Optoacoustic microscopy at multiple discrete frequencies
Optoacoustic microscopy at multiple discrete frequencies
复制标题
DOI：
10.1038/s41377-018-0101-2
复制
发表时间：
2018-12-19
影响因子：
19.4
通讯作者：
Ntziachristos, Vasilis
中科院分区：
文献类型：
--
作者：
Kellnberger, Stephan;Soliman, Dominik;Ntziachristos, Vasilis
光声（光声）感测采用瞬态能量的照射，并且通常使用纳秒光子脉冲在时域中实现。然而，高能量短光子脉冲的产生需要复杂的激光技术，该技术施加低脉冲重复频率（PRF）并限制同时可用于光谱成像的波长的数量。为了避免在时域工作的限制，我们已经开发了频域光声显微镜（FDOM），其中光强度在多个离散频率调制。我们将FDOM与多光子显微镜集成到一个混合系统中，我们研究了图像形成和调制频率之间的关系，展示了高保真度图像，其中来自幻影和体内的调制频率越来越多，并确定了在多个频率下进行的光声测量中的冗余。我们证明，由于高重复率，FDOM实现的信号-噪声比类似的时域方法，使用常用的激光二极管。此外，我们通过实验证实了在离散调制频率下频域实现的各种优点，包括在不同调制频率下进行的两个波长下的并发照明，以及基于光声多普勒效应在微流体芯片和体内的流量测量。此外，我们讨论了如何FDOM重新定义的可能性，通过利用在频域工作的优势，光声成像。
Optoacoustic (photoacoustic) sensing employs illumination of transient energy and is typically implemented in the time domain using nanosecond photon pulses. However, the generation of high-energy short photon pulses requires complex laser technology that imposes a low pulse repetition frequency (PRF) and limits the number of wavelengths that are concurrently available for spectral imaging. To avoid the limitations of working in the time domain, we have developed frequency-domain optoacoustic microscopy (FDOM), in which light intensity is modulated at multiple discrete frequencies. We integrated FDOM into a hybrid system with multiphoton microscopy, and we examine the relationship between image formation and modulation frequency, showcase high-fidelity images with increasing numbers of modulation frequencies from phantoms and in vivo, and identify a redundancy in optoacoustic measurements performed at multiple frequencies. We demonstrate that due to high repetition rates, FDOM achieves signal-to-noise ratios similar to those obtained by time-domain methods, using commonly available laser diodes. Moreover, we experimentally confirm various advantages of the frequency-domain implementation at discrete modulation frequencies, including concurrent illumination at two wavelengths that are carried out at different modulation frequencies as well as flow measurements in microfluidic chips and in vivo based on the optoacoustic Doppler effect. Furthermore, we discuss how FDOM redefines possibilities for optoacoustic imaging by capitalizing on the advantages of working in the frequency domain.