A high-throughput comparative characterization of laser-induced soft tissue damage using 3D digital microscopy

Abstract

3D digital microscopy was used to develop a rapid alternative approach to quantify the effects of specific laser parameters on soft tissue ablation and charring in vitro without the use of conventional tissue processing techniques. Two diode lasers operating at 810 and 980 nm wavelengths were used to ablate three tissue types (bovine liver, turkey breast, and bovine muscle) at varying laser power (0.3, 1.0, and 2.0 W) and velocities (1-50 mm/s). Spectrophotometric analyses were performed on each tissue to determine tissue-specific absorption coefficients and were considered in creating wavelength-dependent energy attenuation models to evaluate minimum heat of tissue ablations. 3D surface contour profiles characterizing tissue damage revealed that ablation depth and tissue charring increased with laser power and decreased with lateral velocity independent of wavelength and tissue type. While bovine liver ablation and charring were statistically higher at 810 than 980 nm (p < 0.05), turkey breast and bovine muscle ablated and charred more at 980 than 810 nm (p < 0.05). Spectrophotometric analysis revealed that bovine liver tissue had a greater tissue-specific absorption coefficient at 810 than 980 nm, while turkey breast and bovine muscle had a larger absorption coefficient at 980 nm (p < 0.05). This rapid 3D microscopic analysis of robot-driven laser ablation yielded highly reproducible data that supported well-defined trends related to laser-tissue interactions and enabled high throughput characterization of many laser-tissue permutations. Since 3D microscopy quantifies entire lesions without altering the tissue specimens, conventional and immunohistologic techniques can be used, if desired, to further interrogate specific sections of the digitized lesions.

Comparison of diode laser in soft tissue surgery using continuous wave and pulsed modes in vitro

“…Numerous investigations on the interaction between diode lasers and soft biologic tissues are available [12][13][14][15][16][17][18]26,34]. However, these studies focus on the effectiveness of direct laser surgery, which is difficult to compare with hot-tip surgery.…”

“…Diode laser radiation with a wavelength of (980 AE 10) nm is one of the most widely used lasers in dentistry and dermatology [14][15][16][17][18]. The average power of these lasers for medical application does not exceed 10-15 W [12][13][14][15][16][17][18], with rare exceptions [20,21].…”

“…In recent years, the use of radiation from diode [1,7,[11][12][13][14][15][16][17][18][19] and fiber [1,19] lasers for soft tissue surgery has attracted considerable interest. Diode laser radiation with a wavelength of (980 AE 10) nm is one of the most widely used lasers in dentistry and dermatology [14][15][16][17][18].…”

“…Lasers are widely used for soft tissue surgery [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], because they effectively cut soft tissues with good hemostasis [1][2][3]. CO 2 lasers (l = 10.6 μm) are considered the most popular gas lasers [1,[4][5][6][7].…”

Quantitative investigation of laser ablation based on real‐time temperature variations and OCT images for laser treatment applications

“…34 Three-dimensional digital microscopy was used to develop a rapid alternative approach for quantifying the effects of specific laser parameters on soft tissue ablation and charring. 35 Furthermore, thermal monitoring has been measured using thermography to analyze temperature development. 36 Robot-assisted laser tissue soldering was evaluated by measuring the tearing forces.…”