Nd-YAG laser energy distribution in an artificial obstruction: Influence of lasing parameters in a model of laser angioplasty

1988 ◽  
Vol 8 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Rienk Rienks ◽  
Ruud M. Verdaasdonk ◽  
Cornelius Borst ◽  
Peter C. Smits ◽  
George Jambroes ◽  
...  
2020 ◽  
Vol 27 (1) ◽  
pp. 1-4
Author(s):  
Fatan Abshari ◽  
Zulfikar Ali

Objective: Transurethral lithotripsy using Holmium-YAG laser has been reported to be beneficial in breaking up bladder stones with large size (>4cm in diameter) with lower risk of mucosal injury and hematuria. The aim of this study is to evaluate the utilization of Holmium-YAG laser for the management of bladder stones at Kardinah General Hospital, Tegal. Material & Methods: This is a cross-sectional study conducted from January 2017 to March 2017. Patient’s demography, which included age, sex, length of surgery, stone size, and laser’s energy count were recorded. Results: We included 120 patients in this study. Mean of patients age in this study was 51.93 years old with age range were 41-85 years old. Most of the patients were male (109 vs 11) with a mean size of stone 25.09 ± 3.04 mm. Length of surgery ranges from 15 to 75 minutes and mean energy of the laser 28.99 ± 19.34 kJ. There was 100% stone’s clearance following surgery with no major complication occurred. Conclusion: Holmium-YAG laser is effective in managing bladder stones at Kardinah General Hospital particularly for large size stones. Length of surgery and energy of laser used depend on the stone size in which bigger stone size is associated with longer surgery time and bigger laser energy needed.


1991 ◽  
Vol 236 ◽  
Author(s):  
Francis X. Campos ◽  
Gabriela C. Weaver ◽  
Curtis J. Waltman ◽  
Stephen R. Leone

AbstractExposing a Si(100) surface to a pulsed beam of neutral Cl2 with high translational energy results in etching at a rate faster than that seen with chlorine at thermal energies. The Cl2 beam used in these experiments is produced by laser vaporization of cryogenic films. It has a broad energy distribution which can be varied by changing laser energy and film thickness. Beams with mean energies as low as 0.4 eV result in etching =10 times faster than etching by thermal Cl2. When Cl2 beams are used which have considerable flux above 3 eV, the etching rate increases by a further factor of 3.6 ± 0.6. This rate increase, which occurs at energies just above the Si-Si bond energy, suggests that kinetic energy can be efficiently utilized to break surface bonds.


2011 ◽  
Vol 287-290 ◽  
pp. 2401-2406 ◽  
Author(s):  
Ai Qin Duan ◽  
Shui Li Gong

In this paper, the keyhole of YAG laser welding 5A90 Al-Li alloy was observed and measured through the high speed camera. The characteristics of the keyhole and the effects of welding parameters were studied. The characteristics of the absorption of laser energy and the susceptivity for heat input in welding 5A90 were given. The results show that in this welding condition, the keyhole of laser welding 5A90 is nearly a taper and the highest temperature area is in the bottom. There are clear effects of heat input on the characteristics, especially the surface radius of keyhole and plasma/vapor in keyhole. Another phenomena is observed that sometime plasma/vapor could disappear in 0.3ms welding time, and this feature will be more remarkable as decrease of heat input. It shows that the absorption of energy is unsteady. It is known that when this instability reaches a certain value, an unsteady weld will be formed.


Author(s):  
Peter O’Kane ◽  
Simon Redwood

The first medical application of laser was reported by Dr Leon Goldman who, in 1962, reported the use of ruby and carbon dioxide (CO2) lasers in dermatology. In cardiovascular disease, early laser use was confined to cadaver vessels, animal models, and arteries located in freshly amputated limbs, until eventually work progressed to the use of laser energy to salvage an ischaemic limb in 1984. The concept of using laser to remove atherosclerotic material in coronary arteries developed as an alternative strategy to simply modifying the shape of an obstructed lumen as occurs with simple balloon angioplasty. Expectations grew that this new biomedical technology may overcome the low success rate and high complication rate of lesions considered non-ideal for balloon angioplasty. However, initial successful reports could not be replicated. Furthermore, underdeveloped catheter technology and limited appreciation of laser/tissue interactions meant that a cure for restenosis was not in fact discovered and laser coronary angioplasty became isolated to only a few centres in the world. However, more recently with advancement in both catheter technology and technique, excimer coronary laser angioplasty (ELCA) has been rediscovered for use in specific subsets of percutaneous coronary interventions (PCIs). This chapter outlines the basic principles of ELCA and important practical aspects for using the device in contemporary PCI. A discussion of the current indications for clinical use follows and these are highlighted by clinical case examples.


2019 ◽  
Vol 15 (4) ◽  
pp. 391.e1-391.e7 ◽  
Author(s):  
C. Esposito ◽  
L. Masieri ◽  
V. Bagnara ◽  
B. Tokar ◽  
A. Golebiewski ◽  
...  

Angiology ◽  
1990 ◽  
Vol 41 (6) ◽  
pp. 453-462 ◽  
Author(s):  
Simon Ashley ◽  
Stephen G. Brooks ◽  
Abdurrazzak A. Gehani ◽  
Ralph C. Kester ◽  
Michael R. Rees

2016 ◽  
Vol 91 (1-4) ◽  
pp. 1129-1143 ◽  
Author(s):  
Jie Ning ◽  
Lin-Jie Zhang ◽  
Suck-Joo Na ◽  
Xian-Qing Yin ◽  
Jing Niu ◽  
...  

1992 ◽  
Vol 13 (1) ◽  
pp. 27-35
Author(s):  
Kenji Kawachi ◽  
Makoto Doi ◽  
Kazuhito Osada ◽  
Shin Ishimaru ◽  
Kinichi Furukawa

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