Eiko Hashimoto

Attempt at Visualizing Breast Cancer with X-ray Dark Field Imaging

X-ray dark-field imaging (DFI) can clearly visualize breast cancer phantoms and cancer cell nests, stroma, fat tissue, ductus lactiferi, muscle, collagen fibers at stroma and calcification in a 2.8-mm-thick breast cancer pathological specimen. The system comprises a Bragg asymmetric-cut monochro-collimator and a 2.124-mm-thick Si 440 Laue diffraction analyzer at 35 keV. Both optical elements are Floating Zone made silicon crystals. The view size of 33 mm (H) ×19.5 mm (V) and the spatial resolution of 10 µm or better are obtainable at the vertical wiggler beamline BL14B at the Photon Factory.

3-D reconstruction and virtual ductoscopy of high-grade ductal carcinoma in situ of the breast with casting type calcifications using refraction-based X-ray CT

Stereomicroscopic observations of thick sections, or three-dimensional (3-D) reconstructions from serial sections, have provided insights into histopathology. However, they generally require time-consuming and laborious procedures. Recently, we have developed a new algorithm for refraction-based X-ray computed tomography (CT). The aim of this study is to apply this emerging technology to visualize the 3-D structure of a high-grade ductal carcinomas in situ (DCIS) of the breast. The high-resolution two-dimensional images of the refraction-based CT were validated by comparing them with the sequential histological sections. Without adding any contrast medium, the new CT showed strong contrast and was able to depict the non-calcified fine structures such as duct walls and intraductal carcinoma itself, both of which were barely visible in a conventional absorption-based CT. 3-D reconstruction and virtual endoscopy revealed that the high-grade DCIS was located within the dichotomatous branches of the ducts. Multiple calcifications occurred in the necrotic core of the continuous DCIS, resulting in linear and branching (casting type) calcifications, a hallmark of high-grade DCIS on mammograms. In conclusion, refraction-based X-ray CT approaches the low-power light microscopic view of the histological sections. It provides high quality slice data for 3-D reconstruction and virtual ductosocpy.

Hard-x-ray region tomographic reconstruction of the refractive-index gradient vector field : imaging principles and comparisons with diffraction-enhanced-imaging-based computed tomography

The unique tomographic imaging method based on refractive effects that was recently developed by Maksimenko et al. [Appl. Phys. Lett. 86, 124105 (2005)] exhibits an excellent imaging property in the hard-x-ray region for phase objects such as soft materials and biological samples. However, there seems to have been little consideration of the physical aspects of the underlying imaging principles. Also, as the method is similar to diffraction-enhanced-imaging (DEI)-based computed tomography (CT), the difference between these two methodologies has not been made clear. We theoretically consider the imaging principles starting from the measurement process to the reconstruction procedures from the viewpoint of geometrical optics and then clarify their difference in relationship to the physical quantities to be depicted. The major feature of this novel method is the in-plane two-dimensional vector-field reconstruction of the refractive-index gradient in an object, while DEI CT obtains the out-of-plane scalar-field gradient component. In other words, the novel method and DEI CT present the transverse and the longitudinal components, respectively, of the three-dimensional vector fields of the gradient refractive index. Therefore they can be considered complementary to each other.

Refraction-based tomosynthesis: Proof of the concept

Tomosynthesis is a well known technique for imaging a plane in a target by blurring other planes in the target. Commonly, the tomosynthesis is based on the x-ray absorption contrast. Recently, methods for generating other x-ray contrasts were developed. One of them, the so-called refraction contrast, is extremely sensitive to soft tissues and small defects. It was used as the base for the computed tomography. However, a very promising application of this contrast in the tomosynthesis remains undeveloped. This letter is dedicated to this problem. It includes both theoretical background and experimental implementation of the idea.

Possibility of Computed Tomographic Reconstruction of Cracks from X-ray Refraction Contrast

In recent years, X-ray refraction contrast has become a very powerful tool for nondestructive observations. It has great advantages over conventional absorption and phase-shift contrasts. The main advantage is the ability to visualize very tiny details such as cracks that are invisible in other contrasts. Therefore, the computed tomographic reconstruction from the refraction contrast is expected to have the same advantages. Here, we present the results of the refraction-based reconstruction which confirm these expectations. The structure of the sample containing cracks of submicron size was reconstructed. The cracks were proved to be clearly seen in the reconstructed images. Both 2D and 3D pictures of the reconstructed cracks are presented.

Characteristics of the fundamental FEL and the higher harmonic generation at LEBRA

Abstract The FEL system of Laboratory for Electron Beam Research and Application (LEBRA) at Nihon University has provided relatively high FEL gain around 10% at the wavelength of 1.5 μm . The numerical estimation of the FEL gain suggests that LEBRA-FEL system has a sufficient performance on the electron beam bunching. In addition, the amplification of the third harmonics accompanying the intense fundamental FEL has been observed and the spectra of which have been measured. The experimental result indicates that the phenomenon is a kind of nonlinear harmonic generation.

Refraction-based 2D, 2.5D and 3D medical imaging: Stepping forward to a clinical trial

An attempt at refraction-based 2D, 2.5D and 3D X-ray imaging of articular cartilage and breast carcinoma is reported. We are developing very high contrast X-ray 2D imaging with XDFI (X-ray dark-field imaging), X-ray CT whose data are acquired by DEI (diffraction-enhanced imaging) and tomosynthesis due to refraction contrast. 2D and 2.5D images were taken with nuclear plates or with X-ray films. Microcalcification of breast cancer and articular cartilage are clearly visible. 3D data were taken with an X-ray sensitive CCD camera. The 3D image was successfully reconstructed by the use of an algorithm newly made by our group. This shows a distinctive internal structure of a ductus lactiferi (milk duct) that contains inner wall, intraductal carcinoma and multifocal calcification in the necrotic core of the continuous DCIS (ductal carcinoma in situ). Furthermore consideration of clinical applications of these contrasts made us to try tomosynthesis. This attempt was satisfactory from the view point of articular cartilage image quality and the skin radiation dose.

First Application of X-ray Refraction-based Computed Tomography to a Biomedical Object

Abstract We have developed X-ray refraction-based computed tomography (CT) that is able to visualize soft tissue in between hard tissue. The experimental system consists of Si(220) diffraction double-crystals and is called the DEI (diffraction-enhanced imaging) method, in which the object is located between the crystals and a CCD camera to acquire data as 360 X-ray images. The X-ray energy used was 17.5 keV. The algorithm used to reconstruct CT images was developed by A. Maksimenko and colleagues. We successfully visualized articular cartilage and the distribution of bone marrow, which are inner structures. Our method has much higher contrast compared to the conventional absorption-based CT system.

Application of x-ray computed tomography based on the refraction contrast to biomedicine

We have developed X-ray refraction based computed tomography (CT) which is able to visualize soft tissue in between hard tissue. The experimental system consists of Si(220) diffraction double-crystals called the DEI (diffraction-enhanced imaging) method, object locating in between them and a CCD camera to acquire data of 900 x-ray images. The x-ray energy used was 17.5 keV. The algorithm used to reconstruct CT images has been invented by A. Maksimenko et al.. We successfully visualized calcification and distribution of breast cancer nest which are the inner structure. It has much higher contrast which in comparison with the conventional absorption based CT system.

2D and 3D Refraction Based X‐ray Imaging Suitable for Clinical and Pathological Diagnosis

The first observation of micro papillary (MP) breast cancer by x‐ray dark‐field imaging (XDFI) and the first observation of the 3D x‐ray internal structure of another breast cancer, ductal carcinoma in‐situ (DCIS), are reported. The specimen size for the sheet‐shaped MP was 26 mm × 22 mm × 2.8 mm, and that for the rod‐shaped DCIS was 3.6 mm in diameter and 4.7 mm in height. The experiment was performed at the Photon Factory, KEK: High Energy Accelerator Research Organization. We achieved a high‐contrast x‐ray image by adopting a thickness‐controlled transmission‐type angular analyzer that allows only refraction components from the object for 2D imaging. This provides a high‐contrast image of cancer‐cell nests, cancer cells and stroma. For x‐ray 3D imaging, a new algorithm due to the refraction for x‐ray CT was created. The angular information was acquired by x‐ray optics diffraction‐enhanced imaging (DEI). The number of data was 900 for each reconstruction. A reconstructed CT image may include ductus lact...