Single-pixel diffuse optical tomography scanner for dynamic functional imaging

用于动态功能成像的单像素漫反射光学断层扫描仪

• 批准号: RGPIN-2017-06337
• 负责人: Diop, Mamadou
• 金额: $ 1.53万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=711573
• 关键词: Single; pixel; diffuse; optical; tomography

Rational and Objective Diffuse optical tomography (DOT) is a low-cost imaging modality that can provide three-dimensional (3D) images of tissue absorption, which, in the near-infrared range, is mainly due to hemoglobin and water. By measuring tissue absorption at multiple wavelengths, tomographic functional images can be generated and used to detect localized physiological abnormalities. It is this capacity to noninvasively image tissue physiological parameters (and to do so using safe, portable instruments) that makes DOT such an attractive technology. While DOT has numerous advantages, its widespread adoption as a functional imaging modality has been restricted by the current tradeoff between spatial and temporal resolution. That is, current methods can either acquire data at high speed with poor spatial resolution, or at millimeter resolution but with poor temporal resolution. The objective of this research program is to address this critical limitation. Research Plan 1) We will build a DOT scanner based on: i) Early-photons imaging: These photons travel along paths that are confined close to the line of sight between the source and detector (quasi-mimicking X-rays), which reduces image blurring and significantly improves spatial resolution. ii) Wide-field patterned illumination: A digital micro-mirror device (DMD), made of a 2D array of micro-mirrors that can be individually turned “ON” or “OFF”, will be used to generate wide-field patterned illumination on the surface of the tissue. We will leverage recent advances in DMDs technology that produced units that can generate light patterns at very high speed (up to 23 kHz) with high light output (up to 48%), to build a fast and efficient illumination system. iii) Compressive detection: Light transmitted through the tissue will be projected onto a 2nd DMD (to spatially encode the light intensity), then integrated by a single photodetector. Notice that we will be using a single-pixel camera to generate 3D images without scanning or multiplexing. 2) We will develop an image reconstruction software based on accurate Monte Carlo modeling of early-photons propagation in tissue. 3) The spatial resolution of the scanner will be quantified using tissue-mimicking phantoms with spatially-resolved features. 4) The dynamic imaging capability of the system will be tested in an animal model of localized ischemia. Impact The research program detailed in this proposal will lead to the development of a DOT scanner capable of fast 3D imaging of thick tissue (up to 60-mm thickness) with millimeter resolution. Such a scanner will enable dynamic imaging of molecular tracers to develop methods for i) small animal molecular imaging, ii) monitoring treatment response in inflammatory arthritis, and iii) predicting response to chemotherapy in breast cancer.

理性客观 漫反射光学断层扫描 (DOT) 是一种低成本成像方式，可以提供吸收组织的三维 (3D) 图像，在近红外范围内，主要是由于血红蛋白和水在多个条件下测量组织吸收。借助波长，可以生成断层扫描功能图像并用于检测局部生理异常。正是这种对生理组织参数进行无创成像的能力（并使用安全、便携式仪器来实现）使 DOT 成为一项颇具吸引力的技术。具有许多优点，但其作为功能成像模式的广泛采用受到当前空间分辨率和时间分辨率之间的权衡的限制，也就是说，当前的方法要么可以以较差的空间分辨率高速采集数据，要么以毫米分辨率采集但时间分辨率较差的数据。解决。 该研究计划的目标是解决这一关键限制。 研究计划 1）我们将基于以下内容构建 DOT 扫描仪： i) 早期光子成像：这些光子沿着靠近源和探测器之间视线的路径传播（准模拟 X 射线），这减少了图像模糊并显着提高了空间分辨率。 ii) 宽视场图案照明：由可单独“打开”或“关闭”的二维微镜阵列组成的数字微镜器件（DMD）将用于生成宽视场图案照明我们将利用 DMD 技术的最新进展，生产能够以极高的速度（高达 23 kHz）产生光图案并具有高光输出（高达 48%）的装置。快速高效的照明系统。 iii) 压缩检测：穿过组织的光将投射到第二个 DMD（对光强度进行空间编码），然后由单个光电探测器集成。请注意，我们将使用单像素相机生成 3D 图像，而无需扫描。或多路复用。 2）我们将开发一种基于组织中早期光子传播的精确蒙特卡罗模型的图像重建软件。 3) 扫描仪的空间分辨率将使用具有空间分辨特征的模拟组织模型来量化。 4）系统的动态成像能力将在局部缺血的动物模型中进行测试。 影响 该提案中详细介绍的研究计划将导致开发能够以毫米分辨率对厚组织（厚度高达 60 毫米）进行快速 3D 成像的 DOT 扫描仪。这种扫描仪将使分子示踪剂的动态成像成为可能，从而开发用于分子示踪剂的方法。 i) 小动物分子成像，ii) 监测炎症性关节炎的治疗反应，以及 iii) 预测乳腺癌化疗的反应。