Hidehiro Watanabe

Bio: Hidehiro Watanabe is an academic researcher from Toshiba. The author has contributed to research in topics: Photomask & Signal. The author has an hindex of 14, co-authored 59 publications receiving 1605 citations.

A precise and fast temperature mapping using water proton chemical shift.

Abstract: A new temperature measurement procedure using phase mapping was developed that makes use of the temperature dependence of the water proton chemical shift. Highly accurate and fast measurements were obtained during phantom and in vivo experiments. In the pure water phantom experiments, an accuracy of more than +/- 0.5 degrees C was obtained within a few seconds/slice using a field echo pulse sequence (TR/TE = 115/13 ms, matrix = 128 x 128, number of slices = 5). The temperature dependence of the water proton chemical shift was found to be almost the same for different materials with a chemical composition similar to living tissues (water, glucide, protein). Using this method, the temperature change inside a cat's brain was obtained with an accuracy of more than +/- 1 degree C and an in-plane resolution of 0.6 x 0.6 mm. The temperature measurement error was affected by several factors in the living system (B0 shifts caused by position shifts of the sample, blood flow, etc.), the position shift effect being the most serious.

Stacked capacitor cells for high-density dynamic RAMs

Abstract: A novel process sequence fabricating stacked capacitor cells has been developed for high-density dynamic RAMs (random access memories). Enhanced cell capacitance can be obtained by opening the contact window for the lower electrode of the stacked capacitor after the deposition of the electrode poly-Si. This is followed by additional substrate Si etching. The procedure results in sufficient cell capacitance even in 64-Mb dynamic RAMs. >

Magnetic resonance diagnostic apparatus

Abstract: In an improved INEPT pulse sequence, an excitation pulse, a refocus pulse and an excitation pulse are sequentially applied for 1 H spins. A refocus pulse and an excitation pulse are sequentially applied for 13 C spins that are spin-spin coupled with the 1 H spins. A magnetic resonance signal is acquired from 1 H spins or 13 C spins. The second refocus pulse for 1 H is applied as a slice selective pulse at a time different from the time the first refocus pulse for 13 C is applied. This allows localization to be achieved without adversely affecting the flip angle of the first refocus pulse for 13 C.

Semiconductor memory device with stacked capacitor structure and the manufacturing method thereof

Abstract: A dynamic random access memory with a stacked capacitor cell structure is disclosed which has a memory cell provided on a silicon substrate and having a MOSFET and a capacitor. An insulative layer is formed on the substrate, and a first polycrystalline silicon layer is formed on this insulative layer. These layers are simultaneously subjected to etching and define a contact hole which penetrates them to come in contact with the surface of the source. A second polycrystalline silicon layer is formed on the first polycrystalline silicon layer to uniformly cover the inner wall of the contact hole and that surface portion of the source which is exposed through the contact hole. The first and second silicon layers are simultaneously subjected to patterning to provide the lower electrode of the capacitor. After a capacitor insulation layer is formed on the second polycrystalline silicon layer, a third polycrystalline silicon layer is formed on the capacitor insulation layer so as to bury a recess of the second polycrystalline silicon layer. The third silicon layer constitutes the upper electrode of the capacitor.

Method and apparatus for driving an ink jet head

Abstract: An ink jet head having ink chambers, energy-generating elements provided in the ink chambers, respectively, and ink outlet ports communicating with the ink chambers, respectively. The ink jet head may be left unused for a time longer than a predetermined time, with a meniscus formed in each ink outlet port. In this case, a drive pulse is applied to each energy-generating element several times, thereby forcing the ink outwards from the ink outlet port and increasing a surface area of the ink from a surface area of the meniscus. Then, a negative pressure is applied in each ink chamber, thereby drawing the ink back toward the ink chamber, thus forming a meniscus again in the ink outlet port. In this condition, a drive pulse is applied to the energy-generating element, thus ejecting an ink droplet from the ink outlet port to record data.

Nanoshell-mediated near-infrared thermal therapy of tumors under magnetic resonance guidance

Abstract: Metal nanoshells are a class of nanoparticles with tunable optical resonances. In this article, an application of this technology to thermal ablative therapy for cancer is described. By tuning the nanoshells to strongly absorb light in the near infrared, where optical transmission through tissue is optimal, a distribution of nanoshells at depth in tissue can be used to deliver a therapeutic dose of heat by using moderately low exposures of extracorporeally applied near-infrared (NIR) light. Human breast carcinoma cells incubated with nanoshells in vitro were found to have undergone photothermally induced morbidity on exposure to NIR light (820 nm, 35 W/cm2), as determined by using a fluorescent viability stain. Cells without nanoshells displayed no loss in viability after the same periods and conditions of NIR illumination. Likewise, in vivo studies under magnetic resonance guidance revealed that exposure to low doses of NIR light (820 nm, 4 W/cm2) in solid tumors treated with metal nanoshells reached average maximum temperatures capable of inducing irreversible tissue damage (DeltaT = 37.4 +/- 6.6 degrees C) within 4-6 min. Controls treated without nanoshells demonstrated significantly lower average temperatures on exposure to NIR light (DeltaT < 10 degrees C). These findings demonstrated good correlation with histological findings. Tissues heated above the thermal damage threshold displayed coagulation, cell shrinkage, and loss of nuclear staining, which are indicators of irreversible thermal damage. Control tissues appeared undamaged.

Magnetic resonance imaging device

Abstract: By using a multiple receiving coil composed of receiving coils, an imaging portion of a subject is subjected to a first pulse sequence to create n sensitivity images (701 to 703) fewer than the examination images. When these sensitivity images are created, an NMR signal is measured for only the low-frequency region of the k space. A second pulse sequence from which a phase encode step is removed is conducted to create m (m>n) examination images (704, 705) of the subject by using the receiving coils. When sensitivity distributions (707, 708) of the receiving coils are determined for the sensitivity images (701 to 703), and if there are no sensitivity distributions corresponding to the slice positions of the examination images (704, 705), they are determined by slice interpolation using the sensitivity distributions (701 to 703), and the aliasing artifacts of the examination images (704, 705) are removed by matrix operation by using the sensitivity distributions (707, 708).

Vertically-stacked, field-programmable, nonvolatile memory and method of fabrication

Abstract: A very high density field programmable memory is disclosed. An array is formed vertically above a substrate using several layers, each layer of which includes vertically fabricated memory cells. The cell in an N level array may be formed with N+1 masking steps plus masking steps needed for contacts. Maximum use of self alignment techniques minimizes photolithographic limitations. In one embodiment the peripheral circuits are formed in a silicon substrate and an N level array is fabricated above the substrate.

Noninvasive MR Imaging-Guided Focal Opening of the Blood-Brain Barrier in Rabbits

Abstract: PURPOSE: To determine if focused ultrasound beams can be used to locally open the blood-brain barrier without damage to surrounding brain tissue and if magnetic resonance (MR) imaging can be used to monitor this procedure. MATERIALS AND METHODS: The brains of 18 rabbits were sonicated (pulsed sonication) in four to six locations, with temporal peak acoustic power ranging from 0.2 to 11.5 W. Prior to each sonication, a bolus of ultrasonographic (US) contrast agent was injected into the ear vein of the rabbit. A series of fast or spoiled gradient-echo MR images were obtained during the sonications to monitor the temperature elevation and potential tissue changes. Contrast material–enhanced MR images obtained minutes after sonications and repeated 1–48 hours later were used to depict blood-brain barrier opening. Whole brain histologic evaluation was performed. RESULTS: Opening of the blood-brain barrier was confirmed with detection of MR imaging contrast agent at the targeted locations. The lowest power leve...