Sturesson C
Department of Physics, Lund Institute of Technology, Sweden.
Lasers Surg Med. 1998;22(1):51-7. doi: 10.1002/(sici)1096-9101(1998)22:1<51::aid-lsm12>3.0.co;2-b.
The size of laser-induced coagulated lesions produced in porcine muscle in vitro using a cylindrical diffusing fiber tip and a conductive heat source, made by covering the diffuser with a hollow steel needle, were compared to investigate the influence of charring.
Light from a Nd:YAG laser was utilized for thermotherapy. A theoretical model for calculating tissue temperature was used to predict the experimental results and to simulate in vivo treatments.
The metal-covered tip produced carbonization and tissue vaporization that was not found with the diffuser. After 20 min of irradiation at a laser power of 7 W, the coagulated volumes with and without carbonization were found to be 13.1 cm3 (range 12.4-14.1 cm3, n = 4) and 12.2 cm3 (range 11.5-13.4 cm3, n = 4), respectively. Mathematical simulations showed that in unperfused tissue, a diffusing laser heat source produces smaller lesions than does a conductive heat source at the same power, the difference in coagulated volume becoming smaller with increased treatment time and increased power.
Using cylindrical diffusers, interstitial laser-induced thermotherapy without carbonization at the fiber tip can be as efficient as treatment with carbonization.
使用圆柱形扩散光纤尖端和通过用空心钢针覆盖扩散器制成的传导热源，在体外猪肌肉中产生激光诱导的凝固性病变，比较其大小以研究炭化的影响。
使用Nd:YAG激光进行热疗。利用计算组织温度的理论模型预测实验结果并模拟体内治疗。
金属覆盖的尖端产生了扩散器未出现的碳化和组织汽化现象。在7W激光功率下照射20分钟后，发现有碳化和无碳化的凝固体积分别为13.1cm³（范围12.4 - 14.1cm³，n = 4）和12.2cm³（范围11.5 - 13.4cm³，n = 4）。数学模拟表明，在未灌注组织中，相同功率下扩散激光热源产生的病变比传导热源小，随着治疗时间延长和功率增加，凝固体积差异变小。
使用圆柱形扩散器，光纤尖端无碳化的间质激光诱导热疗可与有碳化的治疗一样有效。
