In this study, effect of a novel LED-based light source developed for 96-well-plates cell culture applications, was tried on AGS stomach
cancer cell line, in combination with Poly(amido amine) (PAMAM) modified – porhyrin molecule. For each 4 generation of modified
PpIX molecule 5 different concentrations tried. According to results PAMAM molecule doesnt have any photosensitizer property
also didn’t show any toxic effect even if higher concentrations. Morphology and real time monitoring analysis results hold up each
other and confirmed that, PpIX molecules with and without modificated high concentrations (>100μM) caused cell death via toxicicity
this reason optimal concentration for PAMAM modified PpIX should be between 25 - 50 μm concentration .
Lasers of different wavelengths are being used in oral surgery for incision and excision purposes with minimal bleeding and pain. Among these wavelengths, those close to 2μ yield more desirable results on oral soft tissue due to their strong absorption by water. The emission of 1940 nm Thulium fiber laser is well absorbed by water which makes it a promising tool for oral soft tissue surgery. This study was conducted to investigate the potential of thulium fiber laser as an incisional and excisional oral surgical tool.
Ovine tongue has been used as the target tissue due to its similarities to human oral tissues. Laser light obtained from a
1940 nm Thulium fiber laser was applied in contact mode onto ovine tongue completely submerged in saline solution in vitro, via a 600)μm fiber moved with a velocity of 0.5 mm /s to form incisions. There were a total of 9 groups determined by the power (2,5-3- 3,5 W), and number of passes (1-3-5). The samples were stained with HE for microscopic evaluation of depth of ablation and extent of coagulation.
The depth of incisions produced with 1940 nm Thulium fiber laser increased with increasing power and number of passes, however an increase in the width of the coagulation zone was also observed.
The aim of this study was to investigate the relation between ablation efficiency and temperature increase during laser
ablation by 1940-nm Tm:fiber laser. The thermal effects of the Tm:fiber laser on the brain tissue was also investigated.
The laser beam (200-1000 mW) was delivered from a distance of 0.5 mm to cortical and subcortical regions of the ex
vivo ovine brain tissue samples via 400 μm optical fiber. A total of 560 brain samples were irradiated at different settings
in continuous-mode or pulsed-mode. In continuous-mode and pulsed-modulated-mode doses were changed with
exposure time and on-off cycles respectively, in order to achieve the tissue to absorb the same energy. During lasing
temperature changes of the irradiated tissue were recorded by a thermoprobe (thermoprobe is a system which an optical
fiber was embedded into a thermocouple). The radiuses of ablation and coagulation zones were measured under
microscope. The ablation efficiencies (100xablation/coagulation radius) and rates of temperature change were calculated.
A strong correlation between the ablation efficiency and rate of temperature change was presented.
The aim of the study was to find a relationship between laser power, exposure time, ablation efficiency and temperature
increase during laser brain ablation by Thulium fiber laser. The thermal effects of the 1940-nm Tm-fiber laser on the
brain tissue was also investigated in terms of ablation efficiency. These experiments are very important in order to model
temperature increase-ablation efficiency during lasing with different power and exposure time. 4-5 mm coronal sections
were taken from lamb brains. Laser was applied at cortical and subcortical tissue with 0-0.1 mm distance, in both
continuous and pulsed modes with 400 mW and 600 mW which were chosen by a predosimetric study. In continuous and
pulse mode doses were changed with exposure time and on-off cycle respectively, in order to achive the tissue to absorb
same energy. During lasing temperature increases were recorded by a thermoprobe (thermoprobe is a system which a 300
micrometer fiber was embedded into a thermocouple). The radius of ablation and coagulation for each laser application
was recorded by a microscope. By calculating ablation efficiency (100xablation/calculation radius) the appropriate laser
doses were determined for both cortical and subcortical tissue. The maximum ablation efficiency for cortical and
subcortical tissue in both continous and pulsed mode was found for 600 mW. Ablation efficiencies for continuous mode
was superior than the pulsed mode for all laser doses which were studied. Temperature increases showed a significant
differences for continuous and pulse mode operating systems and effect the ablation efficiencies.
The aim of the study was to investigate the thermal effects of the 1940-nm Tm-fiber laser on the dead brain tissue. 4-5
mm coronal sections were taken from lamb brains. Tm-fiber laser was applied at the back (cortical) and below the cortex
(subcortical) of these slices with 0.5 mm distance. At the beginning of the research in order to find appropriate laser
parameter to be compared for 1940-nm Tm-fiber laser, the carbonization and coagulation times of the brain slices were
recorded for each power value, both for cortical and subcortical tissue. The appropriate laser parameters for lamb brain
tissue were selected according to this study. Lasers were applied in both continuous and pulsed modes. In continuous
mode, doses were changed with fixed application time. In pulsed mode, doses were modified with the change in pulse
width. The lesions were detected with microscope. The radius of ablation and coagulation for each laser application was
recorded. By calculating ablation efficiency (100xablation/calculation radius) the aproppriate laser doses were
determined for both cortical and subcortical tissue. The maximum ablation efficiency for cortical tissue in continuous
mode was 200 mW and 600 mW and in pulsed mode was 600 mW and for subcortical tissue maximum ablation
efficiency was found 600 mW in both continuous mode and pulsed mode.
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