Aim

The aim of this study was to compare the thermal effects of Ho:YAG and Tm-fiber lasers during lithotripsy in an in-vitro model via real-time temperature measurement.

Methods

We compared a Ho:YAG laser (p_av up to 100 W, Lumenis, Yokneam, Israel) and a superpulse Tm-fiber laser (SP TFL, p_av up to 40 W, NTO IRE-Polus, Fryazino, Russia), both equipped with 200 µm bare-ended fibers. The following settings were used: 0.2 J, 40 Hz (nominal p_av 8 W). Power meter FieldMaxII-TO (Coherent, Santa Clara, CA, USA) was used to verify output laser power (p_av). Each laser was fired for 60 s in two setups: (1) thermos-insulated (quasi-adiabatic) cuvette; (2) actively irrigated setup with precise flow control (irrigation rates 0, 10, 35 mL/min).

Results

Power measurements performed before the test revealed a 10% power drop in Ho:YAG (up to 7.2 ± 0.1 W) and 6.25% power drop in SP TFL (up to 7.5 ± 0.1). At the second step of our experiment, irrigation reduced the respective temperatures in the same manner for both lasers (e.g., at 35 mL/s SP TFL − 1.9 °C; for Ho:YAG laser − 2.8 °C at 60 s).

Conclusion

SP TFL and Ho:YAG lasers are not different in terms of volume-averaged temperature increase when the same settings are used in both lasers. Local temperature rises may fluctuate to some degree and differ for the two lasers due to varying jet streaming caused by non-uniform heating of the aqueous medium by laser light.

中文翻译：

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Ho：YAG激光和新型Tm光纤激光在碎石术中的温度变化：一项体外比较研究。

目标

这项研究的目的是通过实时温度测量在体外模型中比较Ho：YAG和Tm光纤激光器在碎石过程中的热效应。

方法

我们比较了钬激光（p _AV高达100 W，科医人，YOKNEAM，以色列）和superpulse TM-光纤激光器（SP TFL，p _AV高达40 W，NTO IRE-波鲁斯，弗里亚济诺，俄罗斯），既配备200 µm裸光纤。以下设置用于：为0.2J，40赫兹（标称p _AV 8 W）。功率计FieldMaxII-TO（美国加利福尼亚州圣克拉拉市的Coherent公司）用于验证输出激光功率（p _av）。每个激光器以两种设置发射60 s：（1）隔热的（准绝热）比色杯；（2）具有精确流量控制的主动灌溉设置（灌溉速率0、10、35 mL / min）。

结果

测试之前进行的功率测量显示，Ho：YAG的功率下降了10％（最高7.2±0.1 W），SP TFL的功率下降了6.25％（最高7.5±0.1）。在我们实验的第二步，冲洗以相同的方式降低了两个激光器的各自温度（例如，在35 mL / s SP TFL-1.9°C；对于Ho：YAG激光器-2.8°C在60 s时）。

结论

当两个激光器使用相同的设置时，SP TFL和Ho：YAG激光器在体积平均温度升高方面没有区别。由于由激光对水性介质的不均匀加热引起的喷射流变化，局部温度升高可能会在一定程度上波动，并且对于两个激光器而言会有所不同。