| 题名 | 生物组织的光学成像技术的理论和实验研究 |
| 作者 | 陈敏 |
| 学位类别 | 博士 |
| 答辩日期 | 1999 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 徐至展 |
| 关键词 | 生物组织 近红外光学成像 Monte Carlo模拟 时间分辨 软X射线 同轴全息 |
| 中文摘要 | 本论文的工作包括两部分：1）生物组织的光学成像术的理论研究：近红外光在生物组织中的传播；2）生物样品的软X射线全息成像的实验研究。第一部分：生物组织的光学成像术的理论研究：近红外光在生物组织中的传播 综述了生物组织光学成像的理论模型和实验方法，编制了Monte Carlo模拟软件，对近红外光在生物组织中的传播进行了系统的研究，取得了以下一些成果：1. 详细研究了在无限细光束和平行平面光束入射到组织中的能量衰减。在理论上证明了在无限细光束入射下蛇行光的能量衰减近似地呈指数衰减，从理论上佐证了时间分辨层析术的可行性。首次用Monte Carlo方法模拟了在无限宽光束入射下，积分时间为1ps、5ps、10ps、20ps、50ps、100ps和200ps下的光束的能量衰减。结果表明除了在入射光源附近，比尔定律适用，只是衰减系数减小，为面扫描成像提供了理论依据。2. 研究了时间分辨层析术的成像分辨率。从漫射近似理论出发，利用系统的点扩散函数首次详细地讨论了时间门的时间分辨率、探测器的有限大小对系统的成像分辨率的影响，以及成像分辨率与组织的厚度和积分时间的关系。3. 用Monte Carlo方法模拟了光在两层具有不同光学参数的组织中的传播，仔细地研究了吸收系数、散射系数和各项异性因子的差异对样品的漫反射率和漫透射率及透射表面的光强分布的影响。4. 将Monte Carlo方法扩展到用来模拟了脉冲光在多层组织中的时间分辨传播。对组织的三个光学参数即吸收系数、散射系数和各项异性因子进行了研究。发现光透过多层组织后其透射脉冲的形状相对于单层组织具有较大的差异。指出组织的吸收系数对成像分辨率有很大影响。5. 研究了有限宽光束入射到生物组织中的响应。用Monte Carlo方法模拟了高斯脉冲和平面圆光束入射到生物组织中的反射率、透射率及能流密度，并与无限细脉冲入射作了比较。第二部分：生物样品的软X射线全息实验研究 6. 综述了软X射线全息术的历史。对合肥同步辐射源的实验条件作了评价，确定了合肥同步辐射源上进行生物样品的软X射线全息的实验参数。7. 在合肥同步辐射源上进行了生物样品的软X射线全息实验研究。用光刻胶记录水窗波段的同轴软X射线的全息图，所用的光源为经线性单色仪单色化的800MeV电子存储环弯转磁铁辐射（3.2nm）。所用的生物样品为蜘蛛丝和大蒜茎内表皮。得到了国内第一张软X射线全息图，并用数字化方法得到了重现象，其分辨率< 2μm。研究了提高分辨率的方法。在该实验中，我们首次用部分相干光完成了软X射线全息成像研究，从而能在亮度较低的合肥同步辐射源上完成该项工作。 |
| 英文摘要 | This dissertation includes two parts: 1) Theoretical study on optical imaging in medicine: propagation of NIR photons in biological tissues: 2) Experimental study on soft X-ray in-line holography in biological sample. Part 1: Theoretical study on optical imaging in medicine: propagation of NIR photons in biological tissues Theoretical models and experimental methods of NIR optical imaging in medicine are reviewed, the program of Monte Carlo simulation is written using C language. The systematic analysis of photon propagation through turbid tissues is achieved and some important results are obtained as below: 1. The energy attenuation of photons through tissues is discussed when parallel-plane light illuminates. We first use Monte Carlo method to simulate the energy attenuation of photons in different temporal windows while infinite-width light illuminates biological tissues. The result shows Beer law holds within small temporal windows. 2. The image resolution of time-resolved imaging in tissues is calculated by using point spread function with a diffusion model. The effects of temporal resolution of time gate, finite aperture of detector on image resolution are first discussed in detail. 3. Photon propagation in two-layered is simulated using Monte Carlo method. The effects of the differences of three kinds of optical parameters between layered tissues on total diffuse reflectance total diffuse transmittance and the intensity distributions are discussed in detail. The internal photon fluency in tissues is also investigated. 4. The time-resolved propagation of pulsed photons through turbid tissues is simulated. We study the effects of the different optical parameters of the tissues on the shape of the transmittance curve in detail. 5. We study the response of finite-width light illuminating the tissues. The reflectance, transmittance and fluency are simulated. The results are compared with the illumination of infinitesimal pulse. Part II: Experimental study on soft X-ray holography in biological sample 1. The history of X-ray holography is reviewed. The experimental condition in Hefei National Synchrotron Radiation Laboratory is estimated and the experimental parameters are determined. 2. The experiments of soft X-ray holography are made in Hefei National Synchrotron Radiation Laboratory. X-ray Gabor in-line holograms of biological samples are recorded in photoresist. The holograms are reconstructed using numerical methods. The 3.2 nm soft X-ray used in experiments are the bending magnet radiation of a 800MeV electron storage ring and have been monochromatized by linear monochromator. The estimated resolution of the reconstructed are better than 2 micrometers and remails to be improved in the future. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15583]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 陈敏. 生物组织的光学成像技术的理论和实验研究[D]. 中国科学院上海光学精密机械研究所. 1999. |
| 个性服务 |
| 查看访问统计 |
| 相关权益政策 |
| 暂无数据 |
| 收藏/分享 |
除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。
修改评论