Synthetic approaches towards [18F]fluoro-DOG1, a potential radiotracer for the imaging of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GIST) can currently only be identified by invasive biopsy sampling followed by immunohistochemical analysis. It would however be highly advantageous to have a radioligand able to bind the calcium-activated chloride channel DOG1, which is specific for GIST, and thus enable the sensitive, non-invasive and specific functional imaging of the disease by Positron Emission Tomography (PET). For this purpose, we developed different synthetic strategies towards a 4-phenylthiazole-2-amine-based labeling precursor that can be directly reacted with ¹⁸F-fluoride to yield a radiotracer intended to bind DOG1. Of these, a boronic acid pinacol ester radiolabeling precursor could be efficiently reacted with ¹⁸F in a one-step reaction, and the target radioligand [¹⁸F]fluoro-DOG1 be obtained in radiochemical yields of 34.0?±?11.1% within 85?min overall synthesis time.     

光学相干层析成像色散补偿研究

针对通过增加光源谱宽度来提高光学相干层析成像系统分辨率时样品色散特性的限制作用,分析了色散与光学相干层析成像系统纵向光程分辨率的约束关系.根据物质色散特性,采用数值变换方法对光学相干层析成像相干成像信号进行了色散补偿.实验使用了中心波长1 550 nm 自激发辐射光源和光纤迈克尓逊干涉结构,对水和光学快速扫描延迟线引入的二阶和三阶色散进行了数值补偿并通过相位修正因子来改善补偿效果.确定了一种普适的、快速的数值色散补偿方法.在对水中盖玻片和生物组织和的光学相干层析成像图像的色散补偿实验中取得了良好的效果,证明了方法的可行性.     

STATIC REGIME IMAGING OF LOCATIONS OF CERTAIN 3D ELECTROMAGNETIC IMPERFECTIONS FROM A BOUNDARY PERTURBATION FORMULA

We are concerned, in a static regime, with a three-dimensional bounded domain of certain an imaging approach of the locations in electromagnetic imperfections. This approach is related to Electrical Impedance Tomography and makes use of a new perturbation formula in the electric fields. We present two localization procedures, from a Current Pro- jection method that deals with the single imperfection context and an inverse Fourier process that is devoted to multiple imperfections configurations. These procedures extend those that were described in our previous work, since operating for a broader class of settings. Namely, the localization is additionally performed for certain purely electric imperfections, as established from numerical simulations.     

X光Gabor波带片编码成像技术实验研究

 基于星光II实验装置进行了Gabor波带片编码成像探索性实验研究。采用束匀滑光斑三倍频激光打靶，辐照专门设计的ＣＨ埋金属条靶（共两种），产生了有明确形状、边缘清晰的等离子体。研制了专门的Gabor波带片编码相机，并利用该相机采用单张胶片对不同的靶目标在不同的深度层次上曝光的技术，获得了具有深度层次信息的三维激光等离子体编码像。利用数值重建技术对实验所获得的图像解码，最终获得了在不同深度层次上的激光等离子体信息。     

Variable tomographic scanning with wavelength scanning digital interference holography

We present a new method for variable tomographic scanning based on the wavelength scanning digital interference holography (WSDIH). A series of holograms are generated with a range of scanned wavelengths. The object field is reconstructed in a number of selected tilted planes from each hologram, and the numerical superposition of all the tilted object fields results in a variable tomographic scanning. The scanning direction can be arbitrary angles in 3D space but not limited in a 2D plane, thus the proposed algorithm offers more flexibility for acquiring and observing randomly orientated features of a specimen in a WSDIH system. Experiments are performed to demonstrate the effectiveness of the method.     

Limited projections laser speckle tomography of complex flows

Different approaches are discussed applied to reconstruction of local flow parameters using line-of-sight laser probing. The first one is based on single projection measurement and detailed numerical simulation of flow pattern. The second one is based on multi-projectional line-of-sight measurement and reconstructing local flow parameters by solving inverse integral transforms. Holographic interferometry (HI) and speckle photography (SP) are used for laser probing of complex 3D media under study. Computer-assisted tomography (CAT) approach based on Radon integral transform is described and examples of reconstructed flowfields are given including compressible flows with shock waves. Statistical information about flow studied is extracted as well, and maps of local statistical turbulence parameters are quantitatively determined by using obtained SP-data and a new Erbeck–Merzkirch integral transform.     

Minimax estimation of the Wigner function in quantum homodyne tomography with ideal detectors

We estimate the quantum state of a light beam from results of quantum homodyne measurements performed on identically prepared pulses. The state is represented through the Wigner function, a “quasi-probability density” on ℝ² which may take negative values and must satisfy intrinsic positivity constraints imposed by quantum physics. The data consists of n i.i.d. observations from a probability density equal to the Radon transform of the Wigner function. We construct an estimator for the Wigner function and prove that it is minimax efficient for the pointwise risk over a class of infinitely differentiable functions. A similar result was previously derived by Cavalier in the context of positron emission tomography. Our work extends this result to the space of smooth Wigner functions, which is the relevant parameter space for quantum homodyne tomography.      

Infrared species limited data tomography through Tikhonov reconstruction

Optical tomography based on infrared laser light absorption is a promising approach for making spatially- and temporally-resolved fuel concentration measurements within combustion devices, but limited optical access often restricts both the number of laser beams and their arrangement. This paper demonstrates how Tikhonov regularization based on a Laplacian smoothing matrix can solve the resulting limited data tomography problem, and provides superior reconstructions for Gaussian phantoms compared to modified Landweber reconstruction.     

网格基任向偏导实现及层析应用

将光线偏折方程中的任向偏导转化为数值差分形式,并应用于层析线性运算.网格化待测场,将微分待测场的每一正方形网格及相应折射率近似为曲面底的正圆锥体,圆锥体顶端的折射率值对应该网格的折射率,在底面的投影对应网格的中心.假设紧邻三网格中心间的折射率分布共平面,在一个网格宽度内将偏导转化成数值差分形式.结果发现：基于上述近似和假设,可以将任意探测光线相关的偏导转化为数值差分形式,将非线性偏导方程转化为线性差分方程,建立层析方程.于是,偏折角可以作为投影直接重建.