著者

髙松 俊介 宮川 誠一郎 佐藤 久弥 鈴木 航 西澤 剛 中村 雅美 梅田 宏孝 崔 昌五 加藤 京一 中澤 靖夫 池田 純

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.70, no.6, pp.549-555, 2014 (Released:2014-06-20)

参考文献数

13

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The hamate bone, one of the carpal (wrist) bones, has a large uncinate process protruding from the palm side. In sports such as golf and tennis, the hamate bone can break if is subjected to a high external force, such as from the handle of a racquet or club. At our hospital we take X-ray images of the hamate bone from two directions: an axial image through the carpal tunnel and an image at the base of the hamate hook (conventional method). While the conventional method makes it easy to create images of the base of the hamate hook, the patient may suffer pain during image-taking because the hamate bone is pulled to cause radial flexion. We therefore investigated a method of imaging that would create three-dimensional computed tomography (3DCT) images of the base of the hamate hook in which the patient would only have to only rotate the wrist externally and elevate the fore-arm without any radial flexion. Our results suggest that it is possible to obtain images of the base of the hamate hook as clear as those acquired using the conventional method with the patient in a comfortable and painless position taking images at an external rotation angle of 50.3° and a forearm elevation angle of 20.3°.

著者

山田 澄人 山下 清司

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.50, no.8, 1994

著者

酒向 健二 松原 孝祐 松本 真

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.77, no.3, pp.284-292, 2021 (Released:2021-03-20)

参考文献数

22

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Purpose: A volume scan can cover a range of 160 mm with a single gantry rotation. It can be performed sequentially (a wide volume [WV] scan) to cover more than 160 mm, and volume Xact+ (Xact+) can be used when volume scan is done to extend the reconstruction area. The purpose of this study was to investigate the dose distribution and organ doses for a WV scan during chest CT. Method: We arranged radiophotoluminescence glass dosimeters (RPLDs) linearly on the surface and inside of the phantom to evaluate the dose distribution along the z-axis. We also placed RPLDs at the lens, thyroid, and breast positions to evaluate organ doses. We performed WV and helical scans and WV scan using Xact+. Result: The absorbed doses increased at the borders of the volume scans, and dose peaks were observed there. The organ doses for the WV scan outside the acquisition range were lower than those for the helical scan. The organ doses inside the acquisition range changed by the locations of borders. Conclusion: The WV scan increases the absorbed doses at the overlapping scanned regions, which can be reduced by using Xact+.

著者

尾崎 秀道 影山 勉 村木 威

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.41, no.5, 1985

著者

髙田 光雄 松原 孝祐 越田 吉郎 太郎田 融

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.71, no.4, pp.332-337, 2015 (Released:2015-04-20)

参考文献数

14

被引用文献数

2 5

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The purpose of our study was to investigate radiation dose for lower tube voltage CT using automatic exposure control (AEC). An acrylic body phantom was used, and volume CT dose indices (CTDIvol) for tube voltages of 80, 100, 120, and 135 kV were investigated with combination of AEC. Average absorbed dose in the abdomen for 100 and 120 kV were also measured using thermoluminescence dosimeters. In addition, we examined noise characteristics under the same absorbed doses. As a result, the exposure dose was not decreased even when the tube voltage was lowered, and the organ absorbed dose value became approximately 30% high. And the noise was increased under the radiographic condition to be an equal absorbed dose. Therefore, radiation dose increases when AEC is used for lower tube voltage CT under the same standard deviation (SD) setting with 120 kV, and the optimization of SD setting is crucial.

著者

田久保 早紀 川﨑 康平 長渡 努 松本 正信 景山 貴洋

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.76, no.2, pp.177-184, 2020 (Released:2020-02-20)

参考文献数

15

被引用文献数

1 7

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The aims of this study were to elucidate signal pattern of cerebral aneurysm clip in brain magnetic resonance angiography (MRA) using non-contrast enhanced ultra-short echo time (UTE) sequence and to explore effective utilization of this novel technique for patients, who underwent cerebral aneurysm clipping. The clip was embedded in homemade phantom and scanned using UTE sequence. We investigated characteristic features of the artifacts derived from the clip. Besides, we compared the volume of signal loss between conventional time-of-flight (TOF) and UTE-MRA in 50 patients with the cerebral aneurysm clip. In phantom study, the clip was delineated as signal void area fully surrounded by high signal on original images. On reconstructed short-axial views for the clip, four-leaf clover pattern of artifact was observed when clip was arranged orthogonal to the static magnetic field. On the other hand, this artifact disappeared when the clip was arranged in parallel with the static magnetic field. The volume of signal loss in clinical cases was significantly reduced in UTE-MRA (P < 0.05): 1.30, 0.52–2.77 cm3 for TOF; 0.84, 0.28–1.74 cm3 for UTE (median, range). The scan time for UTE-MRA was 2 minutes and 52 seconds. To understand the characteristic feature of the artifacts from the clip could contribute to define vascular structure in image interpretation. Adding UTE-MRA to routine protocol is useful approach for follow-up imaging after cerebral aneurysm clipping with clinically acceptable prolongation of the scan time.

著者

本間 龍夫 三浦 正和 藤井 博美

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.48, no.2, 1992

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日本においても海外交流が栄んになり、商品輸出入のみでなく、旅行者、研修生という外国人の入国がふえました。特に近隣の中国人、韓国人や南米2世のブラジル人等の人々が病院で治療をうけたり、検診をうける機会がふえましたが、各国語を話せる病院スタッフは大変少ないと思われます。その折X線室で撮影する先生方の替わりに外国語で話す音声装置があると便利である。又、耳の不自由な人や老人のペイシエントケア用品として表示器もあるが、CTガントリー内で寝ていても見えるように改良する必要があるという施設があった。

著者

保吉 和貴 佐藤 俊光 岡田 明男

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.74, no.8, pp.797-804, 2018 (Released:2018-08-20)

参考文献数

22

被引用文献数

1 1

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Purpose: This study aimed to evaluate the effect of adaptive iterative dose reduction 3D (AIDR 3D) on the computed tomography (CT) image quality by using single energy metal artifact reduction (SEMAR). Materials & Methods: A water phantom (22 cmφ) with the stem for total hip arthroplasty made of titanium was scanned. The volume CT dose index (CTDIvol) was set to 8.9 and 5.0 mGy. The reconstruction was performed using filtered back projection and AIDR 3D by soft kernel (FC13) and SEMAR. The averaged profile method was used for the quantitative evaluation of artifacts. We placed a rectangular region-of-interest on the artifact part, and obtained the x-direction averaged profile (Profile A). Profile B was obtained using a water phantom without metal. Profiles A and B were normalized as Profiles A′ and B′ using the mean value calculated from Profile B. Based on the standard deviation (SD) calculated from Profile B′, the background variation level was defined as ±2SD, and subtracted from Profile A′ (Profile A″). Finally, the area of Profile A″ was calculated and defined as Artifacttotal. Artifactover, and Artifactunder, respectively, the positive- and negative-side components of Artifacttotal. Results: Both Artifacttotal and Artifactunder increased according to the strength of AIDR 3D. The variations of Artifactover and Artifactunder, due to the AIDR 3D strength, were small and large, respectively. Further, in comparison with a high dose, the effect of artifact emphasis increased at low dose. Therefore, it should be noted that stronger AIDR 3D can emphasize the residual metal artifact.

著者

高橋 淳 小川 清 松田 恵雄 庭田 清隆

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.56, no.9, 2000

著者

加藤 清

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.10, 1955

著者

佐川 良 後藤 正美 秋山 晋

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.43, no.11, 1987

著者

石屋 博樹 千田 浩一 斎 政博 佐藤 弘之 有馬 宏寧 佐々木 正寿

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.49, no.8, 1993

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透視条件下において、X線アナライザの管電圧測定値と実測値はほぼ一致した。また、線量率測定に於いて、X線アナライザ2機種共に低い管電圧側で基準線量計の値より低い値を示し、管電圧が高くなる程、基準線量計の値に近づいた。今回の測定では、低い管電圧の時、線量率及び管電圧の測定が不能になったり、線量率の測定値が低くなったりするものもあったが、この原因としてはX線アナライザの測定レンジの下限を越えたためか、又は、検出限界ぎりぎりのところで測定したために起こったものと考えられる。以上より、X線アナライザは、透視条件という低いX線出力下においても、測定レンジの範囲内では充分QCに使用可能であると思われた。

著者

國友 博史 小山 修司 東出 了 市川 勝弘 服部 真澄 岡田 陽子 林 則夫 澤田 道人

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.70, no.7, pp.653-661, 2014 (Released:2014-07-23)

参考文献数

23

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In the detective quantum efficiency (DQE) evaluation of detectors for digital radiography (DR) systems, physical image quality indices such as modulation transfer function (MTF) and normalized noise power spectrum (NNPS) need to be accurately measured to obtain highly accurate DQE evaluations. However, there is a risk of errors in these measurements. In this study, we focused on error factors that should be considered in measurements using clinical DR systems. We compared the incident photon numbers indicated in IEC 62220-1 with those estimated using a Monte Carlo simulation based on X-ray energy spectra measured employing four DR systems. For NNPS, influences of X-ray intensity non-uniformity, tube voltage and aluminum purity were investigated. The effects of geometric magnifications on MTF accuracy were also examined using a tungsten edge plate at distances of 50, 100 and 150 mm from the detector surface at a source-image receptor distance of 2000 mm. The photon numbers in IEC 62220-1 coincided with our estimates of values, with error rates below 2.5%. Tube voltage errors of approximately ±5 kV caused NNPS errors of within 1.0%. The X-ray intensity non-uniformity caused NNPS errors of up to 2.0% at the anode side. Aluminum purity did not affect the measurement accuracy. The maximum MTF reductions caused by geometric magnifications were 3.67% for 1.0-mm X-ray focus and 1.83% for 0.6-mm X-ray focus.

著者

白石 順二

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.72, no.5, pp.I, 2016

著者

山口 紘子 松本 光弘 太田 誠一 植田 崇彦 筒井 保裕

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.68, no.5, pp.602-607, 2012-05-20 (Released:2012-05-30)

参考文献数

8

被引用文献数

1

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Introduction: We verified the setup error (SE) in two persons’ radiation therapist’s team, which consist of staff and new face. We performed the significance test for SE by the staff group and the new face group. Methods: One group consists of four staff therapists with at least 5 to 30 years of experience. The other group consists of new face radiation therapists that have 1 to 1.5 years of experience. Analyzed were 53 patients diagnosed with pelvic cancer (seven patients who underwent 3 dimensional conformal radiation therapy (3DCRT) and 46 patients who underwent intensity modulated radiation therapy (IMRT). Image verification was 1460 times. It was performed through setup verification by cone beam computed tomography (CBCT), and we measured SE of four directions (lateral, long, vertical, 3D). We performed the student’s t-test to get the difference of the average error between the staff group and the new face group. Results: The results of significance tests show that there is no difference between SE in the staff group and the new face group in radiotherapy.

著者

土橋 俊男 藤田 功 槇 利夫 北川 松雄 鈴木 健

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.54, no.4, pp.517-520, 1998-04-20 (Released:2017-06-29)

参考文献数

6

被引用文献数

4

著者

伊東 晶子

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.53, no.4, pp.485-489, 1997-04-20 (Released:2017-06-29)

参考文献数

15

被引用文献数

1

著者

土井 康寛 松山 倫延 池田 龍二 橋田 昌弘

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.72, no.7, pp.581-588, 2016 (Released:2016-07-20)

参考文献数

25

被引用文献数

1

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This study was conducted to measure the recognition time of the test pattern and to investigate the effects of the maximum luminance in a medical-grade liquid-crystal display (LCD) on the recognition time. Landolt rings as signals of the test pattern were used with four random orientations, one on each of the eight gray-scale steps. Ten observers input the orientation of the gap on the Landolt rings using cursor keys on the keyboard. The recognition times were automatically measured from the display of the test pattern on the medical-grade LCD to the input of the orientation of the gap in the Landolt rings. The maximum luminance in this study was set to one of four values (100, 170, 250, and 400 cd/m2), for which the corresponding recognition times were measured. As a result, the average recognition times for each observer with maximum luminances of 100, 170, 250, and 400 cd/m2 were found to be 3.96 to 7.12 s, 3.72 to 6.35 s, 3.53 to 5.97 s, and 3.37 to 5.98 s, respectively. The results indicate that the observer’s recognition time is directly proportional to the luminance of the medical-grade LCD. Therefore, it is evident that the maximum luminance of the medical-grade LCD affects the test pattern recognition time.

著者

金山 秀和 梶谷 尊郁 宮原 善徳 北垣 一 竹下 治男

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.76, no.8, pp.870-872, 2020

著者

古屋 研 秋山 真治 中村 公二 佐野 芳知

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.68, no.7, pp.835-840, 2012-07-20 (Released:2012-07-23)

参考文献数

20

被引用文献数

1

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We measured the time-dependent change of computed tomography (CT) values for a blood sample in a syringe during 20 days expecting that the (average, maximum) CT values may be used to estimate the elapsed time after hemorrhage. The average CT value (CTave) rapidly increased for the first 50 min. The maximum CT value (CTmax) increased step by step to take the largest value (82.4 HU) one day later, and subsequently the CTmax decreased slowly to become 72.0 HU 20 days later. We conclude that the rapid increase of the CTave at the beginning is due to the fibrin generation, the increase of the CTmax is a result of the formation of the fibrin net, and the subsequent decrease of CTmax is caused by fibrinolysis. Tentative experimental formula for the time-dependent CTmax change at each increasing stage and decreasing stage are given to estimate the elapsed time after hemorrhage.