This study aims to propose a novel method for multi-beam tomosynthesis using a single-beam x-ray source based on carbon nanotubes (CNTs) and compact vacuum CNT-based x-ray tubes are arranged on a 3D hemispherical curve. The proposed method enables each member of a multi-beam x-ray gantry to face the center of the same field of view (FOV), which has potential applications in medical imaging. This study evaluates the feasibility of our proposed method and its potential advantages over existing methods.
We have designed a 160kV radiation source based on carbon nanotubes (CNT) capable of irradiating cells. The functionality of the designed system was verified by assessing the physical and chemical properties of directly synthesized CNT and the resulting x-ray dosage emitted. The conventional x-ray source widely used until now employs an analog method that generates thermal electrons through filament heating. To overcome the limitations of this existing analog method, a novel digital x-ray tube capable of instantaneously controlling power became essential. Taking these aspects into consideration, our study developed a 160kV x-ray source based on CNT, enabling digital control of x-ray energy and dosage. We anticipate that our developed source can find applications in the field of cell therapy in the future.
A stationary digital tomosynthesis system using 43 carbon nanotube (CNT) field emission X-ray sources has been developed to overcome some issues in traditional chest tomography synthesis systems using a single X-ray source. This new system utilizes CNTs to digitize X-ray source, allowing for the acquisition of high-resolution 3D X-ray images without motion blur. The system has been compared to a traditional tomosynthesis system using a thermionic source based on filament. This study reports a multi-array X-ray device, in which a body part made of an insulating material, which is a non-metallic material, provides a natural insulating environment to generate high-performance X-ray devices.
In this study, the new CNT field emitter-based X-ray sources are designed, fabricated, and developed to improve resolution compared to the filament-based X-ray sources. Also, we compare the geometric difference between two tomosynthesis systems, and it is expected to provide high-resolution 3D images for chest diagnosis in the medical field.
A multi-beam compact tomosynthesis system has been developed to acquire chest X-ray images and provide reconstructed 3D X-ray images. The system uses 43 field emission X-ray sources based on carbon nanotubes (CNTs). The CNT-based X-ray source consists of an anode array, gate array, and electron gun (e-gun) array and is stationary while the digital X-ray detector moves. To analyze 3D data of the electron emission trajectory in the multi-beam X-ray source, simulation software which is CST Particle Tracking Studio was used. In this developed system, we applied a vacuum external projection type X-ray source device. Specifically, it relates to a vacuum externally protruding type X-ray source device that can be easily replaced by protruding the lower part of the unit X-ray source to the outside of the vacuum.
In this study, we have developed the digital tomosynthesis system which is an improvement over conventional tomosynthesis systems as it is lighter, is easier to load the CNT e-gun, eliminates motion blur since the gantry is fixed, and provides fast and high-resolution images because of the reduction of the focal spot size with the use of multiple CNT-based X-ray sources.
We designed and developed a carbon nanotube (CNT)-based reflective digital cell irradiation system capable of irradiating cells. The chemical and physical properties of the CNT synthesized directly on the patterned substrate were confirmed, and the field emission characteristics with a maximum anode current of 10 mA were evaluated through the I-V curve. Also, electrostatic simulation was conducted to confirm the electric field distribution and the electron beam trajectory. According to the duty (27.3 mGy at anode on time 10 sec, duty 50 %), the anode voltage (25.2 mGy at anode on time 10 sec, duty 50 %, anode voltage 40 kV) and the distance between the window and the cell stage (anode on time 10 sec, duty 50%, anode voltage 40 kV, 19.4 mGy), the function of the system was verified by obtaining the dose emitted from the system. This study confirmed that it is suitable as the cell irradiation system for studying the radiobiological effects of low-dose radiation-irradiated cells.
When designing an X-ray monoblock for portable systems, the size and compactness of X-ray tube plays an important role. The monoblocks normally contains high voltage unit and X-ray tube immersed together inside the sea of insulating oil and sealed by Aluminum or plastic frame. Normally, mononblocks built for 100 kV or higher X-ray tube are quite bulky, not because of the high voltage source unit but because of the huge size of glass enveloped X-ray tube. The compactness of X-ray tube can decrease the size of mononblock and it can subsequently increase the portability of X-ray system. There are efforts done to decrease the size of X-ray tube by replacing the glass envelope with metal ceramic frames in CT X-ray tubes which are categorized as Rotating X-ray tubes. However, there are few or almost no researches on looking for an alternative to avoid making bulky glass X-ray tubes for Stationary tubes. It might be partially because the discovery of Xray tubes is all connected to the glass vacuum tubes. Other reasons could be due to matureness of glass making technology, which though still lacks automation but is cheaper and easier. Our group has realized that using ceramic to maintain vacuum and use it as an alternative to glass envelop can increase the robustness and compactness of filament X-ray tubes. Moreover, it can also help engineers to develop smaller and lighter monoblock for high-end X-ray systems. Thus, in this study, we report a development of compact 120 kV ceramic-based filament type X-ray tube for panoramic dental imaging. We have compared in-house built ceramic X-ray tube with commercial glass X-ray tube which is most commonly used for 100 kV panoramic dental X-ray imaging system. The result shows that despite the 38 % reduction in size, ceramic tube has better IV characteristic with similar filament size and higher limiting spatial resolution compared to glass X-ray tube. Moreover, we have successfully performed all the X-ray experiments using 100 kV 500W custom built high voltage source which can be used for making monoblocks.
In fluoroscopy, X-rays are used to obtain the real-time moving images of the human anatomy. To do so, a pulsed fluoroscopy is used so that patient and staffs are exposed to minimum radiation possible. However, in most medium priced pulsed fluoroscopy systems, X-ray tube without grid is used. The grid-less X-ray tube cannot produce perfect digital pulses due to inherent problem associated with thermionic emission of filament. Thus, the patient is exposed to unnecessary radiation using conventional Fluoroscopic system. This problem can be easily solved using carbon nanotube (CNT) based digital X-ray tubes and are much cheaper to manufacture than grid controlled filament based X-ray tubes. In this study, we have developed 120 kV CNT-based digital X-ray tubes for pulsed fluoroscopy that can be operated at very high frequency (~ MHz) producing low radiation dose during X-ray imaging. The DC and pulsed performance of Xray tube is studied, and the X-ray imaging of human skull is done with relatively low X-ray dose by pulsing the X-ray tube at 25 kHz. The commercial high voltage sources, function generator and N type-MOSFET were used for high-speed switching of E-beam during X-ray emission. This paper could help the radiologists and all the medical personnel understand the advantages of CNT based X-ray technology over filament for X-ray imaging use low dose radiation.
KEYWORDS: Radiation effects, Beryllium, 3D modeling, Scanning electron microscopy, Radiation oncology, Radiotherapy, Particles, Metals, Medicine, Medical research
Radiation research primarily aims to improve radiation therapy and the use of radiation on soft materials. There are many reports available on the effects of high-dose radiation on cells, but the effects of low-dose radiation still require much scientific evidence. Therefore, we intend to study the effects of low-dose irradiation on cell internal structures by cold cathode field emission carbon nanotube (CNT)-based cell irradiator. Hence, we designed a CNT-based microbeam system to irradiate cells. CNT emitter was fabricated by synthesizing CNTs on point shaped substrate. The growth of CNTs was confirmed by scanning electron microscope (SEM). The aging process was carried out to improve the performance of the CNT emitter and the I-V characteristic was measured. We also conducted the simulation study in order to confirm the electric field change and the electron beam trajectory.
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