著者

村瀬 研也

出版者

公益社団法人 日本医学物理学会

雑誌

医学物理 (ISSN:13455354)

巻号頁・発行日

vol.36, no.1, pp.55-61, 2016-05-31 (Released:2016-11-30)

参考文献数

16

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Partial differential equations are often used in the field of medical physics. In this (final) issue, the methods for solving the partial differential equations were introduced, which include separation of variables, integral transform (Fourier and Fourier-sine transforms), Green's function, and series expansion methods. Some examples were also introduced, in which the integral transform and Green's function methods were applied to solving Pennes' bioheat transfer equation and the Fourier series expansion method was applied to Navier-Stokes equation for analyzing the wall shear stress in blood vessels.Finally, the author hopes that this series will be helpful for people who engage in medical physics.

著者

高橋 康幸 五十嵐 博 平野 邦弘 河原田 泰尋 五十嵐 均 村瀬 研也 望月 輝一

出版者

公益社団法人 日本放射線技術学会

雑誌

日本放射線技術学会雑誌 (ISSN:03694305)

巻号頁・発行日

vol.63, no.3, pp.335-340, 2007-03-20 (Released:2007-04-05)

参考文献数

9

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An amendment concerning the enforcement of the law on the prevention of radiation hazards due to radioisotopes, etc., and the medical service law enforcement regulations were promulgated on June 1, 2005. This amendment concerned international basic safety standards and the sealing of radiation sources. Sealed radiation sources ≤3.7 MBq, which had been excluded from regulation, were newly included as an object of regulation. Investigation of the SPECT system instituted in hospitals indicated that almost all institutions adhere to the new amendment, and the calibration source, the checking source, etc., corresponding to this amendment were maintained appropriately. Any institutions planning to return sealed radioisotopes should refer to this report.

著者

村瀬 研也

出版者

医用画像情報学会

雑誌

医用画像情報学会雑誌 (ISSN:09101543)

巻号頁・発行日

vol.34, no.3, pp.112-119, 2017-09-30 (Released:2017-10-06)

参考文献数

30

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Nanomedicine is the medical application of nanotechnology. Nanomedicine ranges from the medical applications of nanomaterials and biological devices, to nanoelectronic biosensors, and even possible future applications of molecular nanotechnology such as biological machines. In 2005, a new imaging method called magnetic particle imaging (MPI)was introduced. MPI can visualize the spatial distribution of magnetic nanoparticles(MNPs)with high sensitivity, spatial resolution, and imaging speed. MPI uses the nonlinear response of MNPs to detect their presence in an alternating magnetic field(AMF). MNPs can induce heat under an AMF, which allows applications to hyperthermia(magnetic hyperthermia). This paper describes the principle of MPI and applications to nanomedicine including the quantification of pulmonary mucociliary clearance, the prediction of therapeutic effects of magnetic hyperthermia, the monitoring of magnetic targeting, and cellular imaging and tracking for regenerative medicine. The future perspective of MPI is also described.

著者

村瀬 研也 近江 雅人 木村 敦臣

出版者

大阪大学

雑誌

挑戦的萌芽研究

巻号頁・発行日

2015-04-01

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近年、磁性ナノ粒子(MNP)を内包した薬剤を外部磁場を用いて目的の場所に送達する磁気送達法や外部から交番磁場を印加して癌細胞を死滅させる磁気温熱療法が注目されている。これらの治療法の有効性を高めるためには、集積したMNPの空間分布を可視化し、集積量を正確に定量する必要がある。最近、我々はMNPを画像化する磁気粒子イメージング(MPI)法およびその装置を開発した。そこで、我々のMPI法を用いて磁気送達や磁気温熱療法の効果を最適化するシステムを開発し、その有用性をファントムや動物実験によって検討した。その結果、開発したシステムは磁気送達や磁気温熱療法の最適化に有用であることが示唆された。

著者

山田 幸子 上口 貴志 尾方 俊至 荻原 良太 村瀬 研也

出版者

公益社団法人 日本医学物理学会

雑誌

医学物理 (ISSN:13455354)

巻号頁・発行日

vol.34, no.2, pp.35-46, 2014 (Released:2015-03-06)

参考文献数

19

被引用文献数

1

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An iterative reconstruction (IR) technique in computed tomography (CT) is expected to play an important role in reducing the radiation dose while preserving both spatial resolution and contrast-to-noise ratio. However, images obtained by using the IR technique are known to have different visual appearances from those obtained by using the traditional filtered back-projection (FBP) reconstruction. This appearance is often figuratively described as “blocky,” but it has not been objectively characterized further. In this paper, we propose a novel image quality metric, called “perceptual image dissimilarity” (PID), to characterize the visual dissimilarity between FBP and IR images. The PID was formulated as a grayscale transformation and subsequent structural similarity (SSIM)-based image quality measurement. The PID metric was validated using phantom images with three different modules. Sixty datasets, each consisting of an IR image and its corresponding noise-level-equivalent FBP image, were visually assigned “subjective dissimilarity scores” on a five level scale by six observers. The data sets were then quantitatively analyzed using both the PID and the traditional mean squared error (MSE) metrics. Our results show that the PID is highly consistent with the subjective dissimilarity score and thus delivers superior performance, whereas the MSE fails to quantify the observers’ visual perception.

著者

村瀬 研也

出版者

公益社団法人 日本医学物理学会

雑誌

医学物理 (ISSN:13455354)

巻号頁・発行日

vol.35, no.4, pp.297-306, 2016 (Released:2016-08-31)

参考文献数

11

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In this issue, simultaneous differential equations were introduced. These differential equations are often used in the field of medical physics. The methods for solving them were also introduced, which include Laplace transform and matrix methods. Some examples were also introduced, in which Laplace transform and matrix methods were applied to solving simultaneous differential equations derived from a three-compartment kinetic model for analyzing the glucose metabolism in tissues and Bloch equations for describing the behavior of the macroscopic magnetization in magnetic resonance imaging.In the next (final) issue, partial differential equations and various methods for solving them will be introduced together with some examples in medical physics.

著者

村瀬 研也

出版者

公益社団法人 日本医学物理学会

雑誌

医学物理 (ISSN:13455354)

巻号頁・発行日

vol.34, no.4, pp.227-235, 2015 (Released:2015-12-16)

参考文献数

8

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Utilization of differential equations and methods for solving them in medical physics are presented. First, the basic concept and the kinds of differential equations were overviewed. Second, separable differential equations and well-known first-order and second-order differential equations were introduced, and the methods for solving them were described together with several examples.In the next issue, the symbolic and series expansion methods for solving differential equations will be mainly introduced.

著者

村瀬 研也

出版者

公益社団法人 日本医学物理学会

雑誌

医学物理 (ISSN:13455354)

巻号頁・発行日

vol.35, no.1, pp.49-58, 2015 (Released:2016-01-31)

参考文献数

11

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In this issue, symbolic methods for solving differential equations were firstly introduced. Of the symbolic methods, Laplace transform method was also introduced together with some examples, in which this method was applied to solving the differential equations derived from a two-compartment kinetic model and an equivalent circuit model for membrane potential. Second, series expansion methods for solving differential equations were introduced together with some examples, in which these methods were used to solve Bessel’s and Legendre’s differential equations.In the next issue, simultaneous differential equations and various methods for solving these differential equations will be introduced together with some examples in medical physics.

著者

石根 正博 河村 正 小泉 満 伊東 久雄 村瀬 研也 稲月 伸一 飯尾 篤 浜本 研 イシネ マサヒロ カワムラ マサシ コイズミ ミツル イトウ ヒサオ ムラセ ケンヤ イナツキ シンイチ イイオ アツシ ハマモト ケン Ishine Masahiro Kawamura Masashi Koizumi Mitsuru Itoh Hisao Murase Kenya Inatsuki Shinichi Iio Atsushi Hamamoto Ken

出版者

日本医学放射線学会

雑誌

日本医学放射線学会雑誌 (ISSN:00480428)

巻号頁・発行日

vol.42, no.4, pp.p389-397, 1982-04

著者

村瀬 研也 棚田 修二 浜本 研

出版者

日本アイソト-プ協会

雑誌

Radioisotopes (ISSN:00338303)

巻号頁・発行日

vol.45, no.8, pp.491-499, 1996-08

被引用文献数

2

著者

高木 昭浩 吉岡 克則 寺岡 悟見 相馬 努 矢野 今朝人 宮坂 正 横井 孝司 村瀬 研也

出版者

公益社団法人日本放射線技術学会

雑誌

日本放射線技術學會雜誌 (ISSN:03694305)

巻号頁・発行日

vol.62, no.5, pp.729-733, 2006-05-20

被引用文献数

6 6

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The following process conventionally has been followed to develop quantitative images of cerebral blood flow: (1) mean cerebral blood flow (mCBF) is calculated by the Patlak plot method; (2) a SPECT slice that includes the basal ganglia is selected; and (3) based on the value of mCBF calculated by the Patlak plot method, the SPECT slice is corrected by the Lassen method and developed into a SPECT image of quantitative regional cerebral blood flow. However, this process is complicated, and the values of rCBF have been reported to fluctuate because selection of the SPECT slice and the ROI setting are in the hands of the operator. We have developed new software that automates this analysis. This software enables automatic processing simply by inputting the value of mCBF in the normal hemisphere. Since there is no need for manual operations such as setting the ROI, reproducibility is improved as well. Regional cerebral blood flow as determined by this software is quite similar to that calculated by the conventional method, so the existing clinical evaluation does not need to be changed. This software is considered to be useful.