Abstract: A device and method are presented that allow for accurate insertion, positioning and withdrawal of a laser fiber/catheter for minimally invasive laser treatment by utilizing a single mark in the form of a continuous spiral on either a fiber jacket or a catheter (introducer) or both. Viewed from a fixed position the frequency of the appearance of the line can be used to regulate the speed of withdrawal either manually, automatically or through a combination of both, i.e., visual speed feedback and manual withdrawal, automatic speed feedback and manual pullback or automatic feedback and withdrawal. The distal spiral end terminates preferentially in a circumferential loop at some distance back from the distal tip of the catheter or fiber jacket to serve as a safety marker to indicate when to stop lasing during withdrawal to prevent accidental exposure of the patient or attending hospital personnel.