(A) development of robot-assisted laser treatment system with clinical trials

Abstract

For optimal laser treatment, uniform distribution of laser delivery is essential. Research and development are conducted to compensate for the difficulties faced by physicians in tracking the exact location under irradiation by the laser because the duration of the laser flash is less than 300 ms, and the laser leaves no trace after irradiation. For laser treatment on large areas, physicians are likely to lose focus owing to the simplicity and tediousness of the procedure along with fatigue because of prolonged hours of operation. To remedy these difficulties and achieve uniform laser delivery, two methods are proposed

one uses the automatic robot-assisted method and the other involves training physicians to increase their proficiency. Both methods are introduced here, but the automatic method is emphasized in this study. A robot-assisted laser treatment system is composed of a commercial laser hair removal device, laser distance sensor, and high-resolution webcam attached at the end-effector of a six-axis robot arm. The software system is operated and provides visual information through a graphical user interface (GUI). The proposed system can detect an arbitrary shape of any size in red as a target for laser delivery and perform uniform distribution of laser irradiation on it. The system also contains a safety measurement system that both the patient and physician could pause and resume at will. The localization-error test and area-per-spot test produced satisfactory outcome averages of 1.04 mm error and 38.22 mm2/spot, respectively. Clinical trials were conducted on six males aged 20-40 years. The treatment schedule comprised of four visits for treatment and the fifth visit only for a photograph session

subjects were photographed and shaved, and they received laser hair removal treatment on their laps (one by the system and the other by the physician) during the first through fourth visits at two-week intervals. All subjects successfully completed the clinical trial with no noticeable or permanent side-effects. In terms of effectiveness comparison, the automatic system demonstrated an average hair removal rate of 49% (standard error of the mean [SEM]:4.0) while the physician achieved 29.5% (SEM: 4.0) under the same conditions. The average treatment duration and number of irradiation shots were 18 min, 30 s (SEM: 33 s) and 260 (SEM: 5.7), respectively, for the system and 3 min 11 s (SEM: 15 s) and 73 (SEM: 5.9), respectively, for physician-treatment. The system provided a near to idealistic number of irradiation shots, while the physician unsuccessfully completed the trials by providing an insufficient number of shots. As most of laser treatment shares similar characteristics of difficulties, the proposed system is expected to be widely used in the field of low-level laser treatment.