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The first laser employment for the treatment of the cervico-urethral obstructions (CUO) dates back to the early '90s. This study begins with the analysis of laser basics in Medicine and has the purpose to weigh pros and cons (and limits as well) of laser use in CUO due to Benign Prostatic Hyperplasia (BPH). That is an ageing man's typical disease and there is a huge need of minimally invasive treatments, because people affected by this kind of illness suffer very often from comorbidities, and that could make traditional surgery quite risky.The target of this study is the in vivo experimentation of a brand new laser diode, crated to be specifically used in BPH, and to verify its efficacy and safety.The subject of the study is the whole laser diode supply, with its double-band laser source (980 nm + 1470 nm), which gains a 140 W-power and is equipped with Water-Free optical fibers of different kinds of tip. We have tested a conical tip fiber on a standard 24-26 F-resectoscope instead of a standard diathermic loop. The conic fiber optimizes the energy on the treated tissue. We recruited 14 patients with CUO caused by BPH, 56 to 70 years old, with a prostatic volume between 33 and 53 cc, and we treated them with laser surgery using the power of 100-110 W. We considered the operative time, the intra-surgery complications and the specific side effects such as hematuria, pain, catheter removal time and the presence or not of acute urinary retention, in order to evaluate the efficacy and safety of this new technique.The possibility of using the same resectoscope as the one used in transurethral resection of prostate (TURP) made everything more comfortable and easy because of the immediate feeling with the new instrument and the actual time of Light Vaporization between 30 and 40 minutes, which is more or less the same time of a standard TURP procedure.The idea of a double-band-emitting laser used with conical tip fibers appears to be a great solution in the BPH treatment: it uses the principle of low power density plasma in order to treat bigger prostatic tissue areas but never going in depth. In our clinical results, the efficacy of the double-band-emitting laser source (1470 nm + 980 nm) appears to be similar, but even potentially greater, to the actual surgical laser options (such as HoLEP with Ho:YAG laser and PVP with KTP laser), and it is also similar to traditional TURP.

According to the "vascular" theory, arterial overflow in the superior hemorrhoidal arteries would lead to dilatation of the hemorrhoidal venous plexus. A 980-nm diode laser-pulsed shot causes shrinkage of tissue. The depth of shrinkage can be regulated by the power and duration of the laser beam. Through a 1000-micron conic fiber, five laser shots generated at a power of 13 W with duration of 1.2 s each and a pause of 0.6 s caused shrinkage of tissues to the depth of approximately 5 mm. Terminal branches of the superior hemorrhoidal artery in the anal canal, if precisely identified through a Doppler signal, can be closed with the use of this laser.A specially designed proctoscope has a small window that allows introducing a Doppler probe whose function is to identify hemorrhoidal arteries. Approximately 3 cm above the dentate line, the terminal branches of the superior hemorrhoidal artery (usually 8-12) are recognized through a clockwise rotation of the proctoscope and progressively fulgurated through a laser optic fiber. The procedure does not require anesthesia and can be performed as an ambulatory treatment.Thirty patients (16 men) with second to third grade symptomatic hemorrhoids have been treated with the described technique. The procedure proved to be successful at 3 months' follow-up in 92% of cases. No major adverse effects or complications were reported. Bleeding was observed in four cases. In two cases surgical hemostasis was necessary. Minor pain that required medication was reported in three cases.The hemorrhoidal laser procedure (HeLP) represents a new nonexcisional, mini-invasive treatment for patients suffering from second and third degree hemorrhoids without severe mucosal prolapse. Thermal occlusion of the hemorrhoidal arteries causes a progressive shrinkage of hemorrhoidal cushions. The procedure does not require anesthesia, is technically easy, repeatable, and can be performed as an office treatment.

A diode laser with roughly 480 mW/cm2 emission at 776 nm was developed and engineered to obtain a uniform illumination of tumour cells deposited on Petri dishes having an external diameter of 5 cm. The efficacy of the apparatus in inducing photocytotoxic effects was successfully checked by irradiation of pigmented melanoma cells in the presence of a photosensitizer, Si(IV)-naphthalocyanine, having intense absorption bands at 776 nm. Our results open interesting prospects for extending photodynamic therapy to highly pigmented tumours.

In the first part of our experience approximately 300 stones of different composition have been treated in vitro with three different laser sources: Nd-YAG laser (1,064 nm), dye laser (504 nm) and alexandrite laser (755 nm). Calcium oxalate monohydrate and brushite stones appeared to be the most resistant to lithotripsy. Highest fragmentation rates were obtained for calcium oxalate dihydrate stones followed by struvite, uric acid and hydroxyapatite stones. The Nd-YAG laser did not appear to be ideal for lithotripsy since early damage to the fiber tip was observed when this source was used. Both the dye and the alexandrite lasers were almost always effective in fragmenting the various types of stones. We subsequently treated some cystine stones while immersed in water or in solutions of carmine indigo (2%), methylene blue (5%), rifamycin (0.6 and 6%) and rifampicin (0.8 and 0.3%) with the dye or the alexandrite laser. The spectra of these solutions, previously analyzed with the spectrophotometer, showed that rifamycin and rifampicin absorbed large amounts of light radiation at the wave length of the dye laser (504 nm). Successful fragmentation occurred only when the dye laser was used to treat stones immersed in the more concentrated solutions of these two substances. The quantity of fragmented material after treating a 10-cm3 cystine stone previously immersed in the more concentrated solutions of rifamycin and rifampicin (30 and 10 mm3, respectively) confirmed previous results.(ABSTRACT TRUNCATED AT 250 WORDS)

In the last years, laser has gained increasingly high popularity in Endourology. The newer generation Ho-YAG lasers represent the most updated laser used in Urology, being able to successfully treat both urinary stones and soft tissue lesions. The aim of this work was to report a multicentre 4-year experience using the Ho-YAG laser in the treatment of stones and soft tissue lesions, in order to offer parameters and modalities of use in several different situations. MATERIALS AND METHODS. Two urological Centers were asked between 2002 and 2005 to use Coherent Versa Pulse 20 Ho-YAG laser source in the treatment of urinary stones in 212 patients, and urinary soft tissue lesions (urethra, ureter or bladder neck strictures or urinary tract tumors) in 56 patients. According to the various situations (either stone fragmentation or treatment of soft tissue lesions), pulse frequency and energy per impulse were differently dosed and set. RESULTS. The following parameters were identified as the starting points for the correct use of the Ho-YAG laser: a) lithotripsy with rigid endoscope: 365 μm fiber, 0.8 - 1.2 Joule (J) energy and 6-8 Hz frequency; 365 μm fiber, 0.8-1.2 J energy and 10-12 Hz frequency; 550 μm fiber, 1.0-1.5 J energy and 10-12 Hz frequency. b) lithotripsy with flexible endoscope: 270 μm fiber, 0.6-1.0 J energy and 6-10 Hz frequency. c) soft tissue resection in case of: c1) ureteral stricture, 365 μm fiber, 0.6 J energy and 14-16 Hz frequency; c2) urethral stricture, 365 μm fiber, 0.7 J energy and 16-18 Hz frequency; c3) upper urinary tract tumors, 365 μm fiber, 0.7 J energy and 16 Hz frequency; c4) bladder tumors 365 μm fiber, 0.8 J energy and 16-20 Hz frequency; c5) bladder neck strictures, 365 μm fiber, 1.0 J energy and 16-18 Hz frequency. CONCLUSIONS. In the light of these parameters, Ho-YAG laser is a very handy instrument for the treatment of both urinary stones and soft tissue lesions, which allows to put aside the current tools used for the same purposes.

In order to study molecules of relatively large molecular weight, pyrolysis techniques can be combined with mass spectrometry methods. In the past, pyrolysis—MS and pyrolysis—gas chromatography/mass spectrometry experiments on melanins and glycated proteins have been carried out; reproducibility was found to be improved by the use of Curie-point devices and by using laser irradiation. This study is a continuation of previous investigations, carried out on a variety of substrates, using laser pyrolysis—gas chromatography/mass spectrometry. For this work, a new pyrolyzer with a simpler specialized system and a lower volume (μl range) pyrolysis chamber was utilized.

The high temperatures generated by the holmium laser pulses during endourological treatments have been reported (4,6), the physical phenomena related to this event has never been interpreted. During our clinical experience we had some steel wires sheared by the holmium pulses (fig. 1), after microscopic analysis we considered that only the plasma was able to cause those damages (1, 2, 5).The aim of this work was to understand the phenomena produced by the holmium laser pulses through measurements oftemperature around the fiber tips, we determined the plasma formation thresholds for each fiber types, and also theplasma bubble dimensions.MATERIALS AND METHODS A series of experiments were conducted using an X-Y translator constructed with two micrometric slides, on the translator was fixed the optical fiber; by the slides the fiber tip was positioned near two thermocouples immersed in water (see fig. 2). A series of pulses from the Ho-YAG were delivered starting from an energy level of O.8J, and

A simple method, based on the use of a vacuum cell, is described for the coupling of an Nd: YAG Q-switched laser with 600 μm fibre optics. By such a device the usually observed damage of the fibre optical surface is completely avoided.

The 980 nm Ceralas D50 diode laser, produces homogeneous lesions on tissues of different nature. In our endourological tests we used the Ceralas D50 coupled with Comeg 24 ch laser resectoscope, and we treated 22 patients: n.5 bladder cancers, n.3 uretero pelvic junction obstructions, with hydronephrosis, n.3 urethra stenosis, n1 ureter stenosis, n.4 multiple upper tract transitional cell carcinomas, n.6 BPH treatments with VLAP modalities. Using the 1000 micrometers delivery fibers with different shaped tips, we obtained a bloodless sharp cut and easily vaporizations with minimum carbonizations, with power output in the range of 8-12 W, and 18-24W for VLAP.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A new 1,800-microns side fiber made of pure silica with laser beam deviation of 82 degrees and divergence of 18 degrees was inserted into a modified transurethral resectoscope and used to treat in vitro some prostates removed during radical prostatectomy. Sterilization of prostatic tissue with a depth of penetration of 12 mm was observed after treatment with 20 W for 2 min. Irradiation with 60 W for 1 min produced vaporization and explosion of the tissue and a depth of penetration of 15 mm. The laser resectoscope was then successfully employed for the treatment of 6 cases of benign prostatic hyperplasia (BPH) as well as in high risk patients with bulky bleeding bladder tumors (4 cases) and with transitional carcinoma of the prostate invading the parenchyma (2 cases). 3 patients with small size BPH underwent only laser irradiation. All others were submitted to traditional transurethral resection followed by laser treatment with Nd: YAG using the same instrument. Our laser resectoscope lowers costs since the side fiber is reusable for 4-5 treatments and brings laser treatment nearer to traditional endoscopic treatment, thereby making its application more comfortable for the urologist.

Optical fiber systems with lateral emission of laser radiation are currently used for laser treatment of benign prostatic hyperplasia (BPH). They can be classified in reflective or refractive systems in which a mirror or a prism, respectively, is connected to the fiber tip. Both systems are disposable making the cost of treatment too high. An alternative solution for refractive systems is the prismatic cut of the fiber tip. A side fiber of this type was conceived at the Department of Chemical Physics of the University of Venice and then patented. An Olympus 27ch transurethral resectoscope was also modified for use with our side fiber as well as with the resecting blade. Our modified resectoscope with a Nd-YAG laser has been clinically used for the laser treatment of BPH (6 cases), as well as in high risk patients with bulky bleeding bladder tumors (4 cases), and in transitional tumors of the prostate infiltrating the parenchyma (2 cases). Laser treatment with our resectoscope resembles traditional endoscopic treatment, guarantees the precision of fiber tip translation, and permits combined treatments with laser and traditional blade.

We used an excimer laser system (xenon-chloride at the wavelength of 308 nm) to treat totally occluded peripheral vessels in 71 patients. Energy was delivered through a multifiber catheter, which combines 12 (7F) or 18 (9F) fibers (260 (mu) diameter each), concentrically arranged. Balloon dilatation was associated to complete the procedure in 84% of the cases. The immediate success rate was 97%. The cumulative patency rate was 49% at one year. The major problems with this system were that the stiff multifiber tips caused dissections, and spasm; dead space/active space ratio of the catheter was unfavorable, allowing mechanical `dottering;' the maximum lumen obtained was considered inadequate. After this three year period, the goal of our clinical laser program is to develop a stand alone laser technique by employing a multifiber catheter which combines 130 - 150 fibers 100 (mu) diameter each, and features a quartz coated distal tip.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Laser lithotripsy is based on laser induced plasma formation. Successful stone fragmenting is dependent on power density at the fiber tip in contact with the stone and on the absorption of laser radiation by the stone itself. The use of the laser has been ineffective in the treatment of hard stones and of stones that absorb only minimal amounts of laser radiation. In our experimental and clinical studies we used Rifamycin (Rifocin) as a photosensitizer for the pulsed Dye laser and Sterile Indocyanine Green (Cardio Green) for the pulsed Alexandrite laser. We found that the use of these substances significantly increased the effectiveness of the laser in the treatment of those stones.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.