Port wine stain (PWS) is a congenital, progressive vascular malformation of the dermis, involving capillaries, and possibly perivenular nerves, that occurs in approximately 0.7% of children. These skin lesions are treated with laser pulses that induce permanent thermal damage to the target PWS blood vessels. However, absorption of laser energy by melanin causes localized heating of the epidermis, which may result in complications, such as hypertrophic scarring or dyspigmentation. Cryogenic spray cooling (CSC) has been used commercially for a few years to overcome this problem, although there is limited understanding of the fluid dynamics and thermodynamics of cryogenic sprays.
This research is in collaboration with Professor Stuart Nelson at the Beckman Laser Institute and Medical Clinics, UCI. We focus studies and experiments targeted towards an understanding of the fundamental factors that influence CSC efficiency, both in terms of cooling selectivity within the skin and the optimization of cryogen sprays. By understanding, modeling, and controlling the atomization process of cryogenic sprays, we can optimize the total cooling efficiency.