巻号一覧
66 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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浅田 恭生2010 年 66 巻 4 号 p. 66_4_I
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル 認証ありPDF形式でダウンロード (254K)
原著
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浜口 直子, 小寺 秀一2010 年 66 巻 4 号 p. 313-321
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル フリーIt is a fact that image noise influences for image qualities of the brain CT are known widely. The same principle applies to 3D-CTA, image noise significantly influences the depiction of blood vessels. So we evaluated the use of CT-AEC for 3D-CTA to optimize the scan dose and control the depiction of cerebral vessels by CT-AEC. We decided to optimize the noise index (NI) for cerebral 3D-CTA through the use of an imitation blood phantom. In the evaluation of the depiction of the anterior choroidal artery that was able to be confirmed with DSA, the detection rate in high resolution mode: NI 6.0 was 70%. The depiction of the anterior choroidal artery became defective in the detailed exam mode: NI 7.0, low dose mode: NI 9.0 because of the noise. As for the existence of cerebral aneurysms, the sensitivities were 100% with DSA and 94.3% with 3D-CTA in detailed exam mode, and there was no statistical difference. The specificities of 3D-CTA had lowered to 92.6% and 97.2% in DSA. In low dose mode and detailed exam mode, DLP had decreased by 55.2% and 18.1% on the average compared to a fixed tube current (P<0.05). However, in high resolution mode, DLP increased by 5.9% on the average. It was necessary to limit the scan range to the region of interest when we used a fixed tube current. This clinical research verified that CT-AEC on cerebral 3D-CTA was useful for dose reduction and control of the depiction ability for inspection purposes.抄録全体を表示PDF形式でダウンロード (632K) -
中口 裕二, 荒木 不次男, 丸山 雅人, 福田 正悟2010 年 66 巻 4 号 p. 322-333
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル フリーThe purpose of this study was to compare dose distributions from three different RTPS with those from Monte Carlo (MC) calculations and measurements, in heterogeneous phantoms for photon beams. This study used four algorithms for RTPS: AAA (analytical anisotropic algorithm) implemented in the Eclipse (Varian Medical Systems) treatment planning system, CC (collapsed cone) superposition from the Pinnacle (Philips), and MGS (multigrid superposition) and FFT (fast Fourier transform) convolution from XiO (CMS). The dose distributions from these algorithms were compared with those from MC and measurements in a set of heterogeneous phantoms. Eclipse/AAA underestimated the dose inside the lung region for low energies of 4 and 6 MV. This is because Eclipse/AAA do not adequately account for a scaling of the spread of the pencil (lateral electron transport) based on changes in the electron density at low photon energies. The dose distributions from Pinnacle/CC and XiO/MGS almost agree with those of MC and measurements at low photon energies, but increase errors at high energy of 15 MV, especially for a small field of 3×3 cm2. The FFT convolution extremely overestimated the dose inside the lung slab compared to MC. The dose distributions from the superposition algorithms almost agree with those from MC as well as measured values at 4 and 6 MV. The dose errors for Eclipse/AAA are lager in lung model phantoms for 4 and 6 MV. It is necessary to use the algorithms comparable to superposition for accuracy of dose calculations in heterogeneous regions.抄録全体を表示PDF形式でダウンロード (1380K) -
古屋 研, 南部 敦史, 中村 公二, 渡辺 梨恵, 野方 容子, 小宮山 貴史, 荒木 力2010 年 66 巻 4 号 p. 334-342
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル フリーWe examined the optimum conditions for pediatric brain CT scans. CT controls the X-ray transit dose using tube current alteration called automatic exposure control (AEC) to adjust the standard deviation (SD) value for each scanning region, and it also reduces exposure. If the SD value is inappropriate, children may be exposed to increased radiation. Therefore we acquired images of 500 children from the server, and examined the most suitable SD value for each age using the data of their SD value and age. X-ray transit control with AEC was influenced by scan position and the age of a child. We enabled accurate scanning and decreased radiation exposure by adjusting AEC to the age and the cephalic volume of each child. As a result, reduction of the X-ray exposure by up to 31.2% per slice in tube current alteration was possible using a suitable SD value for each age. On the other hand, it was possible to reduce X-ray exposure by up to 67.9% per slice with the scan technique that used age and corrected cephalic volume without adjusting AEC. Using the tube current alteration protocol for each age with the data of the SD value or cephalic volume in CT, we can more easily conduct scans of children under optimal conditions.抄録全体を表示PDF形式でダウンロード (565K) -
相澤 光博, 西川 慶一, 佐々木 啓太, 小林 紀雄, 山 満, 柿澤 卓, 佐野 司, 村上 伸一2010 年 66 巻 4 号 p. 343-352
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル フリーCT is an effective tool for image diagnosis because it enables noninvasive observation of internal organs. In the course of CT, 3D-CT, such as a helical scanning CT and a multi-detector row CT, has been developed. With the use of 3D-CT, organs can be observed from several viewing directions. Even now, however, 3D-CT images are generated by manual procedures to extract objective organs using the threshold method. These procedures waste time and effort. Therefore, development of highly automated and effective extracting techniques has been desired. The region growing (RG) method is one of the effective techniques of extracting internal organs. The conventional RG method, however, has some defects. Extracted regions are strongly affected by the threshold value for segmentation. A break point on a region contour yields a leakage of region. To overcome these defects, we formulated a modified region growing method with edge detection (MRGWED) which combines a three-dimensional region growing technique and an edge detection technique. Using the MRGWED, we tried to extract teeth from dentomaxillofacial 3D-CT image data.抄録全体を表示PDF形式でダウンロード (919K) -
堀 大輔, 桂川 茂彦, 村上 龍次, 平井 俊範2010 年 66 巻 4 号 p. 353-362
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル フリーWe propose a computerized method for semi-automated segmentation of the gross tumor volume (GTV) of a glioblastoma multiforme (GBM) on brain MR images for radiotherapy planning (RTP). Three-dimensional (3D) MR images of 28 cases with a GBM were used in this study. First, a sphere volume of interest (VOI) including the GBM was selected by clicking a part of the GBM region in the 3D image. Then, the sphere VOI was transformed to a two-dimensional (2D) image by use of a spiral-scanning technique. We employed active contour models (ACM) to delineate an optimal outline of the GBM in the transformed 2D image. After inverse transform of the optimal outline to the 3D space, a morphological filter was applied to smooth the shape of the 3D segmented region. For evaluation of our computerized method, we compared the computer output with manually segmented regions, which were obtained by a therapeutic radiologist using a manual tracking method. In evaluating our segmentation method, we employed the Jaccard similarity coefficient (JSC) and the true segmentation coefficient (TSC) in volumes between the computer output and the manually segmented region. The mean and standard deviation of JSC and TSC were 74.2±9.8% and 84.1±7.1%, respectively. Our segmentation method provided a relatively accurate outline for GBM and would be useful for radiotherapy planning.抄録全体を表示PDF形式でダウンロード (901K)
臨床技術
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岩田 直樹, 紙谷 秀規, 山下 栄二郎, 平田 吉春2010 年 66 巻 4 号 p. 363-370
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル フリーMR brain surface imaging using a 3D T1 fast spoiled gradient recalled acquisition in the steady state (FSPGR) sequence with contrast medium is useful for surgical planning. However, this method has several problems such as use of the contrast medium. In this paper we evaluated the usefulness of MR 3D brain surface imaging using a non-contrast enhanced 3D T2 fast recovery fast spin echo (FRFSE) sequence as a new alternative method. This study includes 5 volunteers who underwent 3D volume rendering (VR) imaging using both a non-contrast enhanced 3D T1-SPGR sequence and a non-contrast enhanced 3D T2-FRFSE sequence, and 10 patients with brain tumors, who underwent preoperative 3D VR imaging using both a contrast enhanced 3D T1-SPGR sequence and a non-contrast enhanced 3D T2-FRFSE sequence. Four neurosurgeons assessed the visibility of sulci, gyri, and brain surface veins using a 4-point confidence scale on each VR image. 3D VR imaging using a 3D T2-FRFSE sequence was significantly superior to that using a 3D T1-SPGR sequence in the visualization of the sulci and gyri (p<0.05). In contrast, there was no significant difference between both sequences in the visualization of the brain surface veins. MR brain surface imaging using a non-contrast 3D T2-FRFSE sequence is at least equal or superior to 3D imaging using a contrast enhanced 3D T1-SPGR sequence in the preoperative planning.抄録全体を表示PDF形式でダウンロード (604K) -
若林 康治, 今井 嘉門, 諸澄 邦彦, 高橋 幸雄, 芝崎 匡樹2010 年 66 巻 4 号 p. 371-378
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル フリーA non-uniform attenuation correction is necessary for the myocardial perfusion image (MPI) SPECT that is one of the images of the trunk. Simultaneous non-uniform attenuation correction during the process of SPECT reconstruction was enabled by developing hybrid SPECT/CT. Image acquisition of 99mTc MPI with hybrid SPECT/CT was performed in a phantom study and clinical cases. We evaluated the effect of non-uniform attenuation correction by Filtered Back Projection (FBP) or Ordered Subsets-Expectation Maximization (OS-EM) using visual analysis and quantitative analysis with a 17-segment model. The phantom study and the clinical cases differed somewhat as follows. In the phantom study, the count increased significantly with non-uniform attenuation correction in visual analysis and quantitative analysis. In the clinical cases, non-uniform attenuation correction increased the quantitative count in the basal and middle layer of the heart, and visual uniformity of the whole heart improved. However, the visual and quantitative count in the apex decreased with non-uniform attenuation correction. As a result, diagnostic performance for coronary heart disease is expected to be improved by this new technique using hybrid SPECT/CT.抄録全体を表示PDF形式でダウンロード (608K)
教育講座-画像解析の基礎-
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寺部 充昭2010 年 66 巻 4 号 p. 379-384
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル 認証ありPDF形式でダウンロード (708K)
教育講座-研究成果を世界に向けて発信しよう! -
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西本 尚樹, 林 直樹, 内田 幸司2010 年 66 巻 4 号 p. 385-388
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル 認証ありPDF形式でダウンロード (385K)
基礎講座-第65回総会学術大会 教育講演から-
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宮崎 茂2010 年 66 巻 4 号 p. 389-398
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル 認証ありPDF形式でダウンロード (1275K)
基礎講座-パソコンソフト活用術-
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倉石 政彦, 杉野 雅人2010 年 66 巻 4 号 p. 399-403
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル 認証ありPDF形式でダウンロード (385K)
臨床技術講座
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前川 昌之2010 年 66 巻 4 号 p. 404-408
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル 認証ありPDF形式でダウンロード (445K)
JIRAトピックス
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前田 耕作2010 年 66 巻 4 号 p. 409-410
発行日: 2010/04/20
公開日: 2010/07/08
ジャーナル 認証ありPDF形式でダウンロード (322K)
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