The idea that led to a major advancement in laser surgery originated with Dr. J. Stuart Nelson at UC Irvine in 1992 while he was watching a baseball game. At the time, Nelson and his colleagues at the Beckman Laser Institute & Medical Clinic (BLIMC) were working to improve laser treatments for vascular birthmarks, particularly port-wine stains in infants and children.
The main challenge they faced was that lasers could damage the outer layer of skin, causing pain and scarring, while not effectively targeting the deeper blood vessels responsible for birthmarks. Previous attempts to cool the skin before laser exposure using ice cubes, cold water, or chilled metal plates proved ineffective because these methods also cooled the targeted blood vessels.
“We needed to get something very cold onto the skin surface in perfect thermal contact and then off the skin surface – all within a fraction of a second,” Nelson said. “I remembered what I saw watching a baseball game.”
Nelson recalled seeing trainers use ethyl chloride spray on injured players during games to numb pain quickly. He shared this idea with postdoctoral researcher Thomas Milner and visiting engineer Lars Svaasand over dinner, leading them to consider spray cooling as a potential solution.
By Monday, Milner and Svaasand had constructed a prototype of what would become known as the Dynamic Cooling Device (DCD), using parts from an auto supply store. The team tested it on themselves to determine optimal settings for cryogen spurt duration and timing with laser exposure.
“It was a fairly simple construction,” said Milner, now at Baylor College of Medicine. “That’s the beauty of the invention: It’s so simple and works so well.”
The DCD sprays a nonflammable freon substitute onto the skin just before each pulse of laser light. The coolant evaporates almost instantly, cooling only the top layer of skin without affecting deeper tissues.
“Because the spurt durations are so short, the cooling remains confined to the skin’s most superficial layer and does not affect the deeper targeted blood vessels causing the vascular birthmark,” Nelson explained. “This allows much higher laser light dosages to be used, while at the same time minimizing injury to the skin and pain to the patient.”
Patented in 1998 and licensed to Candela Laser Corp., DCD technology became standard on more than 47,000 Candela lasers worldwide before its patent expired in 2020. The device also appears on other manufacturers’ equipment globally.
Between 2001 and 2010, DCD ranked among the top-earning inventions licensed by institutions within the University of California system. In some years it placed second or third for royalty income generated for UC Irvine.
“The combination of basic research, engineering and clinical testing that went into the Dynamic Cooling Device is exactly what was envisioned over 30 years ago when the idea of the BLIMC was first conceived,” said Michael Berns, Arnold & Mabel Beckman Chair in Laser Biomedicine and institute co-founder.
While DCD-equipped lasers are used for various cosmetic procedures such as hair removal or scar treatment, Nelson emphasized its primary benefit is improving care for patients with port-wine stains: “The technology has made possible the early, painless, safe and effective treatment of port-wine stains and other disfiguring vascular birthmarks in infants and young children in ways that Tom, Lars and I could never have imagined,” he said. “That’s what I’m most proud of.”
