Optical coherence tomography with online visualization of more than seven rendered volumes per second.

Nearly real-time visualization of 3-D volumes is crucial for the use of optical coherence tomography (OCT) during microsurgery. With an ultrahigh speed spectral domain OCT coupled to a surgical microscope, on-line display of 7.2 rendered volumes at 87 megapixels per second is demonstrated.

Pilot study in neonates using low-level laser therapy in the immediate postoperative period of myelomeningocele.

Objective: To analyze the tissue repair behavior after corrective surgical incision in neonates submitted to low-level laser therapy, in an attempt to diminish the incidence of postoperative dehiscence following the surgery for myelomeningocele performed immediately after birth.

Methods: It is a prospective pilot study with 13 myelomeningocele patients submitted to surgery at birth who received adjuvant treatment with low-level laser therapy (Group A). Diode laser C.

Monte Carlo Green's function formalism for the propagation of partially coherent light.

We present a Monte Carlo-derived Green's function for the propagation of partially spatially coherent fields. This Green's function, which is derived by sampling Huygens-Fresnel wavelets, can be used to propagate fields through an optical system and to compute first- and second-order field statistics directly. The concept is illustrated for a cylindrical f/1 imaging system.

Laparoscopic repair of inferior vena caval injury using a chitosan-based hemostatic dressing.

Background: Vena caval injury is a rare but serious complication of laparoscopic surgery, and often requires conversion to an open procedure. The current study investigated whether a vena caval injury could be repaired with a chitosan dressing laparoscopically.

Methods: Six domestic swine were studied.

Clinical evaluation of experimentally induced choroidal neovascularizations in pigmented rabbits by subretinal injection of lipid hydroperoxide and consecutive preliminary photodynamic treatment with Tookad.

Purpose: Up to date several approaches have been undertaken to achieve an 'easy-to-handle' animal model of choroidal neovascularizations (CNVs) in rabbits; however, so far in none of the studies could healthy retinal tissue be maintained, which is mandatory to further investigate the effects of photodynamic therapy (PDT) or anti-vascular-endothelial-growth-factor treatments. It was our aim to reevaluate and verify the method of inducing experimental CNVs in rabbits using subretinally injected linoleic acid hydroperoxide (LHP) as proposed by Tamai et al. and to use it for experimental PDT.

Beam-profile modulation of thulium laser radiation applied with multimode fibers and its effect on the threshold fluence to vaporize water.

The threshold fluences at which vaporization is initiated at the tip of a multimode fiber that is submerged in water were investigated when free-running and Q-switched thulium laser pulses (lambda = 2.01 microm) were applied with different pulse energies. We focused on the quantification of temporal and spatial fluence modulations of the beam profile at the tip of a 400-microm fiber.

Influence of optical aberrations on laser-induced plasma formation in water and their consequences for intraocular photodisruption.

The influence of spherical aberrations on laser-induced plasma formation in water by 6-ns Nd:YAG laser pulses was investigated for focusing angles that are used in intraocular microsurgery. Waveform distortions of 5.5lambda and 18.

Use of concentrated human albumin with argon-beam coagulation in laparoscopic partial nephrectomy.

Purpose: Laparoscopic partial nephrectomy (LPN) remains a technically challenging procedure mainly because of the lack of reliable methods of hemostasis. We evaluated the feasibility of using concentrated human albumin with argon-beam coagulation to control hemorrhaging and urinary leakage during LPN.

Materials And Methods: Six domestic swine underwent heparinization, then lower-pole LPN after renal-hilar vascular control had been obtained.

Use of a chitosan-based hemostatic dressing in laparoscopic partial nephrectomy.

Objectives: An external chitosan-based hemostatic bandage has been used to control aggressive bleeding from traumatic injuries. This study was to evaluate the feasibility of using an internal chitosan dressing based on the external platform to control hemorrhage and urinary leakage by sealing off the parenchymal wound following Laparoscopic partial nephrectomy (LPN) in a porcine model.

Methods: Nine heparinized domestic swine underwent bilateral laparoscopic partial nephrectomies involving either a polar (N = 13) or wedge resection (N = 5) followed by treatment with the chitosan dressing.

Selective retina therapy (SRT): a review on methods, techniques, preclinical and first clinical results.

Selective retina therapy (SRT) is a new laser procedure for retinal diseases that are thought to be associated with a degradation of the retinal pigment epithelium (RPE). The aim of the irradiation is to selectively damage the RPE without affecting the neural retina, the photoreceptors and the choroid. Goal of the treatment is to stimulate RPE cell migration and proliferation into the irradiated areas in order to improve the metabolism at the diseased retinal sites.

Evaluation of the new photosensitizer Tookad (WST09) for photodynamic vessel occlusion of the choroidal tissue in rabbits.

Purpose: To determine the efficacy of Tookad (WST09; Negma-Lerads, Magny-Les-Hameaux, France) photodynamic therapy (T-PDT) by evaluating the angiographic and histologic closure of choroidal vessels at different radiance exposures, drug dosages, and intervals between photosensitizer injection and laser application in a rabbit model.

Methods: Chinchilla Bastard rabbits were injected intravenously with three different dye concentrations (2.5, 5, and 10 mg/kg) before application of light.

Different outcomes in urethral reconstruction using elastin and collagen patches and conduits in rabbits.

Objectives: To study the feasibility of urethral reconstruction with two urethroplasty techniques using an elastin and collagen heterograft in rabbits.

Materials And Methods: Fifty-two male rabbits were studied. Two types of injury, (1) a 1.

Preparation and characterization of polyurethane optical phantoms.

We describe a method for the preparation of a polyurethane phantom to simulate the optical properties of biologic tissues at two wavelengths in the visible and near-infrared spectral range. We characterize the addition of added molecular absorbers with relatively narrow absorption bands [full width at half maximum (FWHM) 32 and 76 nm for Epolight 6084 and 4148, respectively] for independent absorption at 690 nm for absorption up to 5 cm(-1), and 830 nm for absorptions up to 3 cm(-1). Absorption by both dyes is linear with concentration in these respective regions and is consistent in polyurethane both before and after curing.

Comparison of reduced and standard light application in photodynamic therapy of the eye in two rabbit models.

Background: Current PDT treatment for age-related macular degeneration uses a standard radiant exposure of 50 J/cm(2) at an irradiance of 600 mW/cm(2). However; there is a general problem with the unusually high irradiance; in fact, the rate of photochemical production of singlet oxygen may be limited by insufficiently oxygenized neovascular tissue. It was the aim of this study to evaluate the efficacy of verteporfin (Visudyne) photoactivation to induce thrombosis of choriocapillaries and in experimentally induced corneal neovascularizations in rabbits by varying irradiance and retinal radiant exposure.

Optoacoustic real-time dosimetry for selective retina treatment.

The selective retina treatment (SRT) targets retinal diseases associated with disorders in the retinal pigment epithelium (RPE). Due to the ophthalmoscopic invisibility of the laser-induced RPE effects, we investigate a noninvasive optoacoustic real-time dosimetry system. In vitro porcine RPE is irradiated with a Nd:YLF laser (527 nm, 1.

RPE damage thresholds and mechanisms for laser exposure in the microsecond-to-millisecond time regimen.

Purpose: The retinal pigment epithelium (RPE) cells with their strongly absorbant melanosomes form the highest light-absorbing layer of the retina. It is well known that laser-induced retinal damage is caused by thermal denaturation at pulse durations longer than milliseconds and by microbubble formation around the melanosomes at pulses shorter than microseconds. The purpose of this work was to determine the pulse width when both effects merge.

Temperature dependent fluorescence of A2-E, the main fluorescent lipofuscin component in the RPE.

Purpose: A2-E is the dominant fluorophore of lipofuscin in the retinal pigment epithelium. In an in-vitro setup, we determined the temperature-dependent changes of the A2-E fluorescence with the aim of also assessing the potential value of such measurements for determining retinal temperature by autofluorescence measurements during laser treatment.

Methods: A2-E was biosynthesized and diluted in Dimethyl Sulfoxide (DMSO) to 1 microM.

Design, testing, and clinical studies of a handheld polarized light camera.

Polarized light imaging has been used to detect the borders of skin cancer and facilitate assessment of cancer boundaries. A design for an inexpensive handheld polarized camera is presented and clinical images acquired with this prototype are shown. The camera is built with two universal serial bus (USB) color video cameras, a polarizing beamsplitter cube, and a 4x objective lens.

Laser-assisted vascular end to end anastomosis of elastin heterograft to carotid artery with an albumin stent: a preliminary in vivo study.

Background And Objectives: Laser-assisted end to end vascular anastomosis of an elastin heterograft to native artery may prevent problems associated with currently available vascular synthetic grafts and conventional suture anastomosis.

Study Design/materials And Methods: A total of 21 anastomoses in the carotid arteries of 7 domestic swine were performed with an 800 nm laser and an albumin stent plus solder. There were 5 artery to artery and 16 elastin heterograft to native artery anastomoses.

Concentrated albumin as a biological glue for hemorrhage control on hepatic resection with argon beam coagulation.

Topically applied concentrated albumin with argon beam coagulation (ABCA) has been shown to be more effective at achieving hemostasis than using argon beam coagulation alone (ABC) in a liver injury model. This study investigated the host response to the concentrated albumin after argon beam coagulation. Complete hemostasis was achieved using ABCA (N = 10) or ABC (N = 10) on a nonanatomic liver resection in a heparinized porcine model.

Laser-assisted end-to-end vascular anastomosis of elastin heterograft to carotid artery with an albumin stent in vivo.

Background Data: Laser-assisted end-to-end vascular anastomosis of an elastin heterograft to native artery may avoid the problems associated with currently available vascular synthetic grafts and conventional suture anastomosis.

Methods: A total of 21 anastomoses in the carotid arteries of seven domestic pigs were performed with an 800-nm laser and an albumin stent plus solder. There were five artery to artery and 16 elastin heterograft to native artery anastomoses.

Online autofluorescence measurements during selective RPE laser treatment.

Background: Fundus autofluorescence (AF) is derived from the lipofuscin contained by the retinal pigment epithelial cells. Using a scanning laser ophthalmoscope, two-dimensional AF measurements of the ocular fundus can be achieved. Directly after conventional photocoagulation and also after selective RPE laser treatment (SRT) with ophthalmoscopically non-visible laser lesions, irradiated areas reveal reduced AF, indicating RPE damage.

Optimal dye concentration and irradiance for laser-assisted vascular anastomosis.

Objective: This investigation was done in order to find optimal indocyanine green (ICG) concentration and energy irradiance in laser vascular welding.

Background Data: Many studies have shown that laser tissue welding with albumin solder/ICG may be an effective technique in surgical reconstruction. However, there are few reports regarding optimal laser settings and concentrations of ICG within the albumin solder in laser-assisted vascular anastomosis.

Biocompatibility of a xenogenic elastin-based biomaterial in a murine implantation model: the role of aluminum chloride pretreatment.

We have investigated the long-term effect of aluminum chloride (AlCl(3)) treatment on the calcification and inflammatory reaction of a porcine elastin-derived biomaterial (PEB) in a novel subdermal adult mouse model. Untreated PEB disks and PEB treated with AlCl(3) were implanted subdermally in BALB/c mice for 30, 60, and 180 days. The calcification of the elastin disks was examined with histological analysis and atomic absorption analysis of calcium content.

Noninvasive optoacoustic temperature determination at the fundus of the eye during laser irradiation.

In all fundus laser treatments of the eye, the temperature increase is not exactly known. In order to optimize treatments, an online temperature determination is preferable. We investigated a noninvasive optoacoustic method to monitor the fundus temperature during pulsed laser irradiation.