If your doctor thinks you have an ulcer, you may have to swallow a special camera called an endoscope to find out for sure. The good news: in about a year doctors may be able to quickly and painlessly cure the ulcer at the same time, thanks to a device from Boston, MA-based startup LumeRx. The company is developing a fiber-optic device that can be passed into the stomach alongside the endoscope. In a procedure that takes only five to 10 minutes, the device beams out blue light specially tuned to kill a bacterium called Helicobacter pylori, which causes up to 90 percent of ulcers. Should the approach prove itself in human tests planned for this summer and gain U.S. Food and Drug Administration approval, it could offer an alternative to today’s standard ulcer treatment: a one- to two-week course of antibiotics that can cause nausea and other side effects and which could ultimately promote the development of resistant strains of bacteria.