A method and device for improved minimally invasive vascular treatments. An exemplary retainer ring includes a vertical wall disposed at a radius about a central axis and a laser diode module that includes a lens to emit visible radiation as a fan-beam. The switching controller includes a modulator connected to a control electrode of the switch and that is adapted to actuate and deactuate the switch, and a first timer that is connected to the switching node and to the modulator. The second mirror is configured to reflect the image reflected from the first mirror. The controller is programmed with a parameter for the amount of fluid to be dispensed. The predetermined number of batch of film deposition processes is calculated based on a film deposition-related operating time and a cleaning-related operating time.