Optical Methods for Lesion Activity Assessment

项目来源

美国卫生和人类服务部基金(HHS)

项目主持人

GRISIUS, MARGARET

项目受资助机构

UNIVERSITY OF CALIFORNIA SAN FRANCISCO

立项年度

2020

立项时间

未公开

项目编号

5R01DE027335-03

项目级别

国家级

研究期限

未知 / 未知

受资助金额

383563.00美元

学科

Bioengineering;Clinical Research;Dental/Oral and Craniofacial Disease

学科代码

未公开

基金类别

Non-SBIR/STTR RPGs

关键词

未公开

参与者

FRIED, DANIEL

参与机构

NATIONAL INSTITUTE OF DENTAL & CRANIOFACIAL RESEARCH

项目标书摘要:BSTRACT The overall objective of this proposed research is to develop methods for the clinical assessment of lesion structure and activity. New imaging technologies employing non- ionizing radiation are needed to aid in caries diagnosis and management. It is not sufficient to simply detect caries lesions, methods are needed to assess the lesion activity and determine if chemical intervention is needed. Measurements of lesion structure and the optical and dimensional changes to lesions that occur during dehydration offer the potential for lesion activity assessment during a single examination. The central hypothesis underlying this proposal is that there are structural differences between active and arrested lesions and these differences can be quantified using near- IR (NIR) imaging methods. The objectives of this proposal will be achieved through the following specific aims: (1) To test the hypothesis that NIR reflectance measurements during lesion dehydration are more sensitive to changes in lesion structure and activity than existing methods and that NIR imaging can be used to assess the activity of coronal caries lesions in vivo. (2) To test the hypothesis that cross-polarization OCT (CP-OCT) can be used to assess changes in lesion structure and activity in the pits and fissures of primary teeth before and after chemical intervention. (3) To test the hypothesis that CP-OCT can be used to assess the activity of lesions on root surfaces and monitor the efficacy of conservative intervention in vivo. Success of this proposal will provide methods for assessing the activity of lesions in a single examination and for monitoring the efficacy of chemical intervention, thereby enabling the use of new intervention therapies to avert cavitation and restoration.

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  • 1.光纤偏振光学相干层析术关键技术研究

    • 关键词:
    • 偏振敏感光学相干层析术;双折射相位延迟;相对快轴方向;快轴绝对方向;手持式探头;单模光纤偏振特性;龋齿活性
    • 刘浩
    • 指导老师:南京理工大学 高万荣
    • 学位论文

    光学相干层析术(Optical coherence tomography,OCT)是一种非侵入式、高分辨率、高灵敏度的生物组织活体断层成像技术。偏振敏感OCT(Polarization sensitive OCT,PS-OCT)技术是传统OCT的一种发展,利用偏振光成像,通过检测生物组织背向散射光中包含的偏振特性信息,以诊断生物组织内部的早期病变,在临床诊断应用中有巨大的潜力。目前PS-OCT系统存在空间光路体积过大,光纤光路算法计算量大以及无法测量生物组织样品的快轴绝对方向等问题。本文提出采用全光纤PS-OCT来实现对人体牙齿成像和生物组织双折射快轴方位测量等,主要研究内容和创新点如下:为了实现对人体牙齿的在体成像,搭建了一套手持式光纤型谱域OCT系统。其中的手持式探头采用小型扫描振镜进行横向扫描,其结构紧凑,尺寸小且成本低,可以稳定地对活体组织进行检测。对离体牙齿和在体牙齿所获得的图像中,可以清晰地看到活体牙齿的牙釉质、牙本质和釉质本质界面等组织,验证了该系统的成像性能。为了克服单偏振态输入的全光纤PS-OCT系统中单模光纤带来的偏振影响,提出了一种基于Stokes-Mueller的方法。通过偏振控制器调节系统光纤的偏振态,可以准确提取出生物组织样品正常和烧伤时的双折射相位延迟和相对快轴方向。此外,通过两束正交偏振分量的光谱相减,可以一定程度上抑制散射光中的非偏振多次散射对图像质量的影响。为了精确获得生物样品的快轴绝对方向,提出了一种基于全光纤PS-OCT系统的改进算法。首先利用偏振控制器使得系统光纤的相位延迟为π的整数倍,使从样品表面反射回来的光的斯托克斯矢量为[0,1,0]T,建立一个基于穆勒矩阵的光纤系统理论模型,得出了生物组织样品的快轴绝对方位表达式。利用该算法对标准样品快轴绝对方位的测量误差约为3°。为了无损伤评估龋变活性状态,提出了基于PS-OCT、近红外反射成像和热成像方法相结合的检验矿化层厚度减小与龋齿活性状态之间相关性的实验设计。实验结果表明金刚石砂轮抛磨后的龋变区域的反射率强度和温度随脱水时间产生明显变化(P<0.05)。该研究结果为理解非活性龋齿病变机制提供了有关的证据,并表明亚表面龋变上方的透明矿化层极大地抑制了液体在龋变部位的扩散。

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