A radiological imaging apparatus of the present invention comprises an image pickup device and a medical examinee holding device that is provided with a bed. The image pickup device includes a large number of radiation detectors and radiation detector support plates. A large number of radiation detectors are mounted around the circumference of a through-hole and arranged in the axial direction of the through-hole. The radiation detectors are arranged in three layers formed radially with respect to the center of the through-hole and mounted on the lateral surfaces of the radiation detector support plates. Since the radiation detectors are not only arranged in the axial direction and circumferential direction of the through-hole but also arrayed in the radial direction, it is possible to obtain accurate information about a γ-ray arrival position in the radial direction of the through-hole (the positional information about a radiation detector from which a γ-ray image pickup signal is output). The use of accurate information about γ-ray arrival increases the tomogram accuracy. As a result, the present invention enhances the tomogram accuracy, that is, the PET examination accuracy.

Radiological imaging apparatus

The study of brain-computer interfaces (BCIs) has undergone 30 years of intense development and has grown into a rich and diverse field. BCIs are technologies that enable direct communication between the human brain and external devices. Conventionally, wet electrodes have been employed to obtain unprecedented sensitivity to high-temporal-resolution brain activity; recently, the growing availability of various sensors that can be used to detect high-quality brain signals in a wide range of clinical and everyday environments is being exploited. This development of biosensing neurotechnologies and the desire to implement them in real-world applications have led to the opportunity to develop augmented BCIs (ABCIs) in the upcoming decades. An ABCI is similar to a BCI in that it relies on biosensors that record signals from the brain in everyday environments; the signals are then processed in real time to monitor the behavior of the human. To use an ABCI as a mobile brain imaging technique for everyday, real-life applications, the sensors and the corresponding device must be lightweight and the equipment response time must be short. This study presents an overview of the wide range of biosensor approaches currently being applied to ABCIs, from their use in the laboratory to their application in clinical and everyday use. The basic principles of each technique are described along with examples of current applications of cutting-edge neuroscience research. In summary, we show that ABCI techniques continue to grow and evolve, incorporating new technologies and advances to address ever more complex and important neuroscience issues, with advancements that are envisioned to lead to a wide range of real-life applications.

https://ir.nctu.edu.tw:443/bitstream/11536/20522/1/000309838000041.pdf

Biosensor Technologies for Augmented Brain–Computer Interfaces in the Next Decades

This review article presents a comparative study of different silicon-based ultraviolet (UV) photodetector technologies. After a brief introduction and classification of UV photodetectors, a general comparison is made between the two most popular UV-detector solid-state materials: silicon and wide-band gap semiconductors (diamond, SiC, III-nitrides, and some III-V compounds). Particularly, the advantages of the Si-based technologies are discussed. Further in this paper, the analyses are restricted to silicon UV photodetectors. The theoretically attainable sensitivity in the UV spectral range of Si-based photodetectors is discussed. Different device structures and their working principle are shortly reviewed, followed by a comparison of the state-of-the-art Si-based UV photodetectors. By linking the device structure to the reported optical performance, the advantages and drawbacks of different structures are detailed. Finally, a number of key factors for designing high performance Si-based photodetectors are proposed.

Comparative Study of Silicon-Based Ultraviolet Photodetectors

Portable x-ray devices and methods for using such devices are described. The devices have an x-ray tube powered by an integrated power system. The x-ray tube is shielded with a low-density insulating material containing a high-Z substance. The devices can also have an integrated display component. With these components, the size and weight of the x-ray devices can be reduced and the portability of the devices enhanced. The x-ray devices also have an x-ray detecting means that is not structurally attached to the device and therefore is free standing. Consequently, the x-ray devices can also be used as a digital x-ray camera. The portable x-ray devices are especially useful for applications where portability is an important feature such as in field work, remote operations, and mobile operations such as nursing homes, home healthcare, or teaching classrooms. This portability feature can be particularly useful in multi-suite medical and dental offices where a single x-ray device can be used as a digital x­ray camera in multiple offices instead of requiring a separate device in every office.

Digital x-ray camera

Vacuum-Ultraviolet Photon Detections.

A portable X-ray unit, of a relatively light-weight, occoping a volume of less then one-half a cubic foot containing an x-ray head assembly, a unique Marx generator, a plurality of spark-gap switches and control electronics is disclosed. The Marx generator allows for the development of a relatively high voltage in excess of 100 kV, yet allows for the discharge thereof within the nanosecond range. The Marx generator is enclosed by an acrylic insulator that cooperates with an aluminum enclosure, which functions as a return current path for the capacitors in the Marx generator and also as a shield against the escape of electromagnetic radiation from the pulsed x-ray unit. The Marx generator and spark-gap switches are confined within the pressurized chamber that may contain nitrogen gas to reduce the separation of the gap in the spark-gap switches.

Mobile X-ray unit

A dual-energy x-ray system is provided which is useful in densitometry and other applications. A dual energy x-ray source, formed field emission x-ray tube driven by a Marx generator, produces a single x-ray pulse of a very short duration (e.g., 10 to 200 nanoseconds). The pulse provides x-ray energy of a first, high value early in the pulse and x-ray energy of a second, lower value later in the pulse so as to provide a dual energy level x-ray distribution comprising hard and soft x-rays. A detector system having dual x-ray energy discrimination properties, formed by soft and hard x-ray detectors and an inter-detector, receives the x-ray pulse and discriminates between the dual x-ray energy levels of the pulse.

Dual energy x-ray densitometry apparatus and method using single x-ray pulse

The efficiency and resolving power of a concave, 2400-groove/mm, blazed diffraction grating that had a Mo/Si multilayer coating were determined. The multilayer coating had a peak reflectance of 55% at 140-A near normal incidence. The efficiency of the multilayer grating for wavelengths in the 136–139-A range was 2% near normal incidence. This efficiency was a factor of 150 greater than the efficiency of a sister replica Au-coated grating in the same wavelength region. The resolving power of the multilayer-coated grating in the third order of a V viii transition with a first-order wavelength of 140.451 A was 9100. Comparisons with the Au-coated grating indicated that the application of the multilayer coating did not affect the resolving power or the blaze angle.

On-blaze operation of a Mo/Si multilayer-coated, concave diffraction grating in the 136–142-Å wavelength region and near normal incidence

A concave diffraction grating (2400 grooves/mm) coated with a Si/Mo multilayer has an efficiency of 2.5% at 290 A and a resolving power of 14,000 in third order of 156 A.

Dual-waveband operation of a multilayer-coated diffraction grating in the soft x-ray range at near-normal incidence

Responsivity of silicon photodiodes was measured from -100 C to +50 C in the 3 to 250 nm wavelength range using synchrotron and laboratory radiation sources. Two types of silicon photodiodes were studied, the AXUV series having a thin nitrided silicon dioxide surface layer and the SXUV series having a thin metal silicide surface layer. Depending on the wavelength, the responsivity increases with temperature with the rates 0.013%/C to 0.053%/C for the AXUV photodiode and 0.020%/C to 0.084%/C for the SXUV photodiode. The increase in responsivity is consistent with the decrease in the silicon bandgap energy which causes a decrease in the pair creation energy. These results are particularly important for dose measurement in extreme ultraviolet (EUV) lithography steppers and sources since the detector temperature often increases because of the high EUV intensities involved.

G. E. Holland

Papers

Mobile X-ray unit

Dual energy x-ray densitometry apparatus and method using single x-ray pulse

On-blaze operation of a Mo/Si multilayer-coated, concave diffraction grating in the 136–142-Å wavelength region and near normal incidence

Dual-waveband operation of a multilayer-coated diffraction grating in the soft x-ray range at near-normal incidence

Temperature dependence of the EUV responsivity of silicon photodiode detectors