Multimodal imaging of functionalized nanoprobes

当探测活体生物组织时，光声成像是近年来出现的一种吸引人的生物成像技术，它结合了声学的高空间分辨率和光学的高对比度和分子探测能力。光声层析成像(PAT)是一种同时使用光学和超声传播的方法。潜在的物理过程开始于用脉冲激光激发组织中的吸收体。然后，内源或外源吸振器在振动中耗散可被宽带传感器检测到的能量。在动物身上，已经展示了在脑瘤、功能激活和分子成像方面的应用。人类的应用也在不断涌现，例如皮肤癌和乳腺癌的检测。尽管PAT实现了高分辨率和精致的图像，但也出现了类似于漫反射光学成像的量化问题。到达吸收体的光的分布是未知的，需要建模。这可以通过模拟光在组织中的传播来实现，但需要了解解剖学和组织分布的知识才能进行这些模拟。如果没有这种量化，在PAT中产生的图像对临床前研究人员的价值将是有限的，很明显，这是需要通过这种模式解决的下一个问题。

When probing biological tissues in vivo, photo-acoustic imaging has recently emerged as an appealing bio-imaging technique, which combines the high spatial resolution of acoustics with the high contrast and molecular probe capabilities associated with optics. Photo-Acoustic-Tomography (PAT) is a method using both optical and ultrasound propagation. The underlying physical process begins by exciting absorbers in tissues with pulsed laser light. Endogenous or exogenous absorbers then dissipate the energy in vibration that can be detected by wide band transducers. In animals, applications to brain tumours, functional activation, and molecular imaging have been demonstrated. Human applications are also emerging such as skin and breast cancer detection. Despite the high resolutions and exquisite images achieved by PAT, quantification issues akin to those found in diffuse optical imaging arise. The distribution of light reaching the absorbers is unknown and needs to be modeled. This can be done by simulating light propagation in tissues but knowledge of the anatomy and tissue distribution is necessary to perform those simulations. Without this quantification, the images generated in PAT will have limited value to the pre-clinical researcher and it becomes clear that this is the next issue that needs to be addressed by this modality.