NearIR Photon-counting Camera for Diffuse Optical Tomography

描述(申请人提供)：早期发现和常规临床筛查是控制癌症的第一道防线。2005年，美国有超过570,280人死于癌症。在肿瘤的医学成像方面已经取得了重大进展；然而，这些技术中的许多都太昂贵了，无法实施常规筛查。扩散光学断层扫描(DOT)和扩散相关断层扫描(DCT)对血流进行成像，有望为常规的非侵入性癌症筛查提供一种方法，通过减少或消除辐射暴露来增加筛查程序的频率。遗憾的是，许多单光子计数探测器元件的需求昂贵且体积庞大，这限制了DCT仪器的发展。该项目的第一阶段资金支持了一种新成像技术的成功开发，该技术克服了传统CMOS(互补对称金属氧化物半导体)、APS(有源像素传感器)和CCD(电荷耦合器件)成像技术的限制，并为DCT成像提供了必要的基础。在第一阶段，我们设计、制作并测试了能够在近红外光谱范围内具有单光子灵敏度的CMOS雪崩光电二极管像素，其定时抖动小于350ps。这些CMOS盖革光电二极管(GPD)像素将入射光信号数字化，解决了许多噪声问题，这些问题限制了CMOSAPS相机像素在高速、高灵敏度和高空间分辨率应用(如DCT)中的使用。第二阶段的目标是开发一种完全集成的近红外数码相机芯片，用于血流的DCT成像。这种全数字的CMOS成像技术通过使用多个探测器元件来满足提供高信噪比DCT图像的苛刻要求。在第二阶段的工作中，我们建议实施第一阶段确定的成功的像素设计，以构建将被整合到贴片中的原型芯片。我们将在我们的合作者，宾夕法尼亚大学的A.Yodh博士的实验室里对模体进行DCT成像。乳房组织的诊断和成像，以及与运动相关的损伤，代表了拟议的DCT仪器的临床目标。这项工作通过使用红光对乳腺肿瘤中增加的血流进行非侵入性成像，改善了早期癌症诊断。

DESCRIPTION (provided by applicant): Early detection and routine clinical screening represent the first line of defense for managing cancer, a disease that claimed over 570,280 lives in the U.S. during the year 2005. Significant advances have been made in the medical imaging of tumors; however, many of these techniques are too expensive to be implemented for routine screening. Diffuse optical tomography (DOT) and diffuse correlation tomography (DCT), which images blood flow, promises to provide a method for routine, non-invasive cancer screening that increases the frequency of screening procedures by reducing, or eliminating, the exposure to radiation. Unfortunately, the need for many single photon-counting detector elements, which are expensive and bulky, constrains the development of DCT instruments. The Phase I funding for this project supported the successful development of a new imaging technology that surmounts the limitations of conventional CMOS (complementary-symmetry metal-oxide-semiconductor) APS (Active Pixel Sensor) and CCD (Charge-Coupled Device) imaging technologies and provides the necessary foundation for DCT imaging. In Phase I, we designed, fabricated and tested CMOS avalanche photodiode pixel capable of single optical photon sensitivity, in the near infrared region of the spectrum, with a timing jitter of less than 350 ps. These CMOS Geiger photodiode (GPD) pixels digitize the incident photo-signal, which solves many of the noise issues that have limited the use of CMOS APS camera pixels for high-speed, high- sensitivity, and high spatial-resolution applications, such as DCT. The Phase II goal is to develop a fully integrated, nearIR digital camera chip for DCT imaging of blood flow. This all-digital, CMOS imaging technology fulfills the demanding requirements for providing high signal-to-noise DCT images through the use of many detector elements. In the Phase II effort, we propose to implement the successful pixel designs, identified in Phase I, to construct a prototype chip that will be incorporated into a patch. We will perform DCT imaging of phantoms in the laboratory of our collaborator, Dr. A. Yodh at the University of Pennsylvania. The diagnosis and imaging of breast tissue, as well as sport related injuries, represents the clinical target of the proposed DCT instrument. This effort improves early cancer diagnosis by non-invasively imaging the increased blood flow in breast tumors using red light.