著者

山口 隆義 高橋 大地

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.65, no.8, pp.1032-1040, 2009-08-20 (Released:2009-09-01)

参考文献数

12

被引用文献数

10 11

---

The test bolus tracking (TBT) method is a new injection method of contrast medium that we developed. The TBT method is an injection technique that continuously performs the test bolus injection and the main bolus injection, such that the best acquisition of scan timing and the improvement of examination efficiency can be expected. We compared the TBT method and the test injection method by coronary CT angiography. The results demonstrated that the contrast enhancement of the coronary arteries was high and the variation of the CT value was also small in the TBT method. When the scan timing expected by the TI method and the TBT method were compared, it was different of two seconds or more by the case with 43%. However, the variation of CT value was small for the TBT method in these cases. Therefore, the TBT method is a very useful method for CCTA.

著者

恒元 博 久津谷 譲

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.29, no.1, pp.2-10, 1973-05-31 (Released:2017-06-25)

著者

水谷 宏

出版者

公益社団法人 日本放射線技術学会

雑誌

放射線撮影分科会誌 (ISSN:1345322X)

巻号頁・発行日

vol.53, pp.22-24, 2009

著者

高橋 康幸 五十嵐 博 平野 邦弘 河原田 泰尋 五十嵐 均 村瀬 研也 望月 輝一

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.63, no.3, pp.335-340, 2007-03-20 (Released:2007-04-05)

参考文献数

9

---

An amendment concerning the enforcement of the law on the prevention of radiation hazards due to radioisotopes, etc., and the medical service law enforcement regulations were promulgated on June 1, 2005. This amendment concerned international basic safety standards and the sealing of radiation sources. Sealed radiation sources ≤3.7 MBq, which had been excluded from regulation, were newly included as an object of regulation. Investigation of the SPECT system instituted in hospitals indicated that almost all institutions adhere to the new amendment, and the calibration source, the checking source, etc., corresponding to this amendment were maintained appropriately. Any institutions planning to return sealed radioisotopes should refer to this report.

著者

藤淵 俊王

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.67, no.1, pp.63-68, 2009-11-25 (Released:2011-02-03)

参考文献数

14

著者

越田 吉郎 曽田 卓実 能登 公也 福田 篤志 松原 孝祐 中川 浩人 川端 千香子

出版者

公益社団法人 日本放射線技術学会

雑誌

日放技学誌 (ISSN:03694305)

巻号頁・発行日

vol.61, no.7, pp.989-996, 2005

参考文献数

20

被引用文献数

1 4

---

Medical personnel involved in abdominal angiography are exposed not only to direct radiation but also scattered radiation from inspection tables, patients, image intensifiers, and the beam-limiting system (collimator), among others. Japanese standard JISZ4831 prescribes protective coats of at least 0.25mm lead equivalent, which is the uniform thickness of lead equivalent. The most commonly used protective coats are 0.25mm Pb, 0.35mm Pb, or 0.5mm Pb in thickness. The weight of a typical protective coat is about 3kg. While some coats weigh up to 6kg, wearing such heavy coats becomes physically burdensome as inspection time increases. The trade-off between physical burden and protection was considered by analyzing the X-ray intensity distribution and attenuation rate of scattered radiation in each position assumed by the medical staff. In the case of inspections performed at an x-ray tube voltage of 80kV, it may be possible to reduce the weight of the lead rubber apron by about 33%. Namely, the lead thickness can be reduced uniformly by 0.20mm Pb at 70cm and 0.05mm Pb at 100cm, when the shielding capability of a 0.25mm thick Pb layer is accepted as the standard at 40cm above the gonad position. The same range of permeated X-ray dose for the gonad position may be reduced as well. In the case of 110kV, when the lead thicknesses are 0.30mm Pb at 40cm and 70cm, and 0.10mm Pb at 100cm, it is possible to reduce the weight of the lead rubber apron by about 28%.

著者

髙田 賢 市川 勝弘 坂野 信也 乙部 克彦

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.4, pp.315-325, 2018 (Released:2018-04-20)

参考文献数

31

被引用文献数

9 4

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The aim of this study was to inspect the usefulness of relative artifact index (AIr), which divided artifact index (AI) by standard deviation of the noise image for noise-independent evaluation of the streak artifact in computed tomography images. A water phantom without/with a cylindrical phantom filled with diluted contrast medium was scanned with different tube voltages (100/120/140 kV) and radiation doses (5/10/20 mGy), then images were reconstructed with different kernels (B10/30/50f). AI, location parameter in Gumbel method and AIr were measured in each condition and compared. The higher tube voltage or radiation dose or lower spatial resolution kernel, the lower quantitative values were presented by both AI and Gumbel method. AIr showed quantitative values independent of radiation dose and kernel, and substantial artifact amounts affected only by tube voltage. Our results showed AIr can evaluate quantitative artifact amount independent of image noise.

著者

福永 正明 大西 英雄 松友 紀和 山本 浩之

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.6, pp.489-495, 2016 (Released:2016-06-20)

参考文献数

12

被引用文献数

1

---

Purpose: The purpose of this study was to evaluate the effects of target diameter and display-field of view (D-FOV) in modulation transfer function (MTF) by circular edge strategy using the computed tomography (CT) image measurement program “CTmeasure”. Methods: We calculated the MTF (MTFedge) using the circular edge strategy applied to cylindrical phantom (200 mmφ) that inserted with cylinders have 10, 20, 30, and 40 mm diameters. The phantom images were reconstructed using filtered back projection method varied with D-FOV (240, 320, 400, and 500 mm). The study compared both MTFedge and MTFwire at MTF50% and MTF10% for target diameter and D-FOV, respectively. Results: The MTFedge by the different of target diameter indicated in rough compatibility. However, MTFedge of D-FOV diameters (320, 400, and 500 mm) decreased in the high frequency range. Conclusions: The circular edge strategy for MTF depended on the D-FOV, however, it was little dependent on target diameter using the CT image measurement program “CTmeasure”.

著者

土橋 俊男 藤田 功 岩崎 淳 森 克彦 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.58, no.3, pp.406-412, 2002-03-20 (Released:2017-06-30)

参考文献数

8

被引用文献数

1 1

---

During this project, we evaluated methods to prevent high-signal artifact (marching metal artifact) that are caused by magnetic substance. Marching metal artifact is caused by the resonance frequency created by magnetic substance. Phase encoding and frequency encoding are often switched to minimize the influence that marching metal artifact have on the image. However, this method will only change the position at which marching metal artifact occur. It does not have the ability to completely prevent marching metal artifact. Our research illustrated that marching metal artifact can be prevented by changing the strength of the slice selective gradient field at the 90° RF pulse and 180° RF pulse. In other words, marching metal artifact can be prevented by changing the frequency bandwidth for the 90° RF pulse and 180° RF pulse. The incorporation of the phase correct option in the device used for our research (SIGNA LX and SIGNA CV/i) results in different slice selective gradient field strengths at the 90° RF pulse and the 180° RF pulse. This indicates that the use of phase correction enables marching metal artifact to be prevented.

著者

本間 暁大 渡辺 東 大沼 孝司 三浦 康成 石川 辰美 木村 真 藤村 仁

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.59, no.9, pp.1104, 2003-09-20 (Released:2017-06-30)

著者

村山 大知 坂井 上之 米山 正己 能勢 毅一 畠山 英久 渡邉 一寿 越智 茂博

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.6, pp.572-580, 2021 (Released:2021-06-20)

参考文献数

17

---

Magnetic resonance angiography (MRA) using ultra-short TE (uTE) is known to be used for the evaluation of cerebral aneurysm after treatment such as clipping and coiling. However, conventional uTE sequences are not appropriate as an additional imaging sequence for 3D time-of-flight (TOF)-MRA because it is not possible to shorten scan time and acquire selective-volume imaging. To solve the problem, we focused on the combination of uTE sampling and 3D radial scan sequences. In this study, we examined the optimal imaging parameters of the proposed uTE-MRA. A simulated blood flow phantom with stents (Enterprise) and titanium clips (YASARGIL) was used for optimizing the TR, flip angle (FA), and radial percentage. The signal intensity in the simulated vessel was measured in each imaging condition, and the ratio of the presence or absence of a stent was evaluated as a relative in-stent signal (RIS). In addition, the diameter of the signal loss of the simulated artery was measured for each imaging condition, and signal loss length (SLL) of a clip was calculated from the average value. The RIS improved with increasing the FA and shortening the TR, but it did not change by changing the radial percentage. The SLL became smaller at the coil as the FA increased, but there was no significant difference between the intersection and the blade. There was also no significant difference between TR and radial percentage. The effective imaging conditions for uTE-MRA to improve the vascular description of the evaluation after treatment of cerebral aneurysms with metallic devices were those with large FA and short TR.

著者

山谷 裕哉

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.75, no.11, pp.1337-1346, 2019 (Released:2019-11-20)

参考文献数

22

被引用文献数

1

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We conducted a questionnaire survey (situation, patient factor, environmental factor, operator factor, degree of disability, countermeasure etc.) on cases that occurred up to the present to investigate the actual situation of the medical accidents that occur in the radiological examination department of medical institutions. There were 373 questionnaires collected. Among them, there were 197 cases of falls. In this study, we examined the age of patients who fell, the background of the accident, and factors. As for the accident, 11.7% of accidents with risk impact level 3b or higher occurred including the fatal accident. Of the accidents, 44.2% were foreseeable and 55.8% were unforeseeable. The most accident-prone age was elderly in their 60s to 80s. As the causative factor for the accident, the patient factor was the largest at 63.5%. We can prevent about 30% of the accident by improving the operator factor and the environmental factor which are parts other than patient factor. It is important for us to understand what kind of people tend to fall. Among foreseeable accidents, the causes of patient factors can be reduced.

著者

田中 琢真

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.79, no.10, pp.1189-1193, 2023-10-20 (Released:2023-10-20)

参考文献数

1

被引用文献数

3

著者

辰己 大作

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.79, no.5, pp.I, 2023-05-20 (Released:2023-05-20)

著者

表 英彦 荒井 博史 高橋 典子 勝浦 秀則 鈴木 幸太郎 久保 直樹

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.52, no.10, pp.1525, 1996-10-20 (Released:2017-06-29)

被引用文献数

1

著者

福永 晃太 圓﨑 将大 小味 昌憲 東 美菜子 平井 俊範 藤原 康博

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.79, no.7, pp.663-673, 2023 (Released:2023-07-20)

参考文献数

29

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【目的】Three-dimensional (3D) quantification using an interleaved Look-Locker acquisition sequence with T2 preparation pulse(QALAS)は,緩和時間を測定可能なシーケンスの一つである.3D-QALASは短時間に高い空間分解能で撮像可能な特徴があるが,3.0 Tにおける3D-QALASの緩和時間の測定精度や従来法とのバイアスは明らかになっていない.本研究の目的は,3.0 Tにおける3D-QALASの緩和時間を従来法と比較し,明らかにすることである.【方法】3D-QALASでファントムのT1値とT2値を測定し,それらの精度を評価した.次に,健常者の脳組織のT1値,T2値,プロトン密度を2D multi-dynamic multi-echo(MDME)と3D-QALASで測定し,それらの差を評価した.【結果】ファントムによる評価において,3D-QALASのT1値は,inversion recovery spin-echoのT1値より平均8.3%延長した.3D-QALASのT2値は,multi-echo spin-echoのT2値より平均18.4%短縮した.生体による評価では,3D-QALASの平均のT1値とT2値とPDは,2D-MDMEと比較して,それぞれ5.3%延長,9.6%短縮,7.0%増加した.【結語】3.0 Tの3D-QALASはT1値が1000 ms未満では測定精度が高いが,それ以上では過大評価される.また,3D-QALASのT2値は過小評価され,T2値が長いほどその傾向は大きくなる.

著者

有谷 航 中山 寛介

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.79, no.7, pp.708-716, 2023 (Released:2023-07-20)

参考文献数

16

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Magnetic resonance cholangiopancreatography(MRCP)は低侵襲に胆汁や膵液を直接画像化できる方法であり,Heavily T2強調3Dマルチスライス法では自由呼吸下で呼吸同期撮像を行うことで高画質な膵胆管の全体像が得られる.1回のデータ収集時間(echo train duration: ETD)を被検者の呼吸状態に合わせることで撮像時間が調整できるが,高速スピンエコー法におけるETDの変化は,画像コントラストや空間分解能に影響を与える.本研究では,ETDが画質に及ぼす影響について,ファントムを用いて評価した.いずれの条件でも模擬膵臓と模擬膵管は高い画像コントラストを示した.また,ETD延長に伴い空間分解能が劣化したが,視覚評価では有意差が認められなかった.より臨床的な条件では一部で視覚的に有意な差が認められ,phase partial Fourier(PPF)による影響が考えられた.PPFを使用せずに被検者の呼吸状態に応じてETDを変化させることで,画質を損なうことなく被写体の動きを抑えた最適な撮像時間での画像取得が可能になると考えられた.

著者

藤田 仁 森田 学 草加 勝康

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.64, no.6, pp.707-713, 2008-06-20 (Released:2008-07-19)

参考文献数

9

被引用文献数

1 1

---

In chest CT images, the dorsal lower lung field often shows an infiltration-like shadow in patients who cannot stop breathing or take a deep breath. The cause of this phenomenon might be due to the effects of gravity. Since we had observed decreased effects of gravity by conducting additional CT scanning for patients in an oblique position (55°) or a nearly lateral position, we conducted a clinical study to investigate this matter. Forty-three patients (23 patients in the normal group and 20 patients in the inflammatory disease group) who underwent additional CT scanning were included in this study. CT values for the region in which infiltration-like shadow was observed in both positions (dorsal position and oblique position) were measured. The ratio of fluctuation in the CT value of the dorsal lower lung field at a positional change from the dorsal to the oblique position was calculated as a coefficient of fluctuation C (%). As a result, the coefficient of fluctuation C (%) was 32.6±13.6 in the normal group and 6.7±6.8 in the inflammatory disease group. The effects of gravity were improved by additional CT scanning in an oblique position (55°) or a nearly lateral position, and this enabled differentiation of the effects of gravity vs. inflammatory diseases.

著者

豊島 功 中村 信明

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.33, no.1, pp.36-42, 2010-03-01 (Released:2017-07-14)

著者

堀江 朋彦 今田 奈津夫 榊原 夢太郎 厚見 秀樹 丹羽 徹 松前 光紀

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

pp.2023-1324, (Released:2023-02-14)

参考文献数

27

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【目的】本研究の目的は,呼吸性運動による脳脊髄液(cerebrospinal fluid: CSF)動態の描出を想定したdynamic improved motion sensitized driven equilibrium steady-state free precessionの最適な空間分解能と時間分解能を調べることである.【方法】健常ボランティア9名の正中矢状断面を対象に三つの撮像条件(A:空間分解能0.49×0.49×5 mm, 時間分解能1000 ms,B:0.49×0.49×5 mm, 430 ms,C:0.78×0.78×5 mm, 200 ms)による描出の違いを調査した.まず,第三,第四脳室のCSFおよび橋のsignal-to-noise ratio(SNR)を算出した.次に,呼吸性運動により10 cm/s以上で流れるCSFと10 cm/s以下で流れるCSFの信号強度比(signal intensity ratio: SIR)を算出した.更に吸気SIRと呼気SIRの差を求めた.更に,①中脳水道を中心とした第三,第四脳室に生じる流れの存在,②呼吸による流れの変化について,7名の技師による3段階の視覚評価により調べた.【結果】SNRは,いずれもAが最も高く次いでBそしてCの順に小さくなった.第三,第四脳室のCSFではAとBおよびAとCの間に有意差があったが,BとCには有意差はなかった.呼吸性運動によりCSFの信号強度は変化した.第三脳室のSIRは吸気で高く呼気に低くなり,逆に第四脳室のSIRは吸気に低く呼気で大きくなった.各SIRはいずれもAとCおよびBとCの間に有意差があった(p<0.05).吸気SIRと呼気SIRの差は,第三,第四脳室ともにBが最も高く次にAそしてCが最も低く,AとCおよびBとCの間に有意差があった(p<0.05).中脳水道を中心とした第三,第四脳室に生じる流れの存在に有意差はなかった(p=0.264).一方,呼吸による流れの変化には撮像条件による有意差がありBが他より高値となった(p<0.001).【結語】最適な空間分解能は0.49×0.49×5 mm, 時間分解能は430 msであった.また本法では,位相分散を利用するため空間分解能と時間分解能の関連に注意した条件設定が重要なことが示唆された.