Multimodal imaging of functionalized nanoprobes

当探测生物组织在体内，光声成像最近出现作为一个有吸引力的生物成像技术，它结合了高空间分辨率的声学与高对比度和分子探针的能力与光学。光声层析成像（PAT）是一种同时使用光学和超声传播的方法。基本的物理过程开始于用脉冲激光激发组织中的吸收体。然后，内源或外源吸收器在振动中耗散能量，该振动可以由宽带换能器检测到。 在动物中，已经证明了对脑肿瘤、功能激活和分子成像的应用。人类应用也正在出现，如皮肤癌和乳腺癌检测。尽管PAT实现了高分辨率和精致的图像，但出现了类似于漫射光学成像中发现的量化问题。到达吸收器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完成，但是解剖学和组织分布的知识对于执行这些模拟是必要的。如果没有这种量化，PAT中生成的图像对临床前研究人员的价值将有限，很明显，这是需要通过这种方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.