Development and clinical evaluation of medical robot assisted photodynamic therapy of port wine stains

Background Port wine stains (PWS) are a kind of skin disease for which photodynamic therapy (PDT) has already achieved good results. With manual operation of clinical PDT, the laser density is uneven and laser irradiation of the lesion is arbitrary and non-uniform. In addition, lengthy manual operation tires doctors; thus a robot system has been developed to assist them. Methods First, a novel medical manipulator consisting of five passive joints (robot arm) and two active joints (robot wrist) was developed to automatically improve the uniformity of laser irradiation. Second, image processing of the lesion was introduced. Third, kinematics and path planning of the robot were analysed, and safety precautions were introduced. Then, accuracy tests of the robot wrist and robot system were conducted separately before clinical application. Finally, a total of 50 PWS cases were treated using the robot system. The clinical outcomes and comparison of non-parametric values were employed to evaluate the robot system. Results The accuracies of the robot wrist and robot system were shown to meet the requirements of clinical PDT treatment. The robot system performed successfully in 50 PWS cases. Doctors can devote more energy to clinical judgments during treatment with the assistance of the robot system. All the PWS have shown different degrees of improvement. The results show that the robot system is useful in assisting doctors for the PDT treatment of PWS. Conclusions The experiments show the feasibility and usefulness of the robot system in assisting doctors giving PDT treatment for PWS. The robot system can lighten the load on doctors and improve the therapeutic effect. Copyright © 2011 John Wiley & Sons, Ltd.