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

田中 利恵

出版者

公益社団法人 日本放射線技術学会

雑誌

画像通信 (ISSN:1345319X)

巻号頁・発行日

vol.35, no.2, pp.94-99, 2012-10-01 (Released:2017-07-14)

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.

著者

中谷 香澄 福西 康修

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.5, pp.428-438, 2015 (Released:2015-05-20)

参考文献数

32

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Computed tomographic angiography (CTA) has been used recently for the evaluation of intracerebral aneurysms, but it is difficult to use this technique to visualize aneurysms near the base of the skull because of the presence of bone. So, subtracted CTA has been used to separate vessels from bony structures. However, we see some misregistration when using subtraction method because of the patient moving, the disaccord of the X-ray tube orbit between the mask image and the live image, the expanding focus, and the bed bending. So, attentioning the difference of bone CT number in any tube voltages, we examined to make the image containing less misregistration by changing the tube voltage of mask image. Making a sham blood vessel, we examined the bone misregistration, the blood vessel volume, and the smoothness when changing the tube voltages of mask images. Comparing with 120 kV, as the tube voltage of the mask image was 80 kV, the bone misregistration decreased significantly, however the blood vessel volume decreased. As for the tube voltage of 100 kV, the bone misregistration decreased significantly, and the blood vessel volume and the smoothness were not significantly different so we could get coordinative image of 120 kV. When the tube voltage of the mask image becomes lower than that of the live image and the effective energy becomes different, the effect of misregistration is less. This method deals with changing the tube voltage only. So, it may be easy to make volume rendering (VR) image and this method may be used in every facility.

著者

高羽 順子 升屋 亮三 池田 俊貴 中垣 五月 斉藤 温己

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.6, 1992

著者

高羽 順子 升屋 亮三 斉藤 温己

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.47, no.10, 1991

著者

菅原 努 中村 実 林 太郎 深津 久治 小野 伸雄 田口 武雄

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.14, no.1, 1958