Combined diffuse optical tomography (DOT) and MRI system for cancer imaging in small animals
Combined diffuse optical tomography (DOT) and MRI system for cancer imaging in small animals
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DOI：
10.1177/153303460600500407
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发表时间：
2006-08-01
影响因子：
2.8
通讯作者：
Nalcioglu, Orhan
中科院分区：
文献类型：
--
作者：
Gulsen, Gultekin;Birgul, Ozlem;Nalcioglu, Orhan
最近，人们对开发用于肿瘤学研究和临床研究的多模态成像技术产生了很大的兴趣，目的是获得补充信息，从而改善肿瘤的检测和表征。在目前的工作中，给出了用于小动物双模态成像的组合MR漫射光学成像系统的细节。作为这项工作的一部分，多光谱频域漫射光学断层扫描系统与 MRI 系统集成。这里，网络分析仪为激光二极管提供射频调制信号，并测量检测到的信号的幅度和相位。光电倍增管用于测量低电平信号。该光学成像系统与 4T MRI 系统的集成是通过在 MR 磁体内部集成光纤自适应接口来实现的。共同配准是通过利用基准标记的特殊探针设计来实现的。使用有限元算法求解扩散方程，并实现基于该正向求解器的逆向求解器，以根据采集的数据计算吸收和散射图。 MR先验信息用于指导光学重建算法。模型研究表明，当使用 MR 先验信息时，位于 64 mm 模型中的不规则物体中的 7 mm 夹杂物的吸收系数可恢复为 11% 的误差。 ENU诱导的肿瘤模型用于测试系统的体内性能。
Recently, there has been a great amount of interest in developing multi-modality imaging techniques for oncologic research and clinical studies with the aim of obtaining complementary information and, thus, improving the detection and characterization of tumors. In this present work, the details of a combined MR-diffuse optical imaging system for dual-modality imaging of small animals are given. As a part of this effort, a multi-spectral frequency domain diffuse optical tomography system is integrated with an MRI system. Here, a network analyzer provides the rf modulation signal for the laser diodes and measures the amplitude and the phase of the detected signals. Photomultiplier tubes are utilized to measure low-level signals. The integration of this optical imaging system with the 4T MRI system is realized by incorporating a fiber adaptive interface inside the MR magnet. Coregistration is achieved by a special probe design utilizing fiducial markers. A finite element algorithm is used to solve the diffusion equation and an inverse solver based on this forward solver is implemented to calculate the absorption and scattering maps from the acquired data. The MR a priori information is used to guide the optical reconstruction algorithm. Phantom studies show that the absorption coefficient of a 7 mm inclusion in an irregular object located in 64 mm phantom is recovered with 11 % error when MR a priori information is used. ENU induced tumor model is used to test the performance of the system in vivo.