巻号一覧
62 巻, 4 号
選択された号の論文の14件中1～14を表示しています
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巻頭言
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坂田 元道2006 年 62 巻 4 号 p. 62_4_I
発行日: 2006年
公開日: 2007/02/23
ジャーナル 認証ありPDF形式でダウンロード (23K)
第61回総会学術大会 技術活用セミナー
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坂本 肇2006 年 62 巻 4 号 p. 467-476
発行日: 2006年
公開日: 2007/02/23
ジャーナル 認証ありPDF形式でダウンロード (180K)
教育講座―技師が書く技師のための読影講座―
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石本 剛2006 年 62 巻 4 号 p. 477-490
発行日: 2006年
公開日: 2007/02/23
ジャーナル 認証ありPDF形式でダウンロード (965K)
基礎講座―医療情報の基礎から応用―
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岡崎 宣夫2006 年 62 巻 4 号 p. 491-495
発行日: 2006年
公開日: 2007/02/23
ジャーナル 認証ありPDF形式でダウンロード (376K)
臨床技術講座
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酒井 一夫2006 年 62 巻 4 号 p. 496-502
発行日: 2006年
公開日: 2007/02/23
ジャーナル 認証ありPDF形式でダウンロード (215K)
学術調査研究班報告
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熊谷 孝三, 荒木 不次男, 保科 正夫, 鬼塚 昌彦, 宗清 修三, 吉浦 隆雄, 大浦 弘樹, 橘 昌幸2006 年 62 巻 4 号 p. 503-507
発行日: 2006年
公開日: 2007/02/23
ジャーナル 認証ありPDF形式でダウンロード (66K)
JIRAトピックス
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田中 弘2006 年 62 巻 4 号 p. 508-511
発行日: 2006年
公開日: 2007/02/23
ジャーナル 認証ありPDF形式でダウンロード (44K)
論文
原著
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宮崎 功, 石崎 恵子, 小林 邦典, 加藤 匡伸2006 年 62 巻 4 号 p. 513-521
発行日: 2006年
公開日: 2007/02/23
ジャーナル フリーThe effects of imaging conditions and measures for their improvement were examined with regard to recognition of the effects of contrast on images when T1-weighted imaging with selective fat suppression was applied. Method: Luminance at the target region was examined before and after contrast imaging using phantoms assuming pre- and post-imaging conditions. A clinical examination was performed on tumors revealed by breast examination, including those surrounded by mammary gland and by fat tissue. Results: When fat suppression was used and imaging contrast was enhanced, the luminance level of fat tumors with the same structure as the prepared phantoms appeared to be high both before and after contrast imaging, and the effects of contrast were not distinguishable. This observation is attributable to the fact that the imaging conditions before and after contrast imaging were substantially different. To make a comparison between pre- and post-contrast images, it is considered necessary to perform imaging with fixed receiver gain and to apply the same imaging method for pre- and post-contrast images by adjusting post-contrast imaging conditions to those of pre-contrast imaging.抄録全体を表示PDF形式でダウンロード (235K) -
市川 勝弘, 小寺 吉衞, 大橋 一也, 杉山 雅之, 宮地 利明, 藤田 広志2006 年 62 巻 4 号 p. 522-528
発行日: 2006年
公開日: 2007/02/23
ジャーナル フリーA method of evaluating the performance of computed tomography (CT) with equivalent resolution images was investigated. Generally, in performance evaluations of CT, the resolution property is measured by the wire method, and the noise property is measured from noise images of a cylindrical water phantom. The signal-to-noise ratio (SNR) is then calculated for the integrated evaluation. Our proposed method enabled perceptual integrated evaluation by using equivalent resolution images created with frequency processing. The frequency-processing factor was calculated from the ratio of the modulation transfer factors of two models of CT, and the image of one of the two was processed by the factor. Because these processed images have resolution equivalent to images of the other CT, the perceptual evaluation with noise images becomes effective. In this investigation, images of a water phantom and a middle contrast resolution phantom were employed. Perceptual comparison of the amount of noise with equivalent resolution images could be performed easily, and effective performance evaluation was achieved. Therefore, our proposed method is useful for noise property and performance evaluation of CT.抄録全体を表示PDF形式でダウンロード (180K) -
橘 英伸, 大松 将彦, 樋口 江, 梅田 徳男2006 年 62 巻 4 号 p. 529-538
発行日: 2006年
公開日: 2007/02/23
ジャーナル フリーIt is not easy to connect a Web-based server with an existing DICOM server, and using a Web-based server on the Internet has risks. In this study, we designed and developed a secure DICOM-Network Attached Server (DICOM-NAS) through which the DICOM server in a hospital LAN was connected to the Internet. After receiving a client's image export request, the DICOM-NAS sent it to the DICOM server using the DICOM protocol. The server then provided DICOM images to the DICOM-NAS, which transferred them to the client, using HTTP. The DICOM-NAS plays an important role between the DICOM protocol and HTTP, and stores the requested images only temporarily. The DICOM server keeps all of the original DICOM images. If an unauthorized user attempts to access the DICOM-NAS, medical images cannot be accessed because images are not stored in the DICOM-NAS. Furthermore, the DICOM-NAS has features related to reporting and MPR. Therefore, the DICOM-NAS does not require a large storage capacity, but can greatly improve information security.抄録全体を表示PDF形式でダウンロード (440K) -
坂本 清, 三浦 行矣, 植田 健, 馬場 理香, 鎌倉 敏子, 坂本 理絵子, 岡部 正和, 中尾 宣夫2006 年 62 巻 4 号 p. 539-545
発行日: 2006年
公開日: 2007/02/23
ジャーナル フリーWe examined the low contrast resolution of cone beam CT (CBCT) equipped with an indirect-type flat panel detector and compared it with a commercial CT unit (Robusto). In CBCT, the X-ray tube voltage of 110 kV was used, and in the Robusto, the usual 120 kV was used for examinations. The computed tomography dose index (CTDI) of the two systems was measured, and images scanned at about the same exposure to radiation were compared. The modulation transfer factors of the two systems were measured, and the convolution kernel that was the nearest to the characteristic of CBCT was chosen among kernels of the Robusto. A water phantom with a diameter of 200 mm was scanned, Wiener spectra were calculated, and signal-to-noise ratios were compared. The low contrast resolution phantom was scanned, and detectability and contrast-to-noise ratio (CNR) were measured. In addition, we placed diluted contrast medium into a phantom, scanned the phantom, and measured the detectability and CNR. When the X-ray irradiation condition of CBCT was 75 mAs at 110 kV, the equal dose of radioactivity in the Robusto was 50 mAs at 120 kV. In the low contrast resolution phantom, detectability was 8.7%mm in CBCT, and 9.4%mm in the Robusto. In the low contrast resolution evaluation phantom, CNR was 1.39 in CBCT, and 2.69 in the Robusto. With diluted contrast medium, CNR was 1.28 in CBCT, and 0.60 in the Robusto. CBCT was inferior to the Robusto in a low contrast resolution phantom, but CBCT was superior to the Robusto using diluted contrast medium. We found that CBCT was useful in examinations using contrast media.抄録全体を表示PDF形式でダウンロード (191K) -
Norio Hayashi, Shigeru Sanada, Masayuki Suzuki, Yukihiro Matsuura, Kaz ...2006 年 62 巻 4 号 p. 546-554
発行日: 2006年
公開日: 2007/02/23
ジャーナル フリーMagnetic resonance (MR) imaging is useful for the diagnosis of brain atrophy and intracranial abnormalities. We have developed a method of automated volumetry to evaluate the degree of brain atrophy for the diagnosis of dementia. Whole-brain MR images with thin slices without gaps are required for segmentation and volumetry. However, obtaining such images requires that the patient remain at rest for a prolonged period, thereby reducing the throughput of MR imaging examinations. Therefore, a method is needed for the reconstruction of isotropic three-dimensional (3D) data using routine axial, sagittal, and coronal MR images with 30% gaps and measurement of brain volume. The method of reconstructing 3D data consists of four processes: 1) segmentation of the brain region on axial, sagittal, and coronal MR images using the region-growing technique; 2) setting data to a 3D domain; 3) registration by manual operation; and 4) interpolation between the data based on linear interpolation. In clinical MR images, the differences between this method and the conventional technique were less than 10%. These results demonstrate that this technique is able to construct 3D data from axial, sagittal, and coronal MR images.抄録全体を表示PDF形式でダウンロード (331K) -
山本 めぐみ, 石田 隆行, 川下 郁生, 影本 正之, 藤川 光一, 水戸川 芳巳, 祖母井 努, 石根 正博, 伊藤 勝陽, 秋山 實利2006 年 62 巻 4 号 p. 555-564
発行日: 2006年
公開日: 2007/02/23
ジャーナル フリーWe have developed an automated computerized method for the detection of lung nodules in three-dimensional (3D) computed tomography (CT) images obtained by helical CT. In this scheme, a lung segmentation technique for the determination of the nodule search area is performed based on a gray-level thresholding technique. To enhance lung nodules, we employed the 3D cross-correlation method by using a 3D Gaussian template with zero-surrounding as a model of lung nodule. False positives are then eliminated by using a rule-base with 53 features. For further reduction of false positives, we performed linear discriminant analysis using these 53 features. The average number of false positives was 6.7 per case at a percent sensitivity of 85.0%. This computerized scheme will be useful to radiologists by providing a “second opinion” in case of possible early lung cancer.抄録全体を表示PDF形式でダウンロード (286K) -
小倉 明夫, 前田 富美恵, 宮井 明, 林 浩二, 本郷 隆治2006 年 62 巻 4 号 p. 565-569
発行日: 2006年
公開日: 2007/02/23
ジャーナル フリーDiffusion-weighted images (DWIs) with high b-factor in the body are often used to detect and diagnose cancer at MRI. The echo planar imaging (EPI) sequence and high motion probing gradient pulse are used at diffusion weighted imaging, causing high table vibration. The purpose of this study was to assess whether the diffusion signal and apparent diffusion coefficient (ADC) values are influenced by this vibration because of time-varying magnetic fields. Two DWIs were compared. In one, phantoms were fixed on the MRI unit's table transmitting the vibration. In the other, phantoms were supported in air, in the absence of vibration. The phantoms called “solution phantoms” were made from agarose of a particular density. The phantoms called “jelly phantoms” were made from agarose that was heated. The diffusion signal and ADC value of each image were compared. The results showed that the signal of DWI units using the solution phantom was not affected by vibration. However, the signal of DWI and ADC were increased in the low-density jelly phantom as a result of vibration, causing the jelly phantom to vibrate. The DWIs of vibrating regions such as the breast maybe be subject to error. A countermeasure seems to be to support the region adequately.抄録全体を表示PDF形式でダウンロード (98K)
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