Kazuhiro Kido

X-ray phase imaging: from synchrotron to hospital.

With the aim of clinical applications of X-ray phase imaging based on Talbot–Lau-type grating interferometry to joint diseases and breast cancer, machines employing a conventional X-ray generator have been developed and installed in hospitals. The machine operation especially for diagnosing rheumatoid arthritis is described, which relies on the fact that cartilage in finger joints can be depicted with a dose of several milligray. The palm of a volunteer observed with 19 s exposure (total scan time: 32 s) is reported with a depicted cartilage feature in joints. This machine is now dedicated for clinical research with patients.

Cadaveric and in vivo human joint imaging based on differential phase contrast by X-ray Talbot-Lau interferometry.

We developed an X-ray phase imaging system based on Talbot-Lau interferometry and studied its feasibility for clinical diagnoses of joint diseases. The system consists of three X-ray gratings, a conventional X-ray tube, an object holder, an X-ray image sensor, and a computer for image processing. The joints of human cadavers and healthy volunteers were imaged, and the results indicated sufficient sensitivity to cartilage, suggesting medical significance.

Bone cartilage imaging with x-ray interferometry using a practical x-ray tube

The purpose of this study was to design an X-ray Talbot-Lau interferometer for the imaging of bone cartilage using a practical X-ray tube and to develop that imaging system for clinical use. Wave-optics simulation was performed to design the interferometer with a practical X-ray tube, a source grating, two X-ray gratings, and an X-ray detector. An imaging system was created based on the results of the simulation. The specifications were as follows: the focal spot size was 0.3 mm of an X-ray tube with a tungsten anode (Toshiba, Tokyo, Japan). The tube voltage was set at 40 kVp with an additive aluminum filter, and the mean energy was 31 keV. The pixel size of the X-ray detector, a Condor 486 (Fairchild Imaging, California, USA), was 15 μm. The second grating was a Ronchi-type grating whose pitch was 5.3 μm. Imaging performance of the system was examined with X-ray doses of 0.5, 3 and 9 mGy so that the bone cartilage of a chicken wing was clearly depicted with X-ray doses of 3 and 9 mGy. This was consistent with the simulations predictions. The results suggest that X-ray Talbot-Lau interferometry would be a promising tool in detecting soft tissues in the human body such as bone cartilage for the X-ray image diagnosis of rheumatoid arthritis. Further optimization of the system will follow to reduce the X-ray dose for clinical use.

Development of the Talbot-Lau interferometry system available for clinical use

The prototype of the Talbot-Lau interferometer for clinical use was designed and applied to the preclinical examination. The human cadaveric hand and the mastectomy specimen were imaged. As a result, the images obtained by Talbot-Lau interferometry sensitively depicted the cartilages or the intraductal carcinoma. This result indicated that the Talbot-Lau interferometry would be a promising technology of the image diagnosis.

Application of X-ray grating interferometry for the imaging of joint structures

Abstract Conventional X-ray absorption contrast imaging does not depict soft tissues, such as cartilage, in sufficient detail. For visualization of the soft tissues, X-ray phase-contrast imaging is more sensitive than absorption-contrast imaging. The basic concept of the X-ray phase-contrast imaging used in this study is similar to that of differential interference contrast (Nomarski) microscopy. We applied Talbot–Lau X-ray interferometry to visualize the joint structures in the right hand and knee of a donated cadaver. This imaging system simultaneously produced three different types of images: an absorption image, a differential phase image, and a visibility image. The interface between the articular cartilage of the metacarpo-phalangeal joint and fluid or the bony cortex was clearly demonstrated on the differential phase image, whereas this interface was unclear on the absorption image. Within the knee joint, the surface of the articular cartilage was demonstrated both on the differential phase and visibility images; the medial collateral ligament and medial meniscus were also visualized successfully. These results are clinically significant for the diagnosis and therapeutic estimation of rheumatoid arthritis and related joint diseases. This feasibility study on the clinical application of this imaging tool was a collaborative effort of researchers in the fields of physics, radiology, and gross anatomy.

Development of X‐Ray Talbot‐Lau Interferometer with a Practical X‐Ray Tube for Medical Imaging

The purpose of this study was to design an X‐ray Talbot‐Lau interferometer for the imaging of bone cartilage using a practical X‐ray tube and to develop that imaging system for clinical use. Wave‐optics simulation was performed to design the interferometer with a practical X‐ray tube, a source grating, two X‐ray gratings, and an X‐ray detector. An imaging system was created based on the results of the simulation. The specifications were as follows: the focal spot size was 0.3 mm of an X‐ray tube with a tungsten anode. The tube voltage was set at 40 kVp with an additive aluminum filter. The pixel size of the X‐ray detector was 85 μm. The amplitude grating was a Ronchi‐type grating whose pitch was 5.3 μm. Imaging performance of the system was examined with X‐ray doses of 0.5, 1 and 3 mGy so that the bone cartilage of a chicken wing was clearly depicted with X‐ray doses of 3 mGy. This was consistent with the simulation’s predictions. Further optimization of the system will follow to reduce the X‐ray dose for...