to the arbitrariness of manual operation and pole points existing in laser radiation, the PWS zone was always cured unevenly in clinics. So we developed a novel robotic system which consists of a passive arm and an active wrist, to assist doctors in exerting PDT treatments. The passive joints are easy to interaction with doctors, safer and more convenience; the active joints can automate the PDT so that the doctors can focus more on clinical judgements and treatments rather than heave manual works. In this paper, the mechanism of PWS and its treatments were described in brief, and then the robotic system including the detailed robot mechanical design and kinematic analysis was discussed based on the requirements of PDT. Finally, the robot feasibility was validated by experimental results.