Orihuela E, Pow-Sang M, Cammack T, LaHaye M, Cowan D F, Warren M
Department of Surgery, University of Texas Medical Branch, Galveston, USA.
Arch Esp Urol. 1995 Mar;48(2):212-5.
To determine systematically the depth of coagulation necrosis induced during Nd: YAG laser irradiation in the canine prostate model, and to define the correlation of laser dose with depth of the lesions.
We investigated the effect of various dosimetries on prostatic tissue of 17 mongrel canines using laser power in the range of 8 to 60 watts (W) at varying exposure times, from 20 to 300 seconds (S). Applied energy ranged from 1,000 to 5,500 Joules (J).
Three distinct features were observed. First, deep coagulation necrosis was induced only with laser regimens of > or = 2,100J, suggesting that there is a threshold of energy that must be overcome in order to achieve significant coagulation depth. Second, the deepest coagulation necrosis was achieved with a low power slow-heating regimen (15W X 180S). Tissue surface changes appeared to be responsible for the reduced depth of coagulation necrosis seen with higher power regimens (> 20 W). Third, increasing the energy above 3,600J did not augment the depth of coagulation, suggesting that a steady state for temperature distribution is reached at that rate of heating.
Our study suggests that in the canine prostate, a low power slow-heating regimen of 15W X 180S may yield larger volumes of coagulation necrosis than other regimens.
系统测定钕钇铝石榴石激光照射犬前列腺模型时诱导的凝固性坏死深度，并明确激光剂量与病变深度的相关性。
我们使用8至60瓦（W）的激光功率，在20至300秒（S）的不同暴露时间下，研究了各种剂量测定法对17只杂种犬前列腺组织的影响。施加的能量范围为1000至5500焦耳（J）。
观察到三个明显特征。第一，仅在激光治疗方案≥2100焦耳时才诱导出深度凝固性坏死，这表明为了达到显著的凝固深度必须克服一个能量阈值。第二，低功率慢加热方案（15瓦×180秒）实现了最深的凝固性坏死。组织表面变化似乎是高功率治疗方案（>20瓦）时凝固性坏死深度降低的原因。第三，将能量增加到3600焦耳以上并没有增加凝固深度，这表明以该加热速率达到了温度分布的稳态。
我们的研究表明，在犬前列腺中，15瓦×180秒的低功率慢加热方案可能比其他方案产生更大体积的凝固性坏死。
