IEEE Trans Ultrason Ferroelectr Freq Control. 2017 Aug;64(8):1205-1211. doi: 10.1109/TUFFC.2017.2713599. Epub 2017 Jun 8.
Photoacoustic (PA) imaging detects acoustic signals generated by thermal expansion of a light-excited tissue or contrast agents. PA signal amplitude and image quality directly depend on the light fluence at the target depth. With conventional PA imaging systems, approximately 30% energy of incident light at the near-infrared region would be lost due to reflection on the skin surface. Such light loss directly leads to a reduction of PA signal and image quality. A new light delivery scheme that collects and redistributes reflected light energy was recently suggested, which is called the light catcher. In our previous study, proof of concept using a finite-element simulation model was shown and a laboratory-built prototype of the light catcher was applied on tissue-mimicking phantoms. In this paper, we present an elaborate prototype of a high-frequency PA probe with the light catcher fabricated using 3-D printing technology, which is conformal to a subcutaneous tumor in mice. The in vivo usefulness of the developed prototype was evaluated in a mouse tumor model. Equipped with the light catcher, PA signal amplitude from the clinical photosensitizer injected into the mouse tumor was enhanced by 33.7%, which is approximately equivalent to the percent light loss due to reflection on the skin.
光声（PA）成像是通过检测光激发组织或对比剂的热膨胀产生的声信号来进行的。PA 信号幅度和图像质量直接取决于目标深度处的光辐照度。在传统的 PA 成像系统中，近红外区域约有 30%的入射光会因皮肤表面的反射而损失。这种光损失直接导致 PA 信号和图像质量的下降。最近提出了一种新的光传输方案，该方案称为光收集器，可以收集和重新分配反射光能量。在我们之前的研究中，使用有限元模拟模型展示了概念验证，并在组织模拟体模上应用了实验室制造的光收集器原型。在本文中，我们提出了一种带有光收集器的高频 PA 探头的详细原型，该光收集器是使用 3D 打印技术制造的，与小鼠皮下肿瘤相贴合。在小鼠肿瘤模型中评估了所开发原型的体内实用性。配备光收集器后，从注射到小鼠肿瘤中的临床光敏剂获得的 PA 信号幅度增强了 33.7%，这大约相当于由于皮肤反射导致的光损失百分比。
