目的:超声敏感的高沸点全氟化碳F8TAC18-PFOB乳剂先前在离体猪肝的聚焦超声加热过程中表现出热增强,肾脏和层流模型。这项研究的主要目的是评估湍流条件下的加热,观察灌注效应,根据声学吸收量化加热并对实验数据进行建模。
方法:在本研究中,类似的全氟化碳乳液以0.07、0.13、0.19和0.25%v:v的递增浓度通过渗透的湍流模型循环,比层流体模更能代表生物组织。浓度仅代表灌注液中的液滴含量,而不是整个横截面的液滴浓度。用磁共振测温法测量温度,在67W的聚焦超声检查期间,95%的占空比和33s的持续时间。这些被用于生物热方程模拟中,以模拟研究热现象。通过使脱气和去离子水循环通过没有液滴的流动模型来将温度变化与对照条件进行比较。
结果:这些1.24µm直径的液滴在0.25%v:v时,使用0.1mLs-1流速,声吸收系数从0.0%v:v时的0.93±0.05增加到0.25%v:v时的1.82±0.22m-1。在没有0.25%v:v灌注的情况下,从0.0%v:v时的1.23±0.07m-1增加到1.65±0.17m-1。
结论:结果进一步支持先前报道的F8TAC18-PFOB乳剂的热增强,量化小浓度间隔下增加的吸收,说明了可以在各种内脏组织模型中观察到的效果,并提供了一种模拟未经测试的场景的方法。
Sonosensitive high-boiling point perfluorocarbon F8TAC18-PFOB emulsions previously exhibited thermal enhancement during focused ultrasound heating in ex vivo pig livers, kidneys and a laminar flow phantom. The main objectives of this study were to evaluate heating under turbulent conditions, observe perfusion effects, quantify heating in terms of acoustic absorption and model the experimental data.
In this study, similar perfluorocarbon emulsions were circulated at incremental concentrations of 0.07, 0.13, 0.19 and 0.25% v:v through a percolated turbulent flow phantom, more representative of the biological tissue than a laminar flow phantom. The concentrations represent the droplet content in only the perfused fluid, rather than the droplet concentration throughout the entire cross-section. The temperature was measured with magnetic resonance thermometry, during focused ultrasound sonications of 67 W, 95% duty cycle and 33 s duration. These were used in Bioheat equation simulations to investigate in silico the thermal phenomena. The temperature change was compared with the control condition by circulating de-gassed and de-ionized water through the flow phantom without droplets.
With these 1.24 µm diameter droplets at 0.25% v:v, the acoustic absorption coefficient increased from 0.93 ± 0.05 at 0.0% v:v to 1.82 ± 0.22 m-1 at 0.25% v:v using a 0.1 mL s-1 flow rate. Without perfusion at 0.25% v:v, an increase was observed from 1.23 ± 0.07 m-1 at 0.0% v:v to 1.65 ± 0.17 m-1.
The results further support previously reported thermal enhancement with F8TAC18-PFOB emulsion, quantified the increased absorption at small concentration intervals, illustrated that the effects can be observed in a variety of visceral tissue models and provided a method to simulate untested scenarios.