Cryogen spray cooling of the tissue surface was investigated for laser welding applications. Benefits include reduced thermal damage to the papillary dermis and reduced operation time. Two-cm-long, full-thickness incisions were made on the backs of guinea pigs, in vivo. India ink was used as an absorber and clamps were used to appose the incision edges. Continuous-wave, 1.06-μm, Nd:YAG laser radiation was scanned over the incisions, producing approximately 100 ms pulses. A 4-mm-diameter laser spot was used with a constant power of 16 W. The total operation time was 60 or 120 s. Cryogen was delivered in spurt durations of 20, 60, or 100 ms, with 2 or 4 s between spurts. The working distance was approximately 12 cm, and the spray covered an area of about 5.0×5.0 cm. Control welds (without cooling) were irradiated for 20, 40, or 60 s. Total operation times were reduced from 10 min without dynamic cooling to 1 min with dynamic cooling. Optimal tensile strength was 1.7±0.4 kg/cm2, comparable to strengths of 2.1±0.7 kg/cm2 reported in previous studies without cryogen cooling (p>0.25). Thermal damage in the papillary dermis measured 320±80 μm.
|Original language||English (US)|
|Number of pages||6|
|Journal||Proceedings of SPIE - The International Society for Optical Engineering|
|State||Published - Jan 1 1999|
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Condensed Matter Physics