Design of a combined passive and active joints robot assisting photodynamic therapy for port wine stains

Port wine stain (PWS) birthmarks are congenital vascular malformations, which usually appear at birth. Vascular-targeted photodynamic therapy (PDT) is an effective approach in the treatment of PWS with laser. In clinical, the laser irradiation, which is operated by manual, can´t be quantified and is not scientific. This paper presents a novel robotic system, which consists of a passive arm and an active wrist to assist doctors to exert PDT treatments. In clinics, compared to the fully actuated robot, the passive arm is more convenient and safer to operate; the two Degrees of Freedom (DOFs) active wrist can automate PDT under the guidance of binocular vision, so the doctors can focus more concentration on clinical judgments and treatments rather than do heavy manual work. This paper, first, introduced the mechanism of PWS and its treatments. Based on the prosperities of PDT, we designed the robotic system architecture, which consists of the medical robot, binocular vision and workstation. Then the detailed mechanical design on the robot with combined passive and active joints was given. Experimental results have showed that the robotic system could reduce much more workburden and realize more uniform radiation than manual work could.