Emil Sobol | PubMed Health

PubMed2003

Time-resolved, light scattering measurements of cartilage and cornea denaturation due to free electron laser radiation.

Light scattering is used to monitor the dynamics and energy thresholds of laser-induced structural alterations in biopolymers due to irradiation by a free electron laser (FEL) in the infrared (IR) wavelength range 2.2 to 8.5 microm. Attenuated total reflectance (ATR) Fourier-transform IR (FTIR) spectroscopy is used to examine infrared tissue absorption spectra before and after irradiation. Light scattering by bovine and porcine cartilage and cornea samples is measured in real time during FEL irradiation using a 650-nm diode laser and a diode photoarray with time resolution of 10 ms. The data on the time dependence of light scattering in the tissue are modeled to estimate the approximate values of kinetic parameters for denaturation as functions of laser wavelength and radiant exposure. We found that the denaturation threshold is slightly lower for cornea than for cartilage, and both depend on laser wavelength. An inverse correlation between denaturation thresholds and the absorption spectrum of the tissue is observed for many wavelengths; however, for wavelengths near 3 and 6 microm, the denaturation threshold does not exhibit the inverse correlation, instead being governed by heating kinetics of tissue. It is shown that light scattering is useful for measuring the denaturation thresholds and dynamics for different biotissues, except where the initial absorptivity is very high.

Absorption↗

PubMedDate not supplied

Laser septochondrocorrection.

OBJECTIVE: To present results from a clinical series of patients who underwent office-based laser nasal septal cartilage reshaping. DESIGN: Nonrandomized prospective clinical trial. SETTING: Outpatient university-based otolaryngology clinic. PATIENTS: One hundred ten patients aged 11 to 66 years with symptomatic nasal obstruction due to septal deviation. INTERVENTION: Topical anesthesia (10% lidocaine solution) was applied to the nasal cavity. The septum was then mechanically straightened using a modified nasal speculum, and it was secured in a median position. Laser energy from a holmium:YAG laser was delivered via an optical fiber to the septum along the regions of maximum mechanical stress. Irradiation was delivered through the mucosa. MAIN OUTCOME MEASURES: A subjective survey, rhinoscopy, and rhinomanometry in 110 patients before and after surgery. RESULTS: Eighty-four patients (76%) showed stable improvement in airways and disappearance of the attendant symptoms. The average duration of follow-up was 18 months. CONCLUSIONS: This technique uses local, nondestructive laser irradiation to reshape septal deviations without the use of mucoperichondrial flaps or sedation.

Adolescent↗