Cardiovascular Laser Application

With the invention of the laser, many clinical disciplines have taken advantage of this new energy source. Its precision, intensity and energy density is superior to all other known surgical devices. Based on the principle of light amplification from a photon-emitting resonator, the monochromaticity, collimation and coherence provide the high-energy density of the laser beam for medical applications. The state-of-the-art and future potential of laser use in cardiovascular diseases will be reviewed. Most of the work in this field has been accomplished during the past decade with numerous research projects. Although many technical advances have been made, so far the results in cardiovascular medicine are in the areas of vessel anastomosis, ablation of conduction passes for arrhythmia therapy, and angioplasty. In this paper, special attention will be given to the recent success in XeCl excimer laser application for photodecomposition of tissue with a goal of improved recanalization. The high-power density of the XeCl excimer laser provides significant advantages for the disruption of both embolic and calcified plaque. Regardless of the type of tissue ablated, gross, histologic, and ultra-structural analysis confirmed the absence of thermal injury in luminar recanalization as well as in animal studies. Progress in the manufacture of catheters, with multiple very small diameter fibers, led to the decisive breakthrough in clinical laser angioplasty. Peripheral as well as coronary arteries have been successfully recanalized followed by balloon dilatation. The ease of application and the success achieved thus far have resulted in an optimistic assessment for laser medicine.     

氩激光治疗中心性浆液性脉络膜视网膜病变

应用氩绿激光光凝治疗中心性浆液性脉络膜视网膜病变36例41只眼。结果视力≥1.0者从术前的17.1％增加到术后的63.5％,而视力≤0.6者从术前的61％降低到术后14.6％,术后1周至1月,多数患眼视网膜下液全部吸收,部分患眼中心凹反光重显。结果还显示术后视力与病程长短有关,但术后视力与渗漏点的方位、渗漏点中心凹距离以及神经上皮脱离的大小无关。     

钕钇铝石榴石激光治疗后囊混浊（353例）

采用钕钆铝石榴石激光切除白内障囊外摘除术后１０１例后房人工晶体植入后２５２例的后囊混浊共３５３例，激光治疗疗后视力均明显提高，矫正视力＞１．０者占８２．４％，无１例＜０．５。无明显并发症。     

Quantitative study of the morphological changes in the thyroid gland following IR laser radiation

The morphological changes produced in the thyroid glands of albino rats following radiation with a 904 nm infrared laser were studied. Two different levels of radiation were applied: 46.8 J/cm² and 140.4 J/cm². Evaluation of the changes in the densities of the epithelial, colloidal and follicular volumes and of the activation index revealed that the laser beam produced changes in the thyroid parenchyma. It was observed that there was a direct relationship between the severity of the lesion and the radiation energy applied.     

Nd：YAG激光对牙本质钙／磷比值的影响

为探讨Ｎｄ：ＹＡＧ激光对牙本质矿物含量的影响，应用扫描电镜和能谱仪定点测量５０个上前牙标本的根管壁（激光照射工和正常对比区）的钙、磷含量，结果表明，照射区牙本质钙／磷（Ｃａ／Ｐ）比值高于对比区，当激光能量达１５Ｗ以上时变化更为显著，提示Ｎｄ：ＹＡＧ激光能提高牙本质的钙化程度。     

钕激光照射对大鼠肿瘤生长的抑制作用

目的:研究钕激光照射对大鼠肿瘤生长的抑制作用.方法:采用钕激光在实验组荷瘤大鼠的肿瘤区及其肿瘤区周围进行照射,并观察抑制肿瘤的效果.结果:实验组大鼠肿瘤体的生长速度明显慢于对照组大鼠肿瘤体的生长速度.结论:用钕激光照射对抑制癌肿瘤的生长速度有明显的作用.     

Laser irradiation and balloon dilatation in experimental transluminal angioplasty

Percutaneous transluminal balloon angioplasty (PTA) is being currently used in patients with coronary artery disease. Laser irradiation (LI) has been effective in vaporizing atherosclerotic plaques. The purpose of this work was twofold: to compare PTA and LI techniques in the recanalization of experimental obstructive arterial lesions, and to evaluate the possibility of reducing the failures and local complications and increasing the success rate of PTA by the combined use of LI. Atherosclerotic iliac stenoses were induced in 27 rabbits; lesions were evaluated angiographically before and after intervention and were studied histologically and by electron microscopy. Argon-ion LI delivered through microlens-tip optic fibers reduced the stenotic area from 64.2 +/- 21.8% to 40.3 +/- 10.7% (n = 10, P less than .01) and PTA from 60.7 +/- 15.9% to 30.4 +/- 7.7% (n = 9, P less than .01). However, percentage reduction was higher in PTA-treated stenoses (48.4 +/- 10.1% vs 34.5 +/- 13.5%, P less than .0125). In eight more rabbits, low power LI (4.55 +/- 1.25 J) was delivered after PTA in dilated segments. Post-PTA LI further decreased stenoses (from 31.2 +/- 7.8% to 29.1 +/- 8.1%, P less than .0125); laser-irradiated segments showed diffuse carbonization of the disrupted intimal layer. The normalized transtenotic pressure gradient decreased significantly in all groups: LI reduced the gradient from .40 +/- .25 to .17 +/- .07 (P = .005); PTA from .37 +/- .14 to .11 +/- .04 (P = .001); LI after PTA from .40 +/- .16 to .12 +/- .06 (P = .001). Thus, LI is effective (less than PTA) in relieving experimental atherosclerotic stenoses and seems useful when combined with PTA.