bluuebunny/crossref_metadata_2025 huggingface dataset:
Synovial Response to Laser Induced Carbon Ash Residue
Authors: Whipple Terry L. , Caspari Richard B. , Meyers John F.
Published: March 2007

Most surgical applications of CO2 laser energy permit carbonized and devitalized tissue to slough and become exteriorized through some natural orifice. The use of laser energy in joints with no external communication, however, must rely on synovial response to clear the carbon ash residue.

Sixteen New Zealand white rabbits underwent arthrotomy and subtotal laser meniscectomy with no effort to cleanse the carbon residue. The animals were sacrificed at regular intervals up to 8 weeks, and the menisci and synovium were harvested for microscopic inspection. The initial synovial response was characterized by hypertrophic changes with a moderate increase in cell population and subsynovial interstitial fluid. Particulate matter was invested by the synovium, and provoked an influx of acute inflammatory cells. By 6 weeks, only rare particles of carbonaceous material were found in the synovium and no particulate matter could be located by 8 weeks.

Laser induced carbon ash residue appears relatively innocuous to the joint in vivo and is readily cleared by an adequate and short‐lived synovial response.
Hematoporphyrin derivative and photoradiation therapy in early stage lung cancer
Authors: Hayata Yoshihiro , Kato Harubumi , Konaka Chimori , Ono Jutaro , Amemiya Ryuta , Kinoshita Komei , Sakai Harumasa , Yamada Ryuichi
Published: March 2007

Photoradiation therapy (PDT) with administration of hematoporphyrin derivative (HPD) was performed in ten cases of early stage central‐type lung cancer of which six cases were treated by PRT alone due to inoperability because of poor pulmonary function I five and refusal of surgery on one. Four cases were resected after PRT. In the former, complete tumor remission was seen in one and significant remission in three. In the nonresected cases four cases are disease‐free at 17–41 months and the remaining two cases died of chronic obstructive lung disease and cerebral infarction 16 and 31 months after surgery. Indications of PRT in early stage lung cancer are discussed according to histological findings of resected specimen.
Response of psoriasis to red laser light (630 nm) following systemic injection of hematoporphyrin derivative
Authors: Berns Michael W. , Coffey Joan , Wile Alan , Rettenmaier Mark , Berman Michael , Disaia Philip , Weinstein Gerald , McCullough Jerry
Published: March 2007

Systemically injected hematoporphyrin derivative (HPD) in combination with red laser light (630 nm) was used to treat a patient with intraepithelial neoplasia of the vulva. Since the patient had psoriasis in the mons pubis area this region also was exposed to the red light. The psoriasis treatment area was divided into two regions receiving 40 and 20 J/cm2. Both psoriatic zones responded vigorously to the HPD + light treatment, forming eschars by 1 week postirradiation. All there treatment zones (the neoplastic area and the two psoriatic areas) underwent normal reepithelialization by 17 days.
Exposure (dose) tables for hematoporphyrin derivative photoradiation therapy
Authors: Berns Michael W. , Berns Gregory S. , Coffey Joan , Wile Alan G.
Published: March 2007

Two sets of tables are presented that permit the rapid determination of (1) milliwatts per centimter2 based upon known site diameter and power output from fiber optic and (2) time of exposure (minutes and seconds) based upon known site diameter and power output from fiber optic.
Carbon dioxide laser surgery for cervical intraepithelial neoplasia
Authors: Wright V. C.
Published: March 2007

During 1977–1983, 787 consecutive referred cases of CIN were treated by vaporization of a dome‐shaped defect, by excision of a cylindrical specimen, or a combination of procedures where 48% were CIN III. Vaporization was used for 72% of CIN I, 76% of CIN II, and 64% of CIN III cases. Less than 15% of vaporization and all excision cases were done in hospital under anesthesia; 11% had delayed bleeding requiring attention (admission was required in 2%); 100% of CIN I, 96% of CIN II, and 96% of CIN III cases were cured. Persistent disease was diagnosed at the first (96%) or second (4%) visit. Subsequent treatment included laser and less than 1% hysterectomy. Overall cure for laser surgery was 99·5%. Sixty‐eight patients subsequently became pregnant; outcomes were normally distributed. Treatment success in related to adequate volume of tissue removed.
Hysteroscope for CO2 laser application
Authors: Tadir Y. , Raif J. , Dagan J. , Kaplan I. , Zuckerman Z. , Ovadia J.
Published: March 2007

Endoscopic laser surgery is becoming more common with the development of suitable instruments. A hysteroscope designed for use with a Sharplan CO2 laser is described in detail. The method of application, results of preliminary experience, and possible indications are discussed.
Treatment of condyloma acuminata with carbon dioxide laser: A prospective study
Authors: Scott Robert S. , Castro Dan J.
Published: March 2007

The common wart has been a ubiquitous problem throughout recorded history. In recent times, the genital wart has assumed more and more importance. These viral growths cause itching and burning as well as more severe problems. Treatment traditionally has included a large variety of preparations from nature. Subsequently, man‐made chemicals were used along with freezing, burning, and surgical excision. Because of the pain, bleeding, scarring, and high recurrence rate with these treatments, a study was instituted in 1978 to evaluate the advantages of the CO2 laser for treatment of this condition. Results have been excellent. far exceeding what we expected. Recurrence rate has been under 2%. The control group had the usual high rate of persistence and recurrence. Recent work pointing to a strong association between human papilloma virus (HPV) and cancer of the female genitals suggests an increasing need for early, vigorous, and more effective treatment of these lesions.
Safety measures in gynecological laser surgery
Authors: Lobraico Rocco V.
Published: March 2007

The advantages of the laser have been extolled in the literature but, in contrast, there is a paucity of infomation on the hazards involved in its surgical use. Recognition and prevention of risks is a mandatory requirement. The experience by encounter is described with counsel as to the prerequisite of taking precautionary measures prior to and during any operative procedure. Although safety features are incorporated in the equipment by the manufactuer, failure to peruse the operating manual has led to unnecessary errors in application and control. The operator and assisting personnel must be disciplined to concentrate on every use of the laser. Granting professionals surgical laser privileges with minimal training is an error in administration. A safety officer should be designated from the nursing or technician staff who will be responsible for knowing all the federal rules and regulations, setting up equipment, and constantly exercising safety surveillance during a laser surgical procedure.
Interception of lymphatic drainage by Nd: YAG laser irradiation in rat urinary bladder
Authors: Zimmermann I. , Stern J. , Frank F. , Keiditsch E. , Hofstetter A.
Published: March 2007

Lymphatic drainage can be demonstrated by colloidal indian ink injection. A small intramural indian ink spot in the bladder dome is separated from the rest of the rat urinary bladder by encircling transmural Neodymium‐YAG (Nd:YAG) laser irradiation. In untreated animals there is an ink flow via the lymphatic vessels to the regional lymph nodes within several hours. In treated animals, after laser irradiation, the indian ink remains in the bladder dome and a penetration of the irradiated area cannot be found by macroscopic and histologic examination. Indian ink will be found in the regional lymph nodes after the ninth day of absorption of the coagulation necrosis and recanalisation of the intercepted lymphatics. Evidence for the interception of the lymphatic drainage is demonstrated by the distinctly delayed ink flow and the injected ink's remaining in the irradiated area. From this, we conclude that Nd:YAG laser irradiation is especially suitable for tumor coagulation, since simultaneous interception of lymphatic drainage will inhibit the spreading of tumor cells.
Investigation of carcinogenic effects of in Vitro Argon and CO2 laser exposure of fibroblasts
Authors: Apfelberg David B. , Mittelman Harry , Chadi Benny , Maser Morton R. , Lash Harvey
Published: March 2007

Mouse heteroploid fibroblasts were grown nine future generations in vitro tissue culture. The cells were exposed to argon laser, CO2 laser, and x‐ray. Results of scoring for mangnant transformation foci were tabulated and compared. Lasers did not produce a significant malignant transformation. Clinical laser use is reviewed and histology as well as long‐term clinical experience confirms the safety of lasers.
Review of the treatment of port wine stains with the argon laser
Authors: Touquet V. L. R. , Carruth J. A. S.
Published: March 2007

The role of the argon laser for the treatment of port wine stain (PWS) is reviewed in relation to the Southampton regime, which is based on finding the minimal blanching power. Both the advantages and limitations of this form of treatment are discussed, stressing the importance of first obtaining a satisfactory test patch.
Present status of laser neurosurgery
Authors: Stellar Stanley
Published: March 2007

A three‐fold approach to the status of laser neurosurgery was taken: 1) Questionnaire to Program Directors for neurosurgery training in the United States and Canada; 2) an analysis of titles in the preliminary neurosurgery program of the Fifth International Congress of Neurosurgery; 3) A literature survey convering the last 3 years of publication. The results showed increasing interest in the use of lasers in neurosurgery, especially for neoplasmas in brain and spinal canal. The CO2 laser still dominates the field but Neodymium YAG is also finding wide use. The author comments on directions that laser neurosurgery may take in the future. Special emphasis is made on new applications combining advanced technologies, including CAT scanning, untrasonography, stereotaxic techniques, and computer control.
Laser workshops in neurological surgery
Authors: Brown J. T. , Cerullo Leonard J.
Published: March 2007

With the recent increased popularity of laser use in neurosurgery, there arises the question of the value and necessity of a “hands‐on” laser workshop in preparing the surgeon for clinical use of the instrument. To find an answer, a questionnaire was recently circulated to those who had participated in such a workshop.

Participants were asked whether they were actually using the laser clinically since attending the workshop and, if so, the type of laser they were using. Whether the course was influential in their decision to use a laser and whether they felt they could have used the instrument without such a course was also asked. In addition, the surgeons were asked how long it took them to become comfortable using the laser. The types of procedures, the percentage of operative cases and the mode (freehand or microlinked) in which the laser was used was also investigated. Finally, absolute indications for laser use in neurosurgery and methods to improve laser education were sought.

The answers were varied and interesting, but it is our conclusion that a “hands‐on” workshop is both a valuable and necessary means of preparing a neurosurgeon for clinical use of a laser, and participation in such a course should be encouraged.
Carbon dioxide laser in scalp tumor surgery
Authors: Sacchini V. , Lovo G. F. , Arioli N. , Nava M. , Bandieramonte G.
Published: March 2007

The widespread application of the CO2 laser in surgical treatment of tumor led us to verify its usefulness in selected cases of scalp tumor. Twelve selected patients underwent CO2 laser surgical excision plus vaporization of the wound base for infiltrating tumors during 1980–82.

All patients showed associated pathologies that interfered with the traditional surgical excision and with anesthesiological practices.

Our experience has confirmed the effectiveness of the laser technique under these conditions and with respect to subsequent plastic restoration.
Primary fluorescence of rat muscle after CO2 laser thermal injury
Authors: Giordano P. A. , Prosperi E. , Bottiroli G.
Published: March 2007

Observations are reported indicating that CO2 laser radiation induces the appearance of strong primary fluorescence in the tissues surrounding the incidence zone of the beam. The characteristics of this emission were studied by means of cytofluorometric techniques on rat muscles and compared with the fluorescence obtained by a heating procedure or by storage of tissue slices.

Laser‐induced primary fluorescence was found to be related to the thermal effect of CO2 laser radiation. Moreover, evidence is provided that the processes occurring during heating and those occurring during tissue decomposition most probably produce the same fluorescent products, albeit with different rates.

From the results obtained, it is suggested that primary fluorescence can be used as a marker of the damage suffered by the irradiated tissues.
Preliminary results of argon and carbon dioxide laser treatment of keloid scars
Authors: Apfelberg David B. , Maser Morton R. , Dds Harvey Lash , White David , Weston Jane
Published: March 2007

Argon and CO2 lasers have been used to treat 13 patients with well‐established keloid scars of the trunk or earlobe. Multiple‐bore‐hole argon technique and total excision with the CO2 laser were attempted. One patient with an earlobe keloid responded to treatment, all other patients had no improvement.

Argon and CO2 lasers have been used to treat 13 patients with well‐established keloid scars of the trunk or earlobe. Multiple‐bore‐hole argon technique and total excision with the CO2 laser were attempted. One patient with an earlobe keloid responded to treatment, all other patients had no improvement.
Biological effect of He‐Ne laser: Investigations on functional and micromorphological alterations of cell membranes, in vitro
Authors: Kubasova Tamara , Somosy Zoltán , Unk Péter , Kókai András , Kovács Lajos
Published: March 2007

A 1‐J/cm2 dose of single laser‐irradiation applied on primary human embryo fibroblast culture was not followed either by functional or micromorphological alterations of cell surfaces. This dose, however, applied four times with 24‐hour intervals changed the functional conditions as well as surface charges of cell membranes. As detection methods, radioactive glucosamine uptake, lectin, and cationized ferritin‐binding techniques were applied. At the same time, the scanning and transmission electron microscopy of laser‐irradiated cells did not reveal any micromorphological or ultrastructural alterations. The effect of a 5‐J/cm2dose did not differ from that of 1 J/cm2. It is suggested that laser radiation‐induced circumstances on cell surfaces can contribute to the strength of cell‐to‐cell contacts, i.e., to the stimulation of epithelization experienced in the clinical gynecol‐ ogic practice.
Hematoporphyrin derivative and laser photodynamical reaction in the diagnosis and treatment of malignant tumors
Authors: Song Shou‐Zhong , Li Jun‐Heng , Zou Jin , Shu Ming‐Yan , Zhao Fu‐Yun , Jin Mao‐Lin , Guo Zhong‐He
Published: March 2007

This paper reports the use of hematoporphyrin derivative (HpD) with laser activation in China for the diagnosis and treatment of various kinds of malignant neoplasms.

Fluorescence observation for diagnosis was performed for 170 tumors. One hundred and fifty‐one (88.8%) fluoresced visably upon excitation with either argon or He‐Cd laser light.

One hundred and thirty‐nine malignant tumors in 136 patients were treated by this method. The percentage of all tumors responding to treatment was 80.6%. Partial to complete response were obtained in 51.1 % of the tumors treated.

The advantages and disadvantages of this method are discussed. It was found effective in treating various kinds of neoplasms located at different anatomical sites.

The penetrating depth of the laser is shallow. This limits its effect and application. A search for new photosensitizing drugs and an increase in the penetrating depth of laser irradiation are urgent goals for further development of this technique.
Thermal effects of the Nd: YAG and carbon dioxide lasers on the central nervous system
Authors: Burke L. , Rovin R. A. , Cerullo L. J. , Brown J. T.
Published: March 2007

The use of laser is becoming commonplace in neurological surgery because of the potential for surgical precision with minimal surrounding trauma, improved hemostasis, freedom from electrical interference of evoked potentials recordings, and a variety of other benefits. Despite this enthusiasm, there are little significant data regarding various laser‐neural tissue interactions. Thermal transformation was studied using both carbon dioxide and Nd: YAG lasers on rat cerebral cortex. The Nd: YAG laser produced a significant quantity of heat which spread far beyond the boundaries of the histologically identified lesion. The thermal profile of the carbon dioxide laser on brain indicated minimal thermal spread change, even immediately adjacent to the physical edge of the lesion. Mechanisms and ramifications are discussed.
In situ monitoring of myocardial metabolism by laser fluorimetry: Relevance of a test of local ischemia
Authors: Renault Guy , Sinet Martine , Muffat‐Joly Martine , Cornillault Jean , Jacques Pocidalo Jean
Published: March 2007

We have developed a hypoxia test by local ischemia, to be performed with a special probe adapted to an in situ NADH laser fluorimeter. Local ischemia is produced by pressurization on the organ surface in an area of approximately 0.2 mm2.

In order to assess the method on open‐chest rat hearts (ten), we used the following protocol: local ischemia tests (three), global anoxia (100% N2 ventilation), superimposition of local ischemia to global anoxia, and local ischemia tests during the period just prior to death and immediately thereafter.

Three different responses were observed: large amplitude of compensated fluorescence (F0) increase, medium amplitude of F0 increase, and no F0 increase. These responses were related to the metabolic state prior to the test (States 3, 4, and 5 of Chance's nomenclature).

We have thus demonstrated the possibility of very rapidly determining the in situ NADH degree of reduction, without a destructive assay. Such a parameter may be of great relevance in heart surgery, as it might allow detection of potentially harmful situations, thereby enabling early and appropriate treatment.
The use of the Nd:YAG laser in urology
Authors: Stein Barry S. , Richard Kendall A.
Published: March 2007

The use of the neodymium:YAG (Nd:YAG) laser in urology is still in its infancy. To date, the most widely published application of this laser is in the treatment of bladder carcinoma. We have utilized the Nd:YAG laser in 23 treatments for superficial bladder tumors. The laser has both advantages and shortcomings, which are thoroughly addressed. In our hands the laser has been a safe instrument for the treatment of these lesions, although we do not recommend its use for tumors >3 cm. We have treated two patients with invasive disease one week prior to planned cystectomy. In one case, no residual tumor was found at cystectomy, while the second patient had viable tumor only in an untreated area. Two patients were successfully treated with the laser for intractable bladder bleeding, one each with primary and secondary bladder tumor.

Seven patients with condylomata acuminata were treated with laser therapy. All had excellent results without complication. One patient with urethral bleeding secondary to trauma was treated without success, while one patient with a urethral hemangioma was well treated with the Nd:YAG laser. Thus the Nd:YAG laser would appear to have a place in the urologic armamentarium, but whether it is cost‐effective for widespread use remains to be seen.
Laser surgery in enclosed spaces: A review
Authors: Macruz Radi , Ribeiro Márcio P. , Brum José Mauro G. , Pasqualucci Carlos Augusto , Mnitentag Jaime , Bozinis Dimitrios G. , Marques Euclydes , Jatene Adib Domingos , Décourt Luiz V. , Armelin Egas
Published: March 2007

We describe the results of experiments carried out in the arteries of dogs, rabbits, guinea pigs, and humans, normal or atheromatous, calcified, or not, with the application of the argon and CO2 laser, in vitro or in vivo, directly or indirectly. Similarly, we present the results of laser effects when radiation is delivered through a special catheter with the purpose of producing aortic insufficiency, opening pulmonary valvular stenosis, desobstructing carotid and coronary obstruction induced in dogs as well as atheromatous obstructions in human amputated legs. Arterial wall perforation was present in 50% of all cases. We suggest four options in order to diminish this adverse result: (1) the use of coherent optical bundles which will allow the proper guiding of the laser beam, (2) the construction of a special catheter for proper handling of the laser‐carrying fiber, (3) a combination of optical and computer programs which will aid to identify calcified regions, and (4) the use of dyes which will be strongly and selectively absorbed by the atheromas and which will thus allow their destruction at low laser powers.
Laser endarterectomy
Authors: Eugene John , McColgan Stephen J. , Hammer‐Wilson Marie , Berns Michael W.
Published: March 2007

Laser radiation can be applied directly at a diseased artery to dissect the plaque away from the media and perform an open endarterectomy. The appropriate cleavage plane within the media can be achieved with the laser beam for precise reconstruction of the artery. Laser endarterectomy offers a technique for the study of laser radiation upon arteriosclerosis and may become a new modification of a standard surgical technique.
Absence of distal emboli during in vivo laser recanalization
Authors: Case Robert B. , Choy Daniel S. J. , Dwyer Edward M. , Silvernail Paul J.
Published: March 2007

We used an argon laser to recanalize occluded arteries in vivo and to determine the extent of any particulate matter resulting from the procedure that might cause embolization.

Thrombosis was achieved by balloon de‐endothelialization and thrombin injection in 12 canine femoral or carotid arteries in six dogs. The resulting totally occlusive thrombi (2.5–8.5 cm in length) were laser treated in situ 2–29 days after formation, using laser tip power outputs of 0.8–3.4 W. The treated arterial segment was perfused before, during, and after the recanalization procedure with 1,000 ml of heparinized saline. All saline passing through the artery was collected and studied by filtration through 20‐μm pore filter paper; 50‐ml unfiltered aliquots were studied by automated, calibrated cell counting and microscopically after centrifugation and staining.

All vessels except one were completely recanalized. Filtration yielded a thin reddish, dust‐like residue. No large fragments were found in 11 of 12 effluents. The residue after centrifugation was almost entirely composed of erythrocytes plus one to four 20‐30‐μm strands of amorphous cellular material per high‐power field. Cell counting showed that 99.1% of the material in the effluents was smaller than 9.37 μm.

These results demonstrate the presence of some filterable debris following laser recanalization of intraarterial thrombi, but it probably lacks any physiologic significance. Further study of this effect of laser recanalization is needed.
Embolization and vessel wall perforation in argon laser recanalization
Authors: Choy Daniel S. J. , Stertzer Simon , Loubeau Jean‐Michel , Kesseler Howard , Quilici Phillipe , Rotterdam Heidrun , Meltzer Lon
Published: March 2007

The primary concerns in the development of a laser catheter for intravascular use are the potential hazards of vessel wall perforation and distal embolization. We present evidence, using technetium 99‐labeled thrombi in two rabbit aortas and one human cadaver coronary artery, that distal embolization does not occur after argon laser recanalization. Also, no vessel wall perforation was observed during recanalization of 15 thrombosed rabbit aortas and 1 inferior vena cava, used because of their extremely thin walls. Laser recanalization of three peripheral arteries with atherosclerotic plaque obstruction, in amputated human legs, snowed no evidence of vessel wall perforation.

The incidence of vessel wall perforation can be minimized by preferential use of the argon laser, strict maintainence of a coaxial relationship between the laser catheter and the vessel, and exercising care during the actual lasing process.

Distal embolization does not appear to be an important consideration.
Responses of atherosclerotic aorta to argon laser
Authors: Dries David J. , Lawrence Peter F. , Syverud John , Moatamed Farhad , Dixon John
Published: March 2007

Lasers have been advocated to resect atherosclerotic plaques in the cardiovascular system, yet little information is available regarding the effects of laser on the range of occlusive lesions seen in the peripheral arterial tree. This study was conducted to assess the risk of perforation in human cadaveric aorta involved with variable degrees of atherosclerosis. Ten fresh segments of atherosclerotic human aorta were graded for extent of atherosclerosis, then subjected to argon laser energy within 48 hours. Using air as the conduction medium and with the fiber tip 2 or 5 mm from the vessel wall, the argon laser was applied to matched calcified and non‐calcified arteries at 3.0‐7.0 W and 10.0–13.5 W with energy density identical for matched pairs. Results were compared among segments which were normal in appearance or had only fatty streaks grossly with those with gross regional wall calcification. The mean penetration time (T) for calcified and non‐calcified lesions at low and high power outputs was compared. magnified image

Mean time to perforation and range of time necessary to produce perforation were greater in calcified than non‐calcified segments at all power levels employed. These data suggest that atherosclerotic lesions vary in their response to argon laser. The presence of calcium may preclude resection of some plaques and protect against wall perforation.
The use of the Nd‐YAG laser in neurosurgery
Authors: Beck O. J. , Frank F.
Published: March 2007

Whereas the focused CO2 laser may be used as a cutting instrument in less vascularized tissue with limited trauma to the surrounding tissue, use of the defocused Nd‐YAG laser results in homogeneous coagulation with an energy‐dependent depth effect. Thus, residual tumor tissue may be cauterized selectively with a depth effect which can be predicted with satisfactory precision. Tumor shrinkage and demarcation based on different absorption properties facilitates dissection and, moreover, allows the preservation of healthy tissue. The excellent coagulating properties of the Nd‐YAG laser render it especially effective in cases of highly vascularized meningeal tumors.
Microendoscopic surgery of the hypopharyngeal pouch with the CO2 laser
Authors: Hoeksema P. E. , Edens E.Th. , Van Overbeek J.J.M.
Published: March 2007

In 1964 we started to treat hypopharyngeal (Zenker's) diverticula endoscopically, using the procedure described by Dohlman. With the increase in the number of patients (350), the technique and the instruments used have improved. This paper describes the technique, which involves exposure of the tissue bridge between esophagus and diverticulum with the aid of a specially designed scope and subsequent severance with the CO2 laser of this bridge under microscopic control. The use of an operating microscope and the laser is a great improvement in endoscopic treatment of hypopharyngeal diverticula.
Nd‐YAG laser for general surgery
Authors: Iwasaki Masaru , Sasako Mitsuru , Konishi Toshiro , Maruyama Yuji , Wada Tatsuo
Published: March 2007

We report here our clinical experiences with Nd‐YAG laser on general surgery, and evaluate the results of this procedure. From December 1979 to December 1981, we applied Nd‐YAG laser to various operations as a hemostatic and cutting tool. For hemostasis, we used conventional quartz fiber which was covered with sterile tube, and hemostatic efficacy was examined especially in the subcutaneous bleeding and the bleeding from solid organs. For cutting, we used special devices, ie, Medilas YAG surgical probe (noncontact‐type probe), and a laser blade (contact‐type probe), and performed four liver resections. It is concluded that the hemostatic efficacy of Nd‐YAG laser to various bleeders was proved in general surgical procedures, and furthermore this laser can cut tissue if we utilize these devices. When comparing these two devices, we would prefer the contact‐type probe.
Preliminary investigative studies with PDT in dermatologic and plastic surgery
Authors: Goldman Leon , Gregory Richard O. , Plant Mary La
Published: March 2007

PDT has been shown to be of value in inoperable basal and squamous skin cancers and in cutaneous metastases. Azone, a new investigative vehicle for HpD, is of value more for intralesional injections than for topical applications in tumors, except perhaps for superficial mucous membrane lesions. The more flexible gold head vapor is of definite value in the PDT program.

For test models for PDT studies in dermatology and plastic surgery with HpD and other fluorochromes, single thickened resistant plaques of psoriasis and the common baso squamous acanthoma (seborrheic warty growth) have been used. In all these studies, adequate controls are necessary.
Investigating the CO2 laser for plantar digital neurectomy in horses
Authors: Montgomery Tom C. , McNaughton Scott D.
Published: March 2007

A histological study of plantar digital nerve sections cut with a carbon dioxide laser in horses was conducted. A series of nerve cuts were made with variable power densities to determine the appropriate theoretical level which would yield the most desired tissue effects. Power densities in the lower ranges used appeared to provide tissue effects judged most likely to prevent neuroma formation through increased thermal sealing of the proximal stump at the axon level. Clinical observation and follow‐up of horses subjected to laser neurectomy tend to support the reported concept that the laser is superior to conventional instruments for prevention of painful neuroma in peripheral nerves.
An accurate laser radiometer for determining visible exposure times
Authors: Royston David D.
Published: March 2007

A laser light radiometer has been developed for the Electro‐Optics Branch of the Center for Devices and Radiological Health (CDRH). The radiometer measures direct laser radiation emitted in the visible spectrum. Based upon this measurement, the instrument's microprocessor automatically determines at what time duration the exposure to the measured laser radiation would exceed either the class I accessible emission limits of the Federal Performance Standard for laser products or the maximum permissible exposure limits of laser user safety standards. The instrument also features automatic background level compensation, pulse measurement capability, and self‐diagnosis. Measurement of forward surface illumination levels preceding HpD photoradiation therapy is possible.
Effects of varying intensities of laser energy on articular cartilage: A preliminary study
Authors: Schultz Robert J. , Krishnamurthy Shanker , Thelmo William , Rodriguez Jose E. , Harvey Gregory
Published: March 2007

The effects of laser energy on articular cartilage were studied utilizing the neo‐dymium YAG laser. Partial‐thickness cartilage defects were surgically attempted in the femoral condyles of knee joints in guinea pigs. The defects were exposed to laser energy of varying intensities [group I, 25 J (5 W × 5 sec); group II, 75 J (15 W × 5 sec); group III, 125 J (25 W × 5 sec)]. A fourth group was studied, in which the defect was not lased. Animals were killed at weekly intervals from 1 to 6 weeks and the knee joints were subjected to histological analysis. At 5 weeks, the knees exposed to 25 and 75 J demonstrated a reparative process with chondral proliferation. The knees exposed to 125 J demonstrated fibrotic tissue and tissue necrosis that resulted in fibrosis. In the knees not exposed to laser energy, numerous foci of granulation tissue were present at all stages with the end point of healing being one of fibrosis with disorganized patchy cartilage islands.
The CO2 laser as an ideal microsurgical tool
Authors: Ohshiro Toshio
Published: March 2007

The CO2 laser was used as a multipurpose microsurgical tool. It effectively evacuated cysts, vaporized tumors, coagulated fine blood vessels, abraded and flattened scars and rough tissue, and separated the epidermis from the dermis. Focused and defocused modes were applied to various lesions ranging from cysts to freckles. CO2 laser microsurgery differs from previous methods in that extremely fine and controlled therapy can be conducted with minimal damage to surrounding tissues and organs. Theories, techniques, and several case reports are described.
The “chemo‐laser” technique for the treatment of decorative tattoos: A more complete dye‐removal procedure
Authors: Dismukes Don E.
Published: March 2007

A technique embodying the use of chemical agents and the argon laser was developed in the 1981–1982 that provides for a more complete removal of tattoo dye with one treatment. The number of visits for the laser treatment to the patient is reduced to two or three treatment sessions, compared to five to eight visits previously required. The area of “chemo‐laser” approximated the normal skin without hypertrophk scar tissue more than the areas of multiple or heavy laser treatment.
Tunable dye laser (577 nm) treatment of port wine stains
Authors: Morelli J.G. , Tan O.T. , Margolis R. , Seki Y. , Boll J. , Carney J.M. , Anderson R.R. , Parrish J.A. , Furumoto H. , Garden J.
Published: March 2007

Despite steady improvement in the laser treatment of port wine stains (PWS), hypertrophic scarring remains a serious side‐effect in approximately 10% of patients. The tunable dye laser (577 nm) has been shown to cause selective vascular destruction in normal and PWS skin. We have treated ten patients using a tunable dye laser (577 nm, 300 m̈sec) resulting in clearing of the PWS without any evidence of hypertrophic scarring.

Treatment requires no anesthesia or wound care, and there were no postoperative infections.
Bursting pressures of CO2 laser‐welded rabbit lleum
Authors: Sauer Jude S. , Rogers David W. , Raymond Hinshaw J.
Published: March 2007

In this study, the short‐term bond strength of laser‐welded New Zealand white rabbit ileum was examined. Forty‐eight longitudinally oriented 0.5‐cm transmural, scalpel incisions were reanastomosed solely through the use of the CO2 continuous wave laser at low energy levels. Random power levels of 250, 500, 750, or 1,000 mW were delivered to weld sites by either continuous application for 30 seconds or a pulsating application (ie, 0.5 seconds on, 0.5 seconds off) for 60 seconds. This provided 53.6, 107.1, 160.7, and 214.3 J/cm2, respectively. With the aid of a plexiglass clamp and pressure monitored infusion system, each type of weld was tested six times to determine the intraluminal hydrostatic pressure required to burst the welded seam 1 minute after completing the weld. For the welds made with 107.1, 160.7, and 214.3 J/cm2 in both lasing modes, the mean bursting pressure was 40.7 mmHg (SD ± 24.9) with no statistically significant difference in weld strengths at these energy densities. There was also no difference between continuous and pulsating delivery methods. However, the energy density of 53.6 J/cm2 in either method produced a mean bursting pressure significantly lower than those produced by the higher energy densities tested and below the estimated basal ileal intraluminal pressure of approximately 9 mmHg. Since 107.1 J/cm2 energy density caused the minimal gross tissue changes while producing an equally strong bond and since continuous is faster than pulsating, 500 mW of continuous delivery was considered the optimal setting for the CO2 laser welding of rabbit ileum.
Study of the in vivo and in vitro photosensitizing capabilities of uroporphyrin I compared to photofrin II
Authors: Stuart Nelson J. , Sun Chung‐Ho C. , Berns Michael W.
Published: March 2007

The in vivo biological activity of uroporphyrin I has been studied by determining the amount of necrosis produced in murine tumors exposed to various total doses of light at 615 nm. Similarly, the in vitro photosensitizing activity of uroporphyrin I was examined by measuring the percentage of cells killed in a cell culture system.

Light doses used were 25–400 J/cm2. Mice that received uroporphyrin I at 40 mg/kg had only minimal superficial necrosis upon histological examination at doses of 400 J/cm2 (615 nm). Those tumors that received 300 J/cm2 or less showed no histological evidence of necrosis. Mice that received hematoporphyrin derivative (Photofrin II) at 10 mg/kg were completely necrotic at total doses of 100 J/cm2 (630 nm). PTK2 epithelial cells incubated with uroporphyrin I at either 40 μg/ml or 80 μ/ml and 10 J/cm2 (615 nm) showed no apparent damage and had 100% cell survival. By contrast, those cells treated with hematoporphyrin derivative (Photofrin II) at 25 μ/ml and 10 J/cm2 (630 nm) exhibited 100% cell kill.

It is concluded that uroporphyrin I is a poor photosensitizer in both in vivo and in vitro systems compared to hematoporphyrin derivative (Photofrin II).
Cylindrical irradiator fiber tip for photodynamic therapy
Authors: Arnfield M. , Gonzalez S. , Mcphee M. , Tulip J. , Lea P.
Published: March 2007

In photodynamic therapy (PDT) the uniform distribution of intratumor or externally applied light is desirable but often difficult to achieve. An optical fiber tip producing cylindrical or lateral light emission can facilitate the application of laser energy by direct implantation of the tip into solid tumors or within tubular cavities of the body such as the bronchus or esophagus. A procedure is described for fabricating such a fiber tip, the main component of which is a hollow glass cylinder containing a light‐scattering material. Light distributions emitted from the tip in air are documented. Useful properties of the tip include good light distribution, durability, heat resistance, and simplicity of construction.
Contact neodymium: YAG laser surgery in gastroenterology: A preliminary report
Authors: Joffe Stephen N.
Published: March 2007

Fifty‐four patients have been successfully endoscopically treated without complications using contact neodymium:YAG laser probes (endoprobes) for tumors and bleeding and, during open surgery (laser scalpel), for liver and pancreatic resections. The contact probes made from a synthetic sapphire crystal with its optical properties, geometric design, and thermal conductivity have proven to be more effective than the current conventional noncontact method of delivering laser energy through a quartz fiber. Advantages include greater precision, sterilizability, avoidance of the tip melting, and a requirement for lower neodymium: YAG laser energy with reduced tissue damage. The configuration of the probes allows coagulation, cutting, or vaporization, depending on the clinical condition being treated.
Urologic dosimetry studies with the Nd: YAG and CO2 lasers: Bladder and kidney
Authors: Stein Barry S.
Published: March 2007

Dose recommendations for the use of the Nd: YAG and CO2 lasers have been accepted with little laboratory analysis. We have examined both endoscopic and open applications in the bladder and open applications on the kidney with the lasers over a variety of power and pulse duration settings. In addition, we have studied the effect of varying the temperature of the tissue and irrigation solution on the depth of penetration.

We found that with the Nd: YAG laser, the maximum depth of penetration in our animal model was only 2.62 mm in the bladder. This occurred during an endoscopic treatment with settings of 50 W at 4 seconds with irrigation solution of 25°C. The depth of penetration using current recommendations of 40 W for 2 seconds was<1 mm at all temperatures. Room temperature irrigation solution may be the ideal compromise, but higher‐power long‐pulse durations or repeated treatments to the same area may be necessary to achieve penetrations of 3–5 mm. In open applications on bladder and kidney, the maximum depth of penetration in our animal model was 2.75 mm, which was found during a treatment with settings of 60 W at 4 seconds with the kidney parenchyma at 25°C.

Using the CO2 laser on open applications of bladder strips, we obtained a maximum depth of penetration of 1.75 mm at 30 W of power for 1/2 second at 85°C tissue temperature. Unfortunately, penetration by the CO2 laser is accompanied by vaporization of tissue, leaving a large crater. Minimal injury exists beyond this area. In the kidney, we obtained a maximum depth of penetration of 1.75 mm at 30 W of power at 25°C and 20 W of power at 2°C each for 1/2 second.
Optical dosimetry in photodynamic therapy
Authors: Grossweiner Leonard I.
Published: March 2007

The diffusion approximation for the radiant flux distribution in a tissue layer has been applied to optical dosimetry in photodynamic therapy of malignant tumors. The model assumes that tumor eradication requires a minimum absorbed energy by the localized photosensitizer, taken as 0.19 J/cm3 for hematoporphyrin derivative (HPD) at 630 run. The analysis leads to the required incident irradiance for front surface illumination as a function of the tumor depth, the optical penetration depth of the tumor, and the concentration of localized sensitizer. The effect of HPD photobleaching on the required light dose and drug dose levels is considered. The results are given in tabular form for typical clinical applications.
Milliwatt carbon dioxide laser and hepatic surgery in mice: Surgical technique and pathology
Authors: Rao Leela N. , Ammirati Mario , Murthy Satya M. , Goldschmidt Robert A. , Ciric Ivan S. , Scanlon Edward F.
Published: March 2007

The milliwatt carbon dioxide laser was used to induce focal lesions and to perform wedge resections in the livers of 75 strain A mice. The procedures were feasible and well tolerated by the mice, with only one postoperative death in the wedge resection group in an early experiment. The hepatic lesions produced by the laser were characterized histologically by an inner area of vaporization, an intermediate area of coagulation necrosis, and an outer rim of cells with variable damage. The lesions healed by fibroblastic proliferation and scar formation with no hepatocytic contribution. The small vessel and bile ductule sealing effect of CO2 laser, together with the sound healing of laser‐induced wounds, highlights the usefulness of this modality in liver surgery in general, and suggests its particular application in the treatment of liver trauma and a variety of hepatic focal lesions, neoplastic or otherwise.
Modeling optical and thermal distributions in tissue during laser irradiation
Authors: Jacques Steven L. , Prahl Scott A.
Published: March 2007

The propagation of light energy in tissues is an important problem in phototherapy, especially with the increased use of lasers as light sources. Often a slight difference in delivered energy separates a useless, efficacious, or disastrous treatment. Methods are presented for experimental characterization of the optical properties of a tissue and computational prediction of the distribution of light energy within a tissue. A standard integrating sphere spectrophototneter measured the total transmission, Tt, total reflectance, Rt, and the on‐axis transmission, Ta, for incident collimated light that propagated through the dermis of albino mouse skin, over the visible spectrum. The diffusion approximation solution to the one‐dimensional (1‐D) optical transport equation computed the expected Tt, and Rt, for different combinations of absorbance, k, scattering, s, and anisotropy, g, and by iterative comparison of the measured and computed Tt, and Rt, values converged to the intrinsic tissue parameters. For example, mouse dermis presented optical parameters of 2.8 cm−1, 239 cm−1, and 0.74 for k,s, and g, respectively, at 488 nm wavelength. These values were used in the model to simulate the optical propagation of the 488‐nm line of an argon laser through mouse skin in vivo. A 1‐D Green's function thermal diffusion model computed the temperature distribution within the tissue at different times during laser irradiation. In vitro experiments showed that the threshold temperature range for coagulation was 60°–70° C, and the kinetics were first order, with a temperature‐dependent rate constant that obeyed an Arrhenius relation (molar entropy 276 cal/mol‐°K, molar enthalpy 102 kcal/mol). The model simulation agreed with the corresponding in vivo experiment that a 2‐s pulse at 55 W/cm2 irradiance will achieve coagulation of the skin.
Ultraviolet laser ablation of skin: Healing studies and a thermal model
Authors: Lane R. J. , Wynne J. J. , Geronemus R. G.
Published: March 2007

We have followed the course of healing of incisions made with the krypton‐fluoride excimer laser. Incisions were made in guinea pig skin, in vivo, under identical conditions of irradiation. The progressive healing of these incisions was followed over the course of 3 weeks. We noted excellent healing with re‐epithelialization, and the re‐formation of collagen fibers with minimal fibrosis. We present a simple thermal model for ablation of tissue by a short pulse of strongly absorbed laser radiation.
The influence of mechanical forces and flow mechanisms on vessel occlusion
Authors: Fankhauser F. , Kwasniewska S. , Bebie H.
Published: March 2007

The exact mechanism of irradiation‐induced occlusion of normal or abnormal retinal vessels is still to a large extent obscure. Blood flow acts as a powerful heat dissipation mechanism. Therefore, a procedure which reduces flow velocity as rapidly as possible after the beginning of irradiation may work with higher efficiency. A theory based on a simplified assumption states that vessel narrowing techniques, which involve only a short length of the vessel to be occluded by a small focus diameter irradiation beam, are less efficient in bringing blood velocity down than a procedure which narrows the vessel over a greater length by a larger focus diameter irradiation beam.

The thrombus building up over a greater length of the affected part of the vessel may also better resist the pressure head building up after thrombogenesis is complete because friction between thrombus and vessel wall is larger, and occlusion may, therefore, be more durable. One has to assess, therefore, whether a small‐spot technique, which is presumed to be less efficient and may need repetitions, is in fact less innocuous for the surrounding retina—as is generally assumed—than a technique using a larger beam diameter, which, because it is more efficient, may need fewer or even no repetitions.
Mechanisms of healing in the injured lung treated with the Nd‐YAG laser
Authors: Cole Peter H. , Wolfe Walter G.
Published: March 2007

An experimental study was done to evaluate the pattern of healing after sealing an incision in the pulmonary parenchyma with the Nd‐YAG laser. Gross and histologic examinations of healing were compared with those of lung cauterized or sutured with chromic catgut. The results indicate that the use of the Nd‐YAG laser to seal small vessels and air leaks has distinct advantages over cautery or suture closure of incisions in pulmonary tissue.