Influence of External Chromophore on Cutting Efficacy of 940 nm Diode Laser: An In vitro Animal Tissue Study

BACKGROUND: High-power level lasers used in health sciences have important photothermal effect. The maximum absorption of the diode laser correlates with the absorption range of hemoglobin, suggesting that red color may be the required chromophore. Hence, we hypothesized that by providing artificial external red chromophore, we can improve the cutting efficiency of diode laser in noninflamed tissue. The aim of the present study was to assess the efficacy and collateral thermal damage produced by a 940 nm diode laser on stained and unstained porcine tissue sample. MATERIALS AND METHODS: Eight porcine meat samples of specific dimensions were divided into four groups of two pieces each. Group I was stained with beetroot extract, Group II stained with 3% erythrosine dye, Group III stained with hibiscus extract, and Group IV left unstained. A 940 nm diode laser was used at 1.2 W in an intermittent wave mode, to make a standardized dimension incision in all the samples. One sample from each group was stored in 10% formalin and sent for histopathological examination to evaluate the depth and width of incision and amount of lateral thermal damage. The other sample from each group was observed under video profilometer to evaluate the surface characteristics. RESULTS: Staining of tissues with external chromophore using 3% erythrosine dye improved the efficacy of 940 nm diode laser, as evidenced from the sharper, wider cuts and clean incision with minimal charring as compared to beetroot, hibiscus, and saline. CONCLUSION: The use of staining can be an adjunct to the lasers in improvement of efficacy.