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Article type: Cover
2005 Volume 61 Issue 3 Pages
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Article type: Index
2005 Volume 61 Issue 3 Pages
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Article type: Index
2005 Volume 61 Issue 3 Pages
Toc12-
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[in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
I-
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
A2-
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
A4-A5
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
A6-A8
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Toshihiro Ogura, Kazuaki Takatsu, Ryouichi Negishi
Article type: Article
2005 Volume 61 Issue 3 Pages
305-312
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Kazunori Yoshida
Article type: Article
2005 Volume 61 Issue 3 Pages
313-318
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TOHRU HIRANO
Article type: Article
2005 Volume 61 Issue 3 Pages
319-334
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TAKAO ICHIDA
Article type: Article
2005 Volume 61 Issue 3 Pages
335-343
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TOKUO UMEDA, [in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
344-348
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TAKASHI TABUCHI
Article type: Article
2005 Volume 61 Issue 3 Pages
349-358
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...
Article type: Article
2005 Volume 61 Issue 3 Pages
359-371
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TORU FUJITA, [in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
372-374
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TAKAO OBARA
Article type: Article
2005 Volume 61 Issue 3 Pages
375-380
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KOZO KUMAGAI, [in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
381-
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SHUICHI DOHI
Article type: Article
2005 Volume 61 Issue 3 Pages
382-384
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HIROYUKI NAGASHIMA, SHINICHI SUNAGA, TOYOHISA MITOME, EIICHI KOYA, HIR ...
Article type: Article
2005 Volume 61 Issue 3 Pages
385-391
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Because the exposure dose in X-ray computed tomography examinations is sometimes difficult to determine, it is important to be able to estimate the dose for these examinations. The effective energy of the X-ray CT scanner is required to estimate exposure dose. Although the half-value-layer(HVL) method has been used to calculate effective energy, it is not an easy method. This paper proposes a technique by which effective energy can be easily calculated. Certain details were found to cause change in effective energy, and the ratio (inner-metal center-air ratio : IMCAR) between air dose and dose in fixing the metallic pipe in the isocenter of an X-ray CT scanner was necessary. The IMCAR from a different X-ray CT scanner was required, and, when effective energy was calculated, it showed an error of less than 0.7% for the half-value-layer method. The effect of this error on dose estimation was slight (0.4%). This technique is useful, because effective energy can easily be calculated with a high degree of accuracy.
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KIYOSHI AOKI, MASAKI KOYAMA
Article type: Article
2005 Volume 61 Issue 3 Pages
392-400
Published: March 20, 2005
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The absorbed dose conversion factor for X-rays at the water phantom surface has been obtained from the measured spectra. These measurements have been made at tube voltages of 60 kV to 120 kV and field sizes ranging from 5×5 cm^2 to 30×30 cm^2 with and without additional 2 mm aluminium filtration. A small silicon diode detector with little angular dependence was used for this measurement. The absorbed dose conversion factor obtained was 0.03-0.43% smaller than that obtained from the primary X-ray spectrum. The difference was large for high-voltage and heavily filtered X-rays. As field size increases, the conversion factor decreases, but the decrease is slight when field size exceeds 20×20 cm^2. The absorbed dose conversion factor obtained from the primary or surface X-ray spectrum is 0.4-1.8% larger than that obtained from the effective energy of primary X-rays. The difference is large in high-voltage X-rays and decreases slightly with increases in field size.
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MASATO MAENO, JUN TACHIBANA, KAORI YAMAMOTO, KENYA UCHIDA, TAKESHI KOI ...
Article type: Article
2005 Volume 61 Issue 3 Pages
401-408
Published: March 20, 2005
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The BOLD signal responses that occur after a few seconds at the beginning and the end of stimulus are due to hemodynamic delay. A temporary increase of deoxyhemoglobin just after the beginning of stimulus causes an initial dip in the hemodynamic signal (response). After the initial dip, an increase of BOLD signal causes an overshoot. After the overshoot, a decrease of the BOLD signal due to the end of stimulus causes an undershoot. Many reports have examined the period of stimulus, but only a few have described the period after stimulus. This paper reports on a peak between the overshoot and undershoot. After the end of stimulus, the signal does not simply decrease, but shows a peak after some delay. An activated map showed the same tendency as the hemodynamics signal. This peak was termed hemodynamic over-saturation (HOS). Time control in chronological order is important to obtain a hemodynamic change in chronological order and a large, significant difference between the task and rest signal. The entire hemodynamic signal was evaluated by controlling the timing of the scan using an external trigger and by indicating the beginning of the task (rest) period using sound. The timing of the external trigger and sound are built into the sequence design as a program. From the results of the hemodynamic signal, the causal relationship between this signal and the fluctuation in oxyhemoglobin and deoxyhemoglobin can be considered.
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NARUOMI AKINO, KATSUMI TSUJIOKA, HIROFUMI ANNO, YOSHIHIRO IDA, HIRONOR ...
Article type: Article
2005 Volume 61 Issue 3 Pages
409-418
Published: March 20, 2005
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One of the newest CT application technologies is cardiac synchronized image reconstruction. In this technology, evaluation of time-resolution is very important. We developed a method of measuring time-resolution in cardiac synchronized reconstruction, and evaluated various scanning protocols. In our experiment, ECG-gated scanning was done by multi-slice CT (Aquilion 16 Super Heart Edition, Toshiba Medical Systems Co., Ltd., Japan). The nominal slice thickness was 0.5 mm, and rotation time was 0.5 sec. Input heart rate was set at 40, 45, 50, 55, 60, 70, 75, 80, and 90 bpm, and helical pitch at 3.2, 4.0, and 4.8 (beampitch : 0.200, 0.250 and 0.300). We measured FWTM of the obtained sensitivity distribution and compared at each scanning protocol. Time resolution improved as helical pitch decreased and heart rate increased. However, phase-time resolution deteriorated as heart rate increased. The results of our experiment indicated that a segment center was determined by X-ray tube rotation time and heart rate, and the number of segments was determined by heart rate, helical pitch, and reconstruction position. Time resolution changed with X-ray tube rotation time, heart rate, helical pitch, and reconstruction position. In this report, we provide a reference for an optimal scanning protocol in cardiac synchronized image reconstruction.
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KUMI ISHIHARA, ETSUKO ISHIDA, HIDEYUKI IWANAGA, MASAHIRO HASHIDA, TAIZ ...
Article type: Article
2005 Volume 61 Issue 3 Pages
419-425
Published: March 20, 2005
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The multi-objective frequency processing installed in the FCR5000R (Fuji Film Medical) is superior to the conventional processing used in the FCR9000 (Fuji Film Medical) in evaluating frequency processing. A suitable combination of parameters for multi-frequency-processing in computed radiography (CR) mammography was evaluated. The paired-comparison method using phantom images was performed for the visual evaluation. Results showed that the evaluation score of mass and fiber lesions depended on the multi-frequency balance type (MRB) parameter, and the low-frequency-cycle emphasizing parameter had the highest score. In contrast, the score of microcalcifications depended on the degree of multi-frequency enhancement (MRE). The most suitable parameters for the multi-frequency processing of every size and type of breast lesion were not obtained. However, MRB=A, MRT=p, and MRE=1.0 can be recommend for CR mammography.
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Xuejun Zhang
Article type: Article
2005 Volume 61 Issue 3 Pages
426-
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
427-428
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
429-
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
430-435
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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2005 Volume 61 Issue 3 Pages
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2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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Article type: Appendix
2005 Volume 61 Issue 3 Pages
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[in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
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[in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
2-5
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[in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
6-9
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[in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
10-13
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[in Japanese]
Article type: Article
2005 Volume 61 Issue 3 Pages
14-17
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Article type: Cover
2005 Volume 61 Issue 3 Pages
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