bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laser‐induced photoacoustic injury of skin: Effect of inertial confinement
Authors: Yashima Yutaka , McAuliffe Daniel J. , Jacques Steven L. , Flotte Thomas J. 
Published: March 2007

AbstractArgon‐fluoride (ArF) excimer laser‐induced acoustic injury was confirmed by ablating the stratum corneum (s.c.) inertially confined by water in vivo. Hairless rats were irradiated through a quartz chamber with flowing distilled water or air and a 2.5 mm aperture. The laser was adjusted to deliver 150 mJ/cm2 at the skin surface for both conditions. Partial and complete ablation of the s.c. was achieved with 12 and 24 pulses, respectively. Immediate damage was assessed by the transmission electron microscopy. Partial ablation of the s.c. through air produced no damage, whereas partial ablation through water damaged skin to a mean depth of 114.5 ± 8.8 μm (±SD). Full thickness ablation of the s.c. through air and water produced damage zones measuring 192.2 ± 16.2 and 293.0 ± 71.6 μm, respectively (P<0.05). The increased depth of damage in the presence of inertial confinement provided by the layer of water strongly supports a photoacoustic mechanism of damage. The damage induced by partial ablation of the s.c. provides evidence that photochemical injury is not a significant factor in the damage at a depth because the retained s.c. acts as a partial barrier to diffusion of photochemical products. Combined with our previous studies, these experiments demonstrate that pressure transients are responsible for the deep damage seen with 193 nm ablation and that photoacoustic effects must be considered when using short‐pulse, high‐peak power lasers.
Generation of “soft x‐rays” by using the free electron laser as a proposed means of diagnosing and treating breast cancer
Authors: Carroll Frank E. 
Published: March 2007

AbstractThe diagnosis and treatment of breast lesions may be markedly enhanced by the use of a unique new source of near‐monochromatic x‐rays.Concentric beams of near‐monochromatic x‐ray photons may be generated by collision of the free electron laser (FEL) electron beam with the optical beam in an interaction zone that delivers the x‐rays to a shirtsleeve environment.The absence of Compton scatter and the photoelectric interaction within tissues improves conspicuity of lesions by two to six times. Increased attenuation of x‐rays in malignant vs. normal tissues makes tumors more obvious. K‐edge subtraction allows chemical analysis of tumors in vivo—all at radiation doses that are one‐tenth to one‐fiftieth that delivered by the lowest‐dose mammographic x‐ray technique available. This allows for an increased sensitivity and specificity and permits prediction of histology, negating necessity for biopsies.Selective bond‐breaking at depth in tissues as well as x‐ray‐activated photodynamic therapy are also being explored.
Excimer‐laser‐induced fluorescence of rabbit cornea: Radiometric measurement through the cornea
Authors: Ediger M. N. 
Published: March 2007

AbstractThe laser‐induced fluorescence spectrum of rabbit cornea irradiated at ablative intensities was measured. This system directly measured the radiant exposure of fluorescence transmitted through the cornea when the anterior surface of the cornea was irradiated by an ArF excimer laser. Evidence of changing spectral characteristics as a function of total laser dose suggests photochemical changes in the cornea may be occurring. Results are compared with previous data of laser‐induced fluorescence in other models and detection schemes.
Autofluorescence of normal and malignant bronchial tissue
Authors: Hung Jaclyn , Lam Stephen , Leriche Jean C. , Palcic Branko 
Published: March 2007

AbstractIn vivo autofluorescence spectra were obtained in 5 patients with carcinoma in situ, 26 patients with invasive tumors, and 1 patient with severe dysplasia. Significant spectral differences were observed between pre‐cancerous, cancerous, and normal bronchial tissues. This difference may afford a method to image and/or detect early lung cancer by using tissue autofluorescence alone.
Photodynamic therapy of the canine peritoneum: Normal tissue response to intraperitoneal and intravenous photofrin followed by 630 nm light
Authors: Tochner Z. , Mitchell J. B. , Hoekstra H. J. , Smith P. , Deluca A. M. , Barnes M. , Harrington F. , Manyak M. , Russo D. , Russo A. 
Published: March 2007

AbstractA toxicity study was performed in a canine model to explore the feasibility of using intraperitoneal photodynamic therapy for patients with peritoneal carcinomatosis.Dogs received 1.25 mg/kg Photofrin II both intravenously (48 hours) and intraperitoneally (2 hours) before intraperitoneal light treatment. The entire peritoneal surface was illuminated with 0.57–0.74 J/cm2 of red light (630 nm). Thirteen dogs were treated 4 control and 9 full treatment. Of the fully treated dogs, 5 received a single treatment and 4 received 3 treatments. The dogs were evaluated clinically and pathologically for immediate (4 days) and late (60 days) side effects.All animals tolerated the treatment without significant morbidity. Postoperative blood tests were normal except for low lymphocyte counts and elevated liver transaminases, both of which normalized rapidly. Histopathologically, there was approximately a 50% incidence of mild inflammatory peritoneal response.This study provides the basis for a Phase I human trial.
Light dosimetry model for photodynamic therapy treatment planning
Authors: Grossweiner Leonard I. 
Published: March 2007

AbstractA light dosimetry model for photodynamic therapy is described leading to the dependence of necrosis depth on incident light dose. Semiempirical dosimetry relations are derived for four modes of light delivery. Results for Photofrin® II at 630 nm are summarized in graphical form. Numerical values of the parameters and necrosis depth calculations are compared with literature data.
Potential use of holmium lasers for angioplasty: Evaluation of a new solid‐state laser for ablation of atherosclerotic plaque
Authors: Haase Karl K. , Baumbach Andreas , Wehrmann Manfred , Duda Stefan , Cerullo Giulio , Rückle Benno , Steiger Erwin , Karsch Karl R. 
Published: March 2007

AbstractTissue effects of the mid‐IR Holmium laser (emitting at a wave‐length of 2130nm) were evaluated. This wavelength is attractive because it combines high water absorption and easy transmission through standard optical fibres. The laser was pulsed with pulse durations in the range of 100μsec and repetition rates between 2 and 6 Hertz. For all experiments a repetition rate of 2 Hertz was used. The laser beam was coupled into waterfree quartz fibers with core diameters of 200 and 800μm with an efficiency of 70 and 80%, respectively. Ablation of atherosclerotic plaque has been performed at an ablation threshold of 10J/cm2 for the 800μm and 40J/cm2 for the 200μm fibre. Removal of calcified plaque was possible. Ablation efficiency increased in a non‐linear fashion with increasing pulse energies. The ablation rate per pulse was approximately 2mm at energy fluences of 1000J/cm2 for the 200μm fibre and 1.25mm at energy fluences of 70J/cm2 for the 800μm fibre; a further increase in energy densities did not result in higher ablation rates. On macroscopic examination only very limited thermal injury was found in crater adjacent tissue structures. Crater edges were even and did not reveal signs of crater charring or debris in the crater lumen. However, the histologic specimens revealed zones of thermal damage extending 100 up to 1000μm lateral into adjacent tissue. Thermal damage increased with increasing radiant exposures and depended on the medium used.
Recanalization of arterial occlusions with a lensed fiber and a holmium:YAG laser
Authors: White Christopher J. , Ramee Stephen R. , Collins Tyrone J. , Mesa Juan E. , Paulsen Daniel B. , Murgo Joseph P. 
Published: March 2007

AbstractLaser recanalization of totally occluded swine iliac arteries was performed to assess the safety and efficacy of a lensed fiber laser angioplasty system with a holmium:YAG (2.1 μm) laser. Silica lenses of 1.0 mm, 1.3 mm, and 1.5 mm in diameter attached to the distal end of a 300‐μm diameter silica fiber delivered fluences of 79.5 J/cm2, 31.4 J/cm2, and 25.5 J/cm2, respectively. The pulse duration of the laser was 250 μsec and the repetition rate was 4 Hz. The mean length of the total occlusions was 5.3 ± 2.0 cm (range 0.5 cm to 8.0 cm). Successful recanalization was obtained in 16/16 lesions without angiographic vessel perforation. Angiographically significant residual stenoses (>50%)remained in every case following successful laser recanalization. Histologically there was minimal evidence of thermal or acoustic tissue injury; however, in 4 of 16 arteries there was evidence of deep arterial dissection following laser recanalization. We conclude that this lensed fiber coupled with a holmium:YAG laser is a safe and effective method for crossing total occlusions in the relatively straight iliac arteries of this animal model.
CW laser ablation velocities as a function of absorption in an experimental one‐dimensional tissue model
Authors: Gijsbers Geert H. M. , Selten Frank M. , van Gemert Martin J. C. 
Published: March 2007

AbstractOne‐dimensional continuous‐wave laser tissue ablation models predict that the steady‐state ablation velocity is independent of the optical absorption of the tissue and proportional to laser power density. This theoretical result was tested in an experimental model that approximates the one‐dimensional situation. The model consists of 3 to 4 mm‐diameter polyacrylamide rods irradiated at one end with an argon laser beam with uniform power density. It was found that ablation velocity is indeed independent of the light absorption coefficient in the material and proportional to the incident power density. Analysis of the relation between the experimental velocities and the power density showed that approximately 40% of the incident laser light is reflected or attenuated in the escaping vapors. Furthermore, compared to the actual absorbed laser power, heat loss caused by thermal radiation and convection from the side surface of the rod is considerable during ablation, especially at lower power densities. This heat loss is not present in a true one‐dimensional geometry and creates therefore marked difference between the rod and one‐dimensional geometry. Computations show that in the pre‐ablation stage the heat losses from the rod can be neglected, compared to the absorbed energy. In this case the rod is a very good approximation of the true one‐dimensional situation.
Operative laparoscopy with the Nd:YAG laser in the treatment of endometriosis and pelvic adhesions
Authors: Shirk Gerald J. , Brumsted John R. , Gimpelson Richard J. 
Published: March 2007

AbstractA multicenter, prospective trial was initiated to test the effectiveness and safety of the Nd:YAG laser equipped with artificial sapphire contact tips for the laparoscopic treatment of pelvic pain. Ninety‐three women were enrolled in the study, 37 with endometriosis alone, 47 with endometriosis complicated by pelvic adhesions, and 9 women with adhesions alone. In over 90% of adhesions and 96% of endometriotic implants the Nd:YAG laser could be delivered to the site and be used to restore normal anatomy. The exception was deep bowel involvement with endometriosis, which was not treated. The majority of women had marked reduction or resolution of their symptoms for up to 12 months postoperatively. We conclude that the use of the Nd:YAG laser is an appropriate method to laparoscopically treat pelvic pain resulting from endometriosis or pelvic adhesions.
Comparison of four laser types for experimental pain stimulation on oral mucosa and hairy skin
Authors: Svensson Peter , Bjerring Peter , Arendt‐Nielsen Lars , Nielsen Jens C. , Kaaber Svend 
Published: March 2007

AbstractThe use of different lasers for stimulation in human experimental pain research has provided a sensitive method for evaluation of thin nerve fiber functions. In this study, sensory and pain thresholds were compared to argon‐, copper vapour‐, Nd:YAG‐, and CO2 laser stimulation on hairy skin and on oral mucosa. The influence on thresholds with respect to laser type, stimulation site, surface colour, and stimulus parameters (laser beam diameter and pulse duration) was investigated. Significant differences in thresholds between the four lasers were found on both surfaces; however, no significant differences existed between thresholds on the skin and on the tongue when the same laser was used. The observations imply that wavelength‐dependent optical properties of the stimulated tissue influence on threshold determinations. Furthermore, the results indicate that temporal and spatial summation mechanisms may exist for laser induced warmth and pain perceptions. Laser stimulation may be a new tool for the investigation of origin and genesis of various orofacial pain syndromes.
Experimental treatment of thrombotic vascular occlusion
Authors: Labs Joseph D. , Caslowitz Pamela L. , White Robert I. , Anderson James H. , Melville Williams G. 
Published: March 2007

AbstractThe role of laser energy in the treatment of thrombotic vascular occlusion was evaluated in two sets of experiments. First, 10 polytetrafluoroethylene grafts were used to replace segments of the superficial femoral arteries in dogs and were thrombosed by distal ligation. Occlusion was maintained for one hour, or for 7, 14, 21, and 28 days in each of two grafts. Patency was restored in all 10 grafts without perforation or anastomotic disruption using a 2 mm hot tip probe powered by an Argon laser. However, increased organization of thrombus related to the duration of occlusion lead to decreased laser channel diameters, and 75% of the 28 day thrombus remained in the graft after recanalization.The second experiments tested the added benefit of thrombolytic infusion following laser recanalization. Bilateral external iliac artery thrombosis was induced in dogs by operative vessel isolation, de‐endothelialization, and thrombin injection. At 7 days the efficacy of laser‐assisted thrombolysis (LAT) versus enzymatic thrombolysis (ET) alone was compared. Eight vessels underwent ET by urokinase (4000 I. U./min.); 14 vessels were laser recanalized prior to thrombolytic infusion. LAT was performed from a carotid artery approach in 8 vessels (antegrade) and from a femoral artery in 6 vessels (retrograde). In contrast to studies using the hot tip alone, both ET and LAT accomplished complete thrombus removal. However, LAT lead to significant iliac arterial flow in 9 ± 8 min. (antegrade) and 25 ± 8 min. (retrograde) while ET required 109 ± 47 min (p < 0.01). Further, the rate of clot lysis during antegrade LAT was twice that of enzyme infusion without laser recanalization: 14.6 ± 6.2 vs 7.8 ± 1.1 mm3/min.(p < 0.01). LAT, therefore, achieved the treatment objectives: rapid, atraumatic, and complete removal of thrombus from the vasculature.
In vitro production of viable bacteriophage in carbon dioxide and argon laser plumes
Authors: Matchette Stephanie L. , Faaland Robert W. , Royston David D. , Ediger Marwood N. 
Published: March 2007

AbstractBoth CO2 and argon laser ablation of an agar substrate containing high titres of bacteriophage ϕX174 create plumes which disperse viable phage particles. Irradiances at the beam impact site ranged from 73 to 215 W/cm2 for the CO2 laser and from 40 to 227 W/cm2 for the argon laser. To increase the absorption of argon laser radiation, oxidized hemoglobin was added to the target material. Plume‐borne viable phage were observed to be associated with particles large enough to settle out from the plume within 100 mm of the beam impact site. The ratio of the number of dispersed viable phage to the number of viable phage potentially dispersible by a single, 1‐second laser exposure was on the order of 10−6 to 10−5.
Argon laser therapy for perianal Bowen's disease: A case report
Authors: Boynton Kathleen K. , Bjorkman David J. 
Published: March 2007

AbstractBowen's disease (intraepithelial squamous cell carcinoma) may occasionally occur in anal canal or perianal region. Surgical excision in this area may result in significant complications and a recurrence rate of 9–19%.A case of successful treatment of anal and perianal Bowen's disease using argon laser therapy is presented. No acute or chronic complications resulted from laser therapy. Twenty‐eight months after the initial diagnosis the patient is disease free. Laser therapy also provides the potential for repeated treatment of recurrent lesions without significant patient discomfort or inconvenience. Argon laser therapy should be considered as a therapeutic option in the treatment of Bowen's disease.
Water‐jet‐cooled Nd:YAG laser coagulation: Selective destruction of rat liver metastases
Authors: van Hillegersberg Richard , Kort Will J. , Ten Kate Fiebo J. W. , Terpstra Onno T. 
Published: March 2007

AbstractThe photocoagulating properties of the water‐jet‐cooled Nd:YAG laser (1,064 nm) have been studied in a rat tumor model. A colon carcinoma CC531 was implanted in the liver; 20 days after inoculation, laser therapy was performed with 600 J, 850 J, 1,200 J, 1,700 J, or 2,400 J at a power setting of either 10 or 20 W. Liver damage was determined in tissue specimen on day 1 after treatment and by serum levels of alanine aminotransferase and aspartate aminotransferase on day 1 and 2. Tissue specimen of day 36 were used to evaluate tumor remission. Liver function was assessed by antipyrine clearance on day 2. Light microscopic examination on day 1 showed coagulative necrosis up to 10 mm in diameter at 1,700 J and 20 W. At 20 W, liver damage was 22% larger than at 10 W (P = 0.0001). A significant relationship was found between laser energy and liver damage with complete tumor destruction in all animals at 2,400 J. No deterioration in liver function was found. The results of this study show the ability of the water‐jet‐cooled Nd:YAG laser to produce tumor coagulation necrosis with minor liver damage.
New laser delivery device for laparoscopic procedures
Authors: Bhatta Krishna M. , Rattner David W. , Haw Thomas E. , Nishioka Norman S. 
Published: March 2007

AbstractA new device to facilitate laser delivery and improve mechanical advantage during surgical procedures is described. In the device, a quartz fiber is used to transmit laser energy to a forked metal tip. The utility of the device was assessed in five pigs. In three pigs a laparoscopic cholecystectomy was performed and in two pigs a laparoscopic lymph node dissection was performed. Advantages of the device included reduced smoke, clearer dissection planes, tactile feedback, and excellent mechanical advantage when used for blunt dissection. The device was qualitatively superior to both sculpted tip quartz fibers and electrocautery.
In vivo canine coronary artery laser irradiation: Photodynamic therapy using dihematoporphyrin ether and 632 nm laser. A safety and dose‐response relationship study
Authors: Mackie R. William , Vincent G. Michael , Fox Jolene , Orme Eric C. , Hammond M. Elizabeth H. , Chang‐Zong Cui , Johnson Michael D. 
Published: March 2007

AbstractThis study examined the safety and dose‐response relationships of 632‐nm laser irradiation of photosensitized normal coronary arteries in 27 dogs. Fifteen received 2.5 mg/kg dihematoporphyrin ether (DHE), seven received no sensitizer, and five had coronary instrumentation but no laser (sham laser procedures) at nine coronary sites—four sensitized, five non‐sensitized. Laser energy of 82 to 1,640 J/cm2 was delivered via a 584 μm diffusingtip optical fiber, providing estimated tissue fluences of 20 to 410 J/cm2. Serial electrocardiograms and selective coronary arteriograms were performed up to 1 month post laser irradiation. Histologic examination was performed of all treated sites. Tissue fluences <200 J/cm2 produced no permanent electrocardiographic or angiographic changes; reversible spasm occurred in 2/8 photosensitized‐lased, 0/2 non‐photosensitized‐lased. Minor medial damage occurred in 1/8 sensitized‐lased, 1/2 non‐sensitized‐lased, and 0/9 sham‐lased sites.At tissue fluences >200 J/cm2 4/7 sensitized‐lased animals died prematurely—one due to immediate and irreversible coronary spasm and Q wave infarction, one due to fibrillation during 48‐hour follow‐up coronary angiography (normal angiograms), two with normal electrocardiograms and angiograms within one day of undetermined death; 0/5 non‐sensitized‐lased animals expired or had coronary spasm; and 3/7 sensitized‐lased and 0/5 non‐sensitized/lased had significant medial to adventitial histologic damage. Coronary irradiation at <200 J/cm2 appears to be safe for photodynamic treatment of atherosclerotic lesions. Pretreatment for coronary spasm is appropriate.
Temperature response of biological materials to pulsed non‐ablative CO2 laser irradiation
Authors: Brugmans Marco J. P. , Kemper Jim , Gijsbers Geert H. M. , van der Meulen Freerk W. , van Gemert Martin J. C. 
Published: March 2007

AbstractThis paper presents surface temperature responses of various tissue phantoms and in vitro and in vivo biological materials in air to non‐ablative pulsed CO2 laser irradiation, measured with a thermocamera. We studied cooling off behavior of the materials after a laser pulse, to come to an understanding of heat accumulation and related thermal damage during (super) pulsed CO2 laser irradiation. The experiments show a very slow decay of temperatures in the longer time regime. This behavior is well predicted by a simple model for one‐dimensional heat flow that considers the CO2 laser radiation as producing a heat flux on the material surface. The critical pulse repetition frequency for which temperature accumulation is sufficiently low is estimated at about 5 Hz. Although we have not investigated the ablative situation, our results suggest that very low pulse frequencies in microsurgical procedures may be recommended.
Histochemical evaluation of the coagulation depth after argon laser impact on a port‐wine stain
Authors: Neumann Reinhard A. , Knobler Robert M. , Leonhartsberger Helmut , Böhler‐Sommeregger Kornelia , Gebhart Walter 
Published: March 2007

AbstractA two‐step excisional treatment of a port‐wine stain (PWS) on the back of a 43‐yr‐old female patient was performed. Immediately before the first surgical treatment, two corresponding series of argon laser impacts were performed, each on one PWS half. Different laser parameters with irradiances ranging from 95 to 382 W/cm2 and energy fluences ranging from 19 to 114,6 J/cm2 were used. Laser spots on the first part to be excised were biopsied 10 min after laser treatment and prepared for histochemical analysis by staining with nitro blue tetrazolium chloride (NBTC). Reduction of this redox dye by nicotinamide adenine dinucleotide diaphorase (NADH‐diaphorase) leads on frozen tissue sections to an intense blue precipitate. The activity of NADH‐diaphorase subsides immediately upon cell damage. All vital epidermal and dermal cells presented a dense blue granular pigment in their cytoplasm, sparing the nuclei. Laser induced arc‐shaped epidermal and dermal necrosis did not stain, showing a clear demarcation from surrounding vital tissue. The depth of the thermal injury ranged from 0.28 to 0.45 mm; it did not correlate with the chosen fluences. With these penetration depths, the vast majority of PWS vessels was affected. Assessment of the remaining part of the PWS 8 months later yielded blanching of all laser‐treated areas. With the NBTC method, an accurate definition of laser‐induced tissue damage is feasible. It could be shown that the exposure time is the most relevant parameter influencing the penetration depth.