Er∶YAG激光切除骨组织的定量研究

Quantitative study of ablation of bone tissues by Er:YAG laser light

七十年代,二氧化碳激光作为外科手术刀已用于临床,激光切骨的基础研究也相继开展,如镫骨切除术、鼻泪囊造口术、上颌骨肿瘤切除术等。近年来,随着中红外激光器的研制,特别是超短脉冲激光技术的发展,Q-开关、锁模激光器等的医学应用也得到了进一步探索。大量生物学研究表明,3μm中红外激光对各种组织(角膜、皮肤、动脉粥样硬化斑块、骨等)均有切除作用,它对邻近组织造成的热损伤,要比二氧化碳(CO_2)、氩离子(Ar^+)、连续掺钕钇铝石榴石(Nd:YAG)激光所导致的轻。 本研究着重探讨Er:YAG激光在各种不同的脉冲重复频率之下,单脉冲能量密度与单脉冲切割深度的定量关系。根据实验数据按指定的数学模型拟合结果证实,在一定的照射能量密度范围内,单脉冲切割深度与单脉冲能量密度的对数成线性关系。

Canine femurs were ablated with an Er:YAG laser (2.94μm) with a pulseduration of 250μs. The bone ablation characteristics at four difierent pulse repetition rates (l-4Hz), were studied. The ablation depth versus energy density per pulse seems to follow an exponential function for large range of energy density. The increase of ablation ratio versus energy density at 1Hz was the highest, 2Hz the second, when the energy density levels were less than about 100J/cm.