担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.18926/AMO/64361

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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記述言語：日本語   掲載種別：研究論文（学術雑誌）  

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担当区分：最終著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.14316/pmp.2021.32.2.50

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

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担当区分：責任著者   記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ELSEVIER IRELAND LTD  

Purpose: Our aim is high spatial resolution imaging of maximum intensity projection (MIP) images in renal magnetic resonance angiography (MRA) by constructing a protocol for acquiring three-dimensional volume data with isotropic voxels.
Materials and methods: We eliminated water-selective excitation (WATS) and utilized effective contrast behavior between fat and water before reaching a steady state-that is, during the transient phase-to cover fat suppression by WATS. In a phantom study, the optimal flip angle was investigated under the "low-high Y" profile order using distilled water and baby oil to construct a protocol with isotropic voxels. Signal intensity, contrast, noise and signal-to-noise ratio were investigated to compare image qualities between the conventional and the constructed isotropic protocols. In a clinical study, three radiologists and two radiological technologists visually evaluated clinical images of 20 volunteers for spatial resolution, contrast and overall reader confidence in two protocols.
Results: We constructed an isotropic protocol with voxel dimensions of 0.78 mm x 0.78 mm x 0.78 mm at a flip angle of 90 degrees. We maintained the scan time but enlarged the x-y pixel dimensions from 0.59 mm x 0.59 mm to 0.78 mm x 0.78 mm and shortened image height from 48 mm to 42.9 mm. Data from the phantom study were worse in the isotropic protocol than in the conventional protocol. However, overall reader confidence in the clinical images was significantly better in the isotropic protocol than in the conventional protocol (p < .001).
Conclusion: Our study indicated the value of addressing high spatial resolution imaging of MIP images for renal MRA by constructing an isotropic protocol. (C) 2011 Elsevier Ireland Ltd. All rights reserved.

DOI： 10.1016/j.ejrad.2011.02.031

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担当区分：責任著者  

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記述言語：日本語   出版者・発行元：Japanese Society of Radiological Technology  

Measurement of a percent glandular tissue composition (%GTC) is important in terms of the estimation of individual patient exposure dose and the prediction of malignancy, and thus a number of reports for estimating %GTC by use of a mammogram have been published. In this study, we propose a method for estimating individual %GTC by use of computed radiography (CR) mammograms. By employing breast-equivalent phantoms that are able to create breast phantom images with various combinations of fat and glandular tissue, as well as the thickness of whole breast, we determined a reference table for converting an each pixel value on CR mammography to the glandular tissue ratio. Therefore, the %GTC for individual breast was estimated by averaging glandular tissue ratio for a whole region. The clinical image data set that consisted of 49 CR mammograms were used for estimating %GTC. A paired comparison method for determining subjective ranking of the degree of breast density was employed in order to demonstrate the validity of our method. The results indicate that the average estimated %GTC was 35.0% (ranged from 12.0% to 67.0%) and they had a increased correlation with the ranking of those obtained by observer test. Therefore, it was suggested that our proposed method would be utilized for estimating the %GTC in objective manner.

DOI： 10.6009/jjrt.67.1540

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その他リンク： https://jlc.jst.go.jp/DN/JALC/00384818611?from=CiNii

記述言語：日本語   出版者・発行元：岡山赤十字病院医学雑誌編集委員会  

MRIにおいて軟部組織と空気境界面は、磁化率変化によるアーチファクトが起こりやすい。通常、MRIでは脂肪抑制法が頻繁に用いられるが、磁化率の変化は脂肪抑制のムラを引き起こす。その脂肪抑制ムラは、解剖学的な形状のために、頸部で頻繁に生じる。本研究では、磁化率変化を軽減する補助具(Sat-Pad)の作製を試みた。(著者抄録)

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記述言語：日本語   出版者・発行元：公益社団法人 日本放射線技術学会  

Radiochromic film (RC-film) is of great interest as a film-type dosimeter for radiation oncology applications. We present a two-dimensional image-based evaluation of the measurement accuracy of a commercial RC-film product (Gafchromic MD-55-2 film, ISP TECHNOLOGIES, Inc.) by using a commercial Laser Densitometer (Model 1710, Computerized Medical Systems, Inc.) as an optical density imaging system. The coefficient of variation of the density (pixel-value) in one sample was approximately 3% to 11 % at 3 Gy or less, and 3% or less at 4 to 60 Gy. Although the coefficient of variation between three samples at the same dose was about 14% at 1 Gy, it decreased as the dose increased, reaching several percent. In 1 to 6 Gy samples, geometric imaging artifacts [interference (moire) patterns] were observed, and it was found that scan-sampling pitch influenced the accuracy of measurement of the density of the sample. To improve the accuracy of density measurement, sufficient knowledge about characteristic features of the density measuring system is essential.

DOI： 10.6009/jjrt.KJ00003326577

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担当区分：筆頭著者   記述言語：英語  

DOI： 10.11409/mit.21.369

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記述言語：日本語   出版者・発行元：公益社団法人 日本放射線技術学会  

Rates of Flow of barium meal into the bowel and ease of swallowing a barium meal and foaming agent were investigated according to the procedure of administration, in order to study the timing of adding the foaming agent. In group medical examinations, the flow rates of barium meals of 100 examinees given a barium meal followed by a foaming agent were compared with those of the same examinees given the foaming agent first. Parasympatholytic agents were not administered in this study. When the foaming agent was given before the barium meal, the flow rate of the barium meal into the bowels was 44.0%. In contrast, when the foaming agent was given after the barium meal, the rate was 78.0%. A total of 67.3% of 101 Volunteers given the foaming agent and the barium meal twice in the reverse order answered that it was easier to swallow the barium meal first. When a parasympatholytic agent is not given, it is better to give the foaming agent first, even though it is more difficult to swallow the barium meal after the foaming agent, because it is most important in examination of the stomach that the barium meal does not flow out into the bowel.

DOI： 10.6009/jjrt.KJ00001357562

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記述言語：日本語   出版者・発行元：岡山大学医学部保健学科  

幼小児を含めた若年者の股関節X線撮影検査においては鉛板などで生殖腺を防護して行うのが通常である。男性の場合は生殖腺は体外に露出しているので，それを鉛板で包むようにすればある程度目的は達成される。しかし，女性の場合，生殖腺は骨盤腔内に存在するため，卵巣及び子宮を防護でき診断目的領域にかからないように鉛板を成形し，腹壁上に置いて撮影する。X斬写真上ではグリッドで散乱線を除去しているため，鉛板の陰影がくっきりと撮影され，生殖腺は完全に防護されているように見える。しかし，体内では散乱線によるかなりの被曝があるものと考えられる。そこで今回，鉛板下の散乱線量を鉛板幅及び電圧を変化させ，ファントム内各深さの散乱線量を測定した。その結果，鉛板下の散乱線量が相当量認められ，その量は深さ3～4cmでピークを形成した。鉛板幅による変化は幅が狭いほど線量は大きくなり，電圧による変化は60kVと80kVを比べると80kVの方が多くなった。これを鉛板なしの場合と比較すると，ファントム内意さが増すにしたがい増大した。したがって，臨床において鉛板がずれて再撮影をすることのないよう細心の注意が必要であると考えられた。Usually in a hip-joint radiographic examination for the youth including children, the gonads should be well protected with an appropriate lead shield etc. Since themale gonads are in the outside of the body, if covered with a lead shield, the shield can protect them. However, in the case of the female, since the gonads of exist in a pelvic cavity, the lead shield is cut to a specific pattern so that it can protect the ovaries and the womb,and it is set on the abdomen during the radiographic exposure. Since the scattered radiation on an X-ray film can be removed with the grid, the image of a lead shield is obtained clearly, and the gonads seem to be protected completely. The shield can not protect the gonads of the female from the scattered radiation, though it protects them almost completely from the primary X-rays beam. Therefore, the gonads have radioactive contamination from scattered radiation. Then, in order to estimate the amount of scattered radiation under the lead shield, the dose under the shield was measured by using a phantom in this research, changing lead shield width, the tube-voltage, and the monitoring depth of a phantom. As a results, the dose under the lead shield was observed considerably and showed the peak at the depth of 3 or 4cm. Therefore, it was thought that a careful caution was required for obviating lead shield in clinical.

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その他リンク： http://search.jamas.or.jp/link/ui/2001185919

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担当区分：責任著者   記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

低エネルギー領域のマンモグラフィに使用される片面増感紙/片面乳剤フィルムシステムの特性曲線作成に対しては空気減弱が問題となる.そこで, 異なるX線エネルギー励起におけるマンモグラフィ用増感紙の蛍光スペクトルを測定し, 増感紙の蛍光発生に対するエネルギーによる影響を検討した.またマンモグラフィ専用装置の低エネルギーX線を用いて, 距離によって連続的に変化するエネルギー分布に対応した空気減弱のより正しい補正を試みた.さらに一般撮影領域のX線エネルギーを用いて作成した特性曲線とマンモグラフィ専用装置の低エネルギーX線を用いて空気減弱分を補正して得られた特性曲線を比較した.その結果, 空気減弱分が無視できるX線エネルギーを選択すれば, 特性曲線を作成できる可能性が得られた.

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担当区分：筆頭著者   記述言語：英語   出版者・発行元：岡山大学医学部保健学科  

The average glandular dose to glandular tissue m mammography is generally assumed to be a function of beam quality (HVL), x-ray tube target material, tube voltage, breast thickness, breast composition and, to a lesser extent, x-ray tube voltage waveform. The average glandular dose is generally determined from published tables with knowledge of the above function. Tables for a high frequency x-ray generator are not yet published. In our study, the lookup tables for the average glandular dose were made at 28 kV (high frequency x-ray generator), employing a breast simulating tissue (0-100% adipose tissue, 0-100% glandular tissue) phantom for an Mo target - Mo filter source assembly. We tried to estimate breast composition from x-ray mammograms by digital image processing techniques, also using the simulating tissue phantom. Then the system that automatically calculates the average glandular dose from digitized clinical x-ray mammograms was built. It is considered that this system can contribute to objective evaluation of the averageglandular dose.乳房X線撮影法において乳腺組織に対する平均放射線吸収線量，すなわち平均乳腺線量は放射線のリスクの最も有用な測定法であり，現在，乳房に対する線量の評価に用いられている指標である。一般に，平均乳腺線量は線質（HVL），X線管球ターゲット材料，管電圧，圧迫乳房厚さ，乳房構成および（ある程度）X線管電圧波形の関数であるとされている。平均乳腺線量は，上記の関数についての情報を備えた表が公表されており，一般にその表を使って決定されている。近年，インバータ式といわれる高周波X線発生装置が普及してきた。しかし，その装置用の表は，まだ公表されていない。我々の研究では，乳房組織をシュミレートするファントム（0～100％乳腺組織，0～100％脂肪組織）を使用して，28kVでMoターゲット―Moフィルタソースアセンブリーを備えた高周波X線発生装置のために，平均乳腺線量用のルックアップテーブルを作成した。同様に，乳房組織をシュミレートするファントムを使用して，乳房X線写真から，ディジタル・イメージプロセシング技術によって，乳房構成の評価を試みた。そして，ディジタイズされた臨床乳房X線写真から，平均乳腺線量を自動的に計算するシステムを構築した。サンプル数が少ないため断定はできないが，日本女性は，基準構成（50％の脂肪および50％の乳腺組織）と比較すると，脂肪が少ない傾向を分析結果は示唆していた。また，平均乳腺吸収線量の限度は，明確に規定されていないが，American College of Radiology（ACR）は4 mGyなどを推奨している。また日本では，3 mGyが推奨されているが，我々の撮影システムはこれらを十分満足していた。このように本システムは，平均乳腺線量の客観的な評価に寄与するとともに，DR（digital radiography）などに応用すると，すなわちルックアップテーブルをDRのコンピュータに保存しておけば，撮影後すぐに乳房構成および平均乳腺線量を算出できる可能性をもつ。

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記述言語：英語   出版者・発行元：公益社団法人 日本放射線技術学会  

Two kinds of gastric images of 85 examinees were compared in order to study the procedure of giving barium meal and forming agents The more recent images were obtained with examinees given a barium meal followed by a forming agent, whereas the other images were of the same examinees obtained the previous year, with the foaming agent given before the barium meal. Results showed that when the barium meal was given first, the mucous membrane of the stomach was imaged better. In contrast, when the forming agent was given first, sodium tartrate, derived from the foaming agent, was considered to cover the mucous membrane and physically to prevent the barium meal from clinging to the membrane.

DOI： 10.6009/jjrt.KJ00001356895

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担当区分：責任著者   記述言語：日本語   出版者・発行元：公益社団法人 日本放射線技術学会  

We applied an extended-cycle process, in which the processing time is longer than the manufacturer's recommendation, to a low-speed, high-resolution system in mammography and investigated to what extent sharpness, contrast, and speed would be maintained or increased and whether this process could be applied clinically. In this study, a single-screen/single-emulsion film, Konica M-100/CM-H, was used in the lowspeed, high-resolution system, and M-200/CM-H was employed for comparison. Developing temperatures of 30, 32, and 34 degrees centigrade and a processing time of 210 seconds were selected as conditions of the extended-cycle process. M-100/CM-H with the extended-cycle process(M-100/E system)and M-200/CM-H with the standard-cycle process were compared at 34 and 90 seconds(M-200 system)in terms of contrast, speed, modulation transfer function(MTF), and Wiener spectrum(WS). In addition, the visibility of mammograms obtained using an RMI 165 phantom was evaluated by the method of paired comparisons. In the comparison of the M-200 system with the M-100/E system at 34 and 210 seconds, the speed was almost equal and the average gradient and MTF value at 2.5 cycles/mm increased about 20% and 8%, respectively. Ws was higher due to the increase in quantum mottle with increases in the average gradient and MTF. In the scale of the method of paired comparisons, M-100/E systems showed better results. Moreover, entrance skin exposure in air of the M-100/E system at 34 and 210 seconds was almost equal to that of the M-200 system. These results suggested that it was possible to improve visibility by the extended-cycle process in a low-speed, high-resolution system.

DOI： 10.6009/jjrt.KJ00001357361

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担当区分：責任著者   記述言語：日本語   出版者・発行元：公益社団法人 日本放射線技術学会  

With single-emulsion films like those used in screen/film mammography, if the developing temperature is higher and/or the processing time is longer than recommended (i.e., extended-cycle process), film speed and/or film contrast are effectively increased. However, it can also be expected that radiographic noise will be increased by the extended-cycle process. Therefore, film graininess and radiographic mottle were investigated with standard-and extended-cycle processes in four single-screen/single-emulsion film systems for mammography, the Konica M-150/New CM, Fuji UM MAMMO Fine/UM-MA HC, Kodak Min-R2000/Min-R2000, and Kodak Min-R Medium/Min-R M. Investigation was carried out by measurement of the Wiener spectrum (WS). Results showed that the WS of film graininess increased in all films. The increase was greatest in Min-R M, and the rate of increase at 2.0 cycles/mm was 1.67 or more. The film showing the smallest increase was UM-MA HC, for which the rate of increase was 1.03-1.21. There were cases in which the spatial frequency at a 50 percent contribution rate of film graininess to radiographic mottle changed to a low spatial frequency. When only the increase in WS of radiographic mottle was examined, the increase was greatest in Min-R Medium/Min-R M, and the rate of increase at 2.0 cycles/mm was 1.65 or more. Min-R2000/Min-R2000 showed the least increase, and the rate of increase was 1.12-1.24. Increases in WS values were larger at 0.1-0.5 cycle/mm than at 2.0 cycles/mm when investigating the influence of trend using film graininess, and roller marks and so on could not be specified as a cause.

DOI： 10.6009/jjrt.KJ00001357002

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記述言語：日本語   出版者・発行元：岡山大学医学部保健学科  

マンモグラフィ専用装置を使用して，距離法で低エネルギー領域のX線におけるマンモグラフィ用増感紙／フィルムシステムの特性曲線を得るためには，空気滅弱の影響を考慮する必要がある。その影響について，実効エネルギーから空気減弱分を補正，照射線量測定による補正，Bednarek法を応用した新距離法の3種類の方法を使って検討した。さらに，一般撮影装置でも，マンモ用システムに対して距離法で特性曲線を作成し，エネルギーの変化による影響についても検討した。その結果，3方法の特性曲線およびグラディエント曲線は，新距離法が高濃度域でわずかにずれるもののほぼ一致した。新距離法に対する平均階調度，最大階調度の最大誤差は，2.7％，0.2％であり，一般撮影用装置の距離法と3方法との間では，一般撮影用装置の距離法に対して最大誤差は2.7％，1.5％であった。以上のことから，エネルギーの変化による特性曲線への影響はほとんどなく，低エネルギー領域での特性曲線は空気特配の補正を行うことのみで得られると考えられる。It is necessary to take air attenuation into account when we use inverse square sensitometry to obtain characteristic curve for the mammographic screen-film system at low x-ray energies as used with the dedicated unit. Three kinds of the inverse square sensitometry approach of correcting by air attenuation obtained from effective energy, of correcting by exposure dosimetry and of using modified the technique of Bednarek were employed to investigated the influence of x-ray energy in the characteristic curves for the mammographic screen-film system. In addition, the inverse square sensitometry with the general radiographic unit was employed and the influence of x-ray high energy in the characteristiccurves was also investigated for the same screeri-film system. Though characteristic curves and gradient curves of the new inverse square sensitometry were a little lower than the others in high-density region, the curves with three kinds of methods almost coincided. Maximum relative errors of average gradient and maximum gradient for modified the technique of Bednarek were found to be 2.7% and 0.2% among the others respectively. Moreover, maximum relative errors of gradient and maximum gradient for the inverse square sensitometry with the general radiographic unit were 2.7% and 1.5% among three kinds of methods with the dedicated unit respectively. It was considered that the characteristic curves for the mammographic screen-film system were little influenced by x-ray energy and could be obtained only by correcting air attenuation from above results.

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その他リンク： http://search.jamas.or.jp/link/ui/2000278800

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記述言語：英語   出版者・発行元：岡山大学医療技術短期大学部  

Extended-cycle process is the term used for a processor in which the processing time has been prolonged usually to approximate 210 seconds. It has been known that the extended-cycle process of some single-emulsion films as used for mammography may enhance film contrast and increasefilm speed. So the speed was increased in lower speed and higher resolution system than conventional systems by means of using the extended-cycle process in this paper. We investigated how much the resolution of the system was kept. A single screen-single emulsion combination, KonicaM-100/CM-H was employed as a low speed and high resolution system. This film after exposure was processed in the different combinations of developing temperatures, 30, 32 and 34℃, and processing time of 210 seconds. On the other hand, Konica M-200/CM-H was employed as a high speed system. This film was processed in the standard-cycle processing (34℃, 90 seconds). Those systems were compared on contrast, speed, screen-film blur and noise by a characteristic curve, MTF (modulation transfer function) and WS (wiener spectrum). Furthermore, the RMI 165 phantom was used to evaluate visibility of mammographic details of these systems. As a result, in the extended-cycle process at the developing temperatures of 32 or 34°C andprocessing time of 210 seconds for M-100/CM-H, it was possible to increase the speed as much as the higher speed system, M-200/CM-H. Then the contrast, the MTF and the visibility were also improved as compared to the higher speed system. Furthermore patient dose could be reduced atthe developing temperature of 34℃ and processing time of 210 seconds in M-100/CM-H.通常,extended-cycle processは処理時間が約210秒に延ばされた現像機のために使われる用語である｡乳房撮影に使われるような片面乳剤フィルムにおけるextended-cycle processは,フィルムコントラストを増し,感度をあげることが良く知られている｡そこで,本論文ではextended-cycle processにより低感度,高解像度システムの感度を上げ,どの程度解像度が維持されるかを調べた｡片面増感紙／片面フィルムの組合わせであるKonica M-100/CM-Hを低感度,高解像度システムとして用いた｡露光後のフィルムは現像温度30,32, 34度,処理時間210秒の異なる組合わせで現像処理した。一方,高感度システムとしてKonica M-200/CM-Hを用い,このフィルムは標準現像(34℃,90秒)された｡感度,増感紙／フイルムのぼけ,雑音に関して,特性曲線,MTF(modulation transfer function), WS(wiener spectrum)によってこれらのシステムを比較した｡さらにこれらのシステムにおける乳房写真の細部視覚評価のためにRM165ファントムを使用した｡その結果,M-100/CM-Hに対するextended-cycle process現像温度32, 34℃,処理時間210秒のextended-cycle processにおいて,高感度システムM-200/CM-Hと同等の感度を上げることが可能であった｡そのとき,コントラスト,MTF,視覚的検出能も高感度システムより向上した｡さらに,現像温度34℃,処理時間210秒では,被曝線量の低減が可能であった｡

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その他リンク： http://eprints.lib.okayama-u.ac.jp/15252

担当区分：筆頭著者   記述言語：日本語   出版者・発行元：公益社団法人 日本放射線技術学会  

Film graininess can be measured by providing air spaces between the screen and film in the screen-film system. In this study, the necessary air spaces were investigated to measure mammographic film graininess by using a mammography unit at the low tube voltage of 28 kV. Wiener spectra were measured with the screen held 1, 3, 6, 9,15, 21, and 30 mm from the film at densities of 0.8 and 1.3. Konica New CM film with a Konica M-150 screen was employed in this investigation. Results showed that Wiener spectral values were almost constant at densities of 0.8 and 1.3 when the air spaces were 9 mm or more. That is, it was considered that film graininess was evaluated independently by blurring quantum mottle, and 15 mm air spaces were used to provide a safety margin. Furthermore, film graininess of three mammographic films, Fuji UM-MA HC (with a Fuji UM MAMMO Fine screen), Kodak Min-R 2000 (with a Kodak Min-R 2000 screen), and Kodak Min-R M(with a Kodak Min-R Medium screen)were measured with 15 mm air spaces. Min-R 2000 film had the lowest Wiener spectral values for film graininess at low spatial frequencies.

DOI： 10.6009/jjrt.KJ00000921418

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記述言語：日本語   出版者・発行元：岡山大学環境管理センター  

In 1995, we have published a paper about the basic data on the relation between X-ray exposure equipment and patient dose in Vol. 17 of the Journal "Environment Research and Control". In this time, we questioned hospitals in Okayama Prefecture about exposure equipments of abdomen. And we compared each hospital's exposure equipments with the basic data, calculated each patient dose, then we studied that differences. Various imaging system, for example; screen/film or imaging plate has been used at each hospitals, so that exposure are various and patient doses are very different. The exposure equipment decide that the X-ray photograph is good or bad, so we cannot treat it easily. But we think that we have to try to take X-ray photographs which are suit the purpose of diagnosis which as a small patient dose as possible.

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記述言語：英語   出版者・発行元：岡山大学医療技術短期大学部  

The influence for developing temperature and processing time within film processing conditions was investigated using four mammographic films, Konica New CM, Fuji UM-MA HC, Kodak Min-R M and Kodak EB/RA (for rapid system). And Fuji UR-2, a double-emulsion film, was used as a control. Those sensitometric strips exposed by a sensitometer were processed in the different combinations of developing temperatures ranging from 28 to 36℃, processing times from 45 to 210 sec. Average gradient, relative speed and base plus fog obtained from the measured film characteristiccurves were evaluated for the different developing temperatures and times. Fuji UR-2 was scarcely affected and mammographic films were greatly affected in the different combinations without an increase in base plus fog except EB/RA. In New CM, UM-MA HC and Min-R M, the average gradients and the relative speeds increased as the developing temperature was higher and the developing time was longer, but the increases were limit on the combination of 36℃ and 210 sec in New CM and UM-MA HC. In EB/RA, the average gradients were almost constant and the relative speeds increased slightly like the double-emulsion film. These results suggested that it would bepossible to contribute to dose reduction and advancement of contrast in New CM, UM-MA HC and Min-R M by changing these processing parameters.フィルム処理条件において,現像温度と処理時間に対する影響を4種類のマンモグラフィ用フィルムKonica New CM, Fuji UM-MA HC,Kodak Min-R M,迅速処理用Kodak EB/RAについて調べた｡そして,比較基準用として両面乳剤フィルムFuji UR-2を用いた｡感光計で露光したフィルムを現像温度28～36℃,処理時間45～210秒で処理した｡特性曲線から得られたフィルム特性（平均階調度,相対感度,カブリ濃度）を異なる現像温度,現像時間に対して評価した｡UR-2はほとんど影響を受けず,マンモグラフィ用フィルムは,カブリ濃度が上昇することなく,現像条件の影響を大きく受けた。New CM, UM-MA HC,Min-R Mは現像温度の上昇,処理時間の延長に伴い,平均階調度と相対感度は増加した｡しかし,New CM, UM-MA HCの36℃,210秒で増加は限度に達した｡EB/RAの平均階調度は一定で,相対感度は両面乳剤フイルムと同様にわずかな増加であった｡これらの結果は,New CM, UM-MA HC, Min-R Mにおいて,処理条件を変化させることにより,被曝低減,コントラスト向上に貢献できる可能性を示唆していた｡

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その他リンク： http://search.jamas.or.jp/link/ui/1998146743

記述言語：日本語   出版者・発行元：公益社団法人 日本放射線技術学会  

The effectiveness of the extended-cycle process, in which processing time is longer than the manugacturer's recommendation, was investigated using four mammographic films, Konica New CM, Fuji UM-MA HC, Kodak Min-R 2000, and Kodak Min-R M, Fuji UR-2, a double-emulsion film, was used as a control. The sensitometric strips exposed by a sensitometer were processed in different combinations of developing temperatures ranging from 28 to 36℃, processing times from 45 to 210 sec chemicals, Konica XD-90C, Fuji RD-5 and Kodak RP X-Omat. Those characteristics(average gradient, relative speed, base plus fog)obtained from characteristic curves were evaluated for the different developing temperatures, times and chemicals. Fuji UR-2 was scarcely affected, while mammographic films were greatly affected in the different combinations without an increase in base plus fog. For New CM, UM-MA HC and Min-R M, the average gradient and relative speed increased as developing temperature increased and developing time was extended, but the increases were limited with the combination of 36℃ and 210 sec for New CM and UM-MA HC. For Min-R 2000, the average gradient was almost constant, and the relative speed increased like the other three mammographic films. Changes in average gradient and relative speed due to chemical variations showed increases or decreases from 6% to 9% compared with Konica chemical. These results suggested that the extended-cycle process for the above mammographic films has the possibility to contribute to dose reduction and advancement of contrast on mammography.

DOI： 10.6009/jjrt.KJ00001355420

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記述言語：日本語   出版者・発行元：公益社団法人 日本放射線技術学会  

DOI： 10.6009/jjrt.KJ00001356145

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DOI： 10.1109/NSSMIC.2012.6551821

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DOI： 10.1109/NSSMIC.2012.6551821

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DOI： 10.1109/NSSMIC.2012.6551820

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DOI： 10.1109/NSSMIC.2012.6551823

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記述言語：英語  

We propose a quantitative method to evaluate the ability of adaptive image filters for reducing noise to low-contrast objects in Multi-Detector Row Computed Tomography (MDCT). The digital phantom for evaluating the ability of a nonlinear noise reduction filter to a low-contrast object in a MDCT image was produced. The digital phantom consists of a water phantom image of MDCT and a bar pattern with a known contrast and spatial frequency. The edge-preserving adaptive filter for selectively eliminating noise in low-dose scanning known as the Quantum Denoising System developed by Toshiba Medical Systems was chosen as a nonlinear noise reduction filter for this paper. In this paper, two non-linear noise reduction filters, Q1 and Q2 in QDS were employed. By analyzing the power spectrum (PS) of a digital phantom, the filter performance as regards the contrast and spatial frequency of an object was investigated. The contrast-to-noise ratio from PS could express the feature of the filter briefly. That is, the validity of a filter can be shown based on the combined information of the contrast and spatial frequency of an object. Probably, this simple method will contribute to evaluating various noise reduction filters efficiently. © 2011 IEEE.

DOI： 10.1109/IST.2011.5962206

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記述言語：英語  

To achieve detection of calcifications using magnetic resonance imaging (MRI) for breast cancer screening, we investigated combinations of an echo time (TE) and a high-pass filter size on phase images using a breast phantom. The breast phantom was made from gel area of 0.1 mmol/L gadopentetate dimeglumine and 2.0 wt% agar containing imitation calcifications to simulate calcification in the breast. To use the phase image for calcification assessment, optimization of TE was required since a difference of phase is enhanced at sufficiently long TE. However, longer TE tends to increase the static field inhomogeneity effects. To remove the static field inhomogeneity effects, we employed a high-pass filter processing. Then, several different filter sizes were tested to optimize the visualization of calcification. TE of 48 msec had the highest contrast between imitation calcifications and gel area. The high-pass filter size of 6464 pixels was able to remove efficiently the background phase effects. The high-pass filtered phase image was able to show imitation calcifications as hyperintense areas. Although the limit of detection of imitation calcifications was 1.0 mm, it suggests a possibility that the high-pass filtered phase image is able to use for breast cancer screening and diagnosis without pain by compression or the use of ionizing radiation. © 2011 IEEE.

DOI： 10.1109/IST.2011.5962192

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記述言語：日本語   出版者・発行元：公益社団法人日本放射線技術学会  

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出版者・発行元：Springer Berlin Heidelberg  

DOI： 10.1007/978-3-642-03879-2_103

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記述言語：英語   出版者・発行元：IEEE  

We developed an infrared flat-bed scanner with a transparency unit (IR-4000, iMeasure, Inc.) in order to increase the sensitivity of the measuring density of Radiochromic film, Gafchromic film EBT model. Radiochromic film hay been used for many years as a two-dimensional radiation detector for dosimetry in radiotherapy. One of the commercially available Radiochromic films today is the Gafchromic film EBT model (EBT) manufactured by ISP (International Speciality Products, Wayne, NJ). EBT has the absorption spectrum with a maximum absorption band centered at 636 nm Consequently the response of EBT will be enhanced by measuring with a red light. The transparency unit of IR-4000 for EBT hay a light emitting diode (LED) with a peak wavelength of 630 nm, and was produced by replacing a white light in the transparency unit for the flat-bed scanner (ES-2200, Seiko Epson Corp) with the LEDs. IR-4000 could improve the sensitivity for EBT in all dose ranges However, we had to consider the methods for decreasing noise. We examined for IR-4000 how to keep the high sensitivity and reduce noise. Multiple scans and the reduction of the image resolution by pixel averaging, which was effective in noise reductio?; were employed. IR-4000 is a useful densitometry device to GAFs since optional transparency units which have various single emission spectra are prepared

DOI： 10.1109/IMTC.2008.4547049

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DOI： 10.1109/IMTC.2008.4547228

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出版者・発行元：Springer Berlin Heidelberg  

DOI： 10.1007/978-3-540-36841-0_390

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DOI： 10.1109/IMTC.2006.237101

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記述言語：英語   出版者・発行元：SPIE-INT SOC OPTICAL ENGINEERING  

Radiochromic film has been applied to mapping of dose distributions in radiation therapy. However, this particular RCF product suffers from intrinsic nonuniform response. In this study, we have carefully measured the nonuniformity of unirradiated RCF, and the response of irradiated RCF in pixel-to-pixel as function of various absorbed doses, in order to create a method of predicting the error of irradiated, unirradiated RCF.

DOI： 10.1117/12.716968

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記述言語：英語   出版者・発行元：SPIE-INT SOC OPTICAL ENGINEERING  

We built an estimation system of individual breast density from digital mammograms by using breast tissue equivalent phantoms that are able to change the mixture ratio of adipose and glandular tissue and the thickness. The method was compared with a visual assessment of breast density by the radiologists as a gold standard. The clinical image data set that consisted of 49 mammograms of 21 patients were analyzed. The average of the estimated glandular rate was 35.0%, while varying from 12.0% to 67.0%. This system can apply in clinical practice such as the visual estimation of breast density.

DOI： 10.1117/12.716998

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記述言語：英語   出版者・発行元：SPIE-INT SOC OPTICAL ENGINEERING  

To improve the cost of performance in manufacturing IC packages, it is required to inspect BGA defects in the online process. The problems of image analysis for the detection of defects are the detection accuracy and image processing time according to a line speed of production. Using the X-ray penetration equipment, we have captured images of an IC package to search an abnormal BGA. To get design data for the development of the inspection system, which can be used easily in the surface mount process, we tried to capture the tomographic images utilizing the latest imaging techniques.

DOI： 10.1117/12.716986

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DOI： 10.1109/IMTC.2006.237100

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DOI： 10.1109/IMTC.2006.236935

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

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記述言語：英語   出版者・発行元：WORLD SCIENTIFIC PUBL CO PTE LTD  

This paper deals with the image analysis of defects at BGA for the reliability in PC boards by using X-ray imaging. To assure the manufacturing reliability, an inspection system of BGA is required in the surface mount process. As we can find mostly solder bridge defects, we pay attention to detecting solder bridge in a production line. The problems of image analysis for the detection of defects at BGA solder joints are the detection accuracy and image processing time according to a line speed. To get design data for the development of the inspection system, which can be used easily in the surface mount process, we attempt to measure the shape of BGA based on X-ray imaging.

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記述言語：英語   出版者・発行元：WORLD SCIENTIFIC PUBL CO PTE LTD  

The computer aided-system for the breast density pattern classification was built based on the researches of the objective quantification which converts breast density into glandular rate employing the phantom of the synthetic breast-equivalent resin material, and the subjective quantification of radiologists' visual assessment with the method of analysis of paired comparisons employing the Thurstone-Mosteller model. The system consists of the two processes. In the first process, pixels of a digitized mammogram are converted into glandular rates using the neural network to which the exposure conditions and the breast thickness were inputted. In the second process, the pattern classification and the glandular rate computation were performed taking visual assessment into consideration by the neural network to which feature values of the histogram of the glandular rate image converted into gray level were inputted. As a result of receiver operating characteristics (ROC) analysis estimating the pattern classification reliability to visual assessment in 93 samples, the area A(Z) under ROC curve was 0.95 or more values in each pattern. In the computed glandular rate to visual assessment, the maximum absolute error was 13% and the average absolute error was 3.4%.

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記述言語：日本語   出版者・発行元：岡山大学医学部保健学科  

医療の高度化に伴い,近年では長時間のⅩ線透視を行うInterventional Radiology(IVR)手技が頻繁に行われ,副作用としての難治性放射線皮膚障害例の報告が増加している｡確定的影響である放射線皮膚障害はしきい値を超えると発症し,線量に依存して障害の程度が重篤となるため,患者被曝線量の測定が重要である｡しかし,IVRでは照射部位が多彩で,焦点-皮膚間距離が不安定なため,その測定方法は確立されていない｡本研究では,近年IVR等低エネルギー線量測定用フイルムとして開発されたCAFCHROMIC XR TYPE Tについて性能評価を行い,患者皮膚入射面の被曝線量測定への応用の可能性について検討した｡その結果,線量特性,線質特性,ネット値の安定性に良好な特性を示し,臨床に使用可能であったので報告する｡In recent years, interventional radiology (IVR) using which uses prolomged fluoroscopy has been performed frequently in clinical radiology. Also, reports of radiation skin injuries whose symptoms occur after IVR has been also increasing. These symptoms will become worse if the radiation induced skin injuries are caused by doses which are above the designated threshold, and the grade of injuries are dependent on dose. Therefore, it is important that patient skin dose is measured correctly. But when perfoming IVR, irradiation is complex pricedure, and there is a measurement error with an unfixed source-to-skin distance. So. in this paper, characteristics of GAFCHROMIC XR TYPE T (which are film for low energy X-rays) are performed. Then, they are decided whether the applicationto the skin surface incidence dose measurement whoud be posible. From these results usefull data can be obtainned; for exanmpe film characteristics, energy factors and stability of sensivility.

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その他リンク： http://search.jamas.or.jp/link/ui/2004171081

DOI： 10.1117/12.521903

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DOI： 10.1117/12.521828

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記述言語：英語   出版者・発行元：IEEE  

In the surface mount technology, Ball Grid Array (BGA) has been used in a production of PC boards, because of their excellent characters such as high density of the lead pin pitch, better lead rigidity and self-alignment during re-flow processing. This paper deals with the development of image analysis for the detection of defects at BGA solder joints in PC boards by using X-ray images. In the conventional IC boards, it is possible to detect defects of solder joints by visual inspection, because the lead of IC package is set on its outside. However, we can't detect visually defects at BGA solder joints, because they are hidden under the IC package. In a production line, the inspection of BGA in PC boards depends on the function test of electric circuits in the final process. To improve a cost performance and the reliability of PC boards, an inspection of BGA is required in the surface mount process. Types of defects at BGA solder joints are solder bridge, missing connection, solder voids, open connection and miss-registration of parts. As we can find mostly solder bridge in these defects, we pick up this to detect solder bridge in a production line. The problems of image analysis for the detection of defects at BGA solder joints are the detection accuracy and image processing time according to a line speed of production. To get design data for the development of the inspection system, which can be used easily in the surface mount process, it is important to develop image analysis techniques based on X-ray image data. At the first step of our study, we attempt to detect the characteristics of the solder bridges based on an image analysis.

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DOI： 10.1117/12.521828

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記述言語：英語  

<p>In the surface mount technology, a ball grid array (BGA) has been used in the production of PC boards. This paper deals with the detection of defects at BGA solder joints in PC boards by using X-ray imaging. Types of defects at BGA solder joints are solder bridge, missing connection, solder voids, open connection and misregistration of parts. The problems of image analysis for the detection of defects at BGA solder joints are the detection accuracy and image processing time according to the speed of the production line. To get the design data for the development of the inspection system used in the surface mount process, it is important to develop image analysis techniques based on X-ray image data. At the first step of our study, we attempt to detect the characteristics of the solder bridges based on the image analysis technique. </p>

DOI： 10.1109/ICIT.2002.1189898

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

乳がん発見には, 超音波, MRIなども試みられているが, 今年度から検出精度の高いX線撮影法が国の方針で導入された.しかし, 多数の健康人に対する被曝増加が懸念されている.検診時での被曝線量の推定は欧米のデータにより, 行われているが, 体型の異なる日本人女性を対象としたデータは不足しており, 被検者側からみた被曝線量に対する安全性の検討が必要である.そこで, ファントムに基づいて行われていた被曝線量算定法に, 実際に撮影された乳房X線写真の画像解析手法を組み込み, 個人の受ける被曝線量推定手法を構築した.本システムを用いて臨床実験をしたところ, 欧米の基準を下回る放射線量を使用できる可能性が明らかになつた.

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記述言語：日本語   出版者・発行元：一般社団法人電子情報通信学会  

乳がん発見には, 超音波, MRIなども試みられているが, 今年度から検出精度の高いX線撮影法が国の方針で導入された.しかし, 多数の健康人に対する被曝増加が懸念されている.検診時での被曝線量の推定は欧米のデータにより, 行われているが, 体型の異なる日本人女性を対象としたデータは不足しており, 被検者側からみた被曝線量に対する安全性の検討が必要である.そこで, ファントムに基づいて行われていた被曝線量算定法に, 実際に撮影された乳房X線写真の画像解析手法を組み込み, 個人の受ける被曝線量推定手法を構築した.本システムを用いて臨床実験をしたところ, 欧米の基準を下回る放射線量を使用できる可能性が明らかになつた.

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記述言語：日本語   出版者・発行元：岡山大学医療技術短期大学部  

電子線治療は,体表面またはその近傍に発生する悪性腫瘍の治療にしばしば用いられる治療法である｡電子線はエネルギーに対応した飛程を持っており,飛程を越えると急激に線量は減少する。この性質は腫瘍に一定の線量を照射し,腫瘍後方に存在する決定臓器を保護することができるので,病巣を選択的に治療するのに好都合である｡しかし,照射野内に人体軌部組織より密度の違う物質が存在する場合,散乱,吸収の影響が大きく,電子線線量分布は乱れたものとなる｡今回,人体内にある骨を想定してVolumeの違う骨Phantomを使用して影響を調べたところ,骨幅によって骨後方および断端に線量の乱れが生じることがわかった｡すなわち,骨の中央ではある程度後方に距離が離れると,線量は大きく減少する現象が見られた。また,横方向の線量分布は骨断端近くで一旦線量の減少が見られ,断端を離れると急激に増加する｡したがって,実際の臨床において,Target Volume近くに骨が存在する場合は総線量の決定に際して注意が必要である｡The Electron-beam therapy is often used for the treatment to malignant tumors on the surface or its neighborhood of the body. An electron-beam has the range depended on its energy, and its dose is rapidly decreased at the points beyond the range. This property is available to irradiatinga tumor with leaving the critical organs unexposed. However, we should take notice that the dose-distributions are disordered if materials of various densities are in the irradiation field. In this paper, we examined how the dose-distribution are disordered by using the phantom made from human bones of various volumes. As a result, the peculiar disorders of the dose-distribution due to the difference of the bone width were found at the back and edge of a bone. Moreover, the dose at the edge of a bone was decreased, but the dose at the side of a bone was rapidly increased in the distance position from the bone. It is necessary to take account of that the above peculiar phenomenon affect the total dose for the treatment when bones exist near the target volume in the irradiation field.

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その他リンク： http://search.jamas.or.jp/link/ui/1998084793

記述言語：日本語   出版者・発行元：岡山大学医療技術短期大学部  

胃X線検査の被験者を増やし、検査を円滑に行う上で造影剤である硫酸バリウム懸濁液の飲みにくさが障害の一つとなっている。これを改善する目的で、懸濁液に市販の粉末清涼飲料を混入したところ、64.2％の人が通常のものよりも飲みやすいと答えた。臨床上も造影剤の付着が悪くなったり、胃の蠕動を促進する等の問題は生じず、有用であると考えられた。Barium sulfate suspensions are disliked by many people. This is one of the obstacles to increase persons who consult doctors and to have medical examinations smoothly. We mixed soft drinks into the suspensions to improve this problem. As a result, they were popular among 64.2% people, there were not any clinical troubles that the suspensions did not stick to the mucous membrane of the stomach well, the peristalsis of the sotmach were promoted, and so on. These results suggest that the contrast media containing soft drinks is useful for the X-ray examinations of the stomach.

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その他リンク： http://search.jamas.or.jp/link/ui/1996201037

記述言語：日本語   出版者・発行元：岡山大学医療技術短期大学部  

胸部専用の新しい増感紙／フィルムシステムについて物理的画質特性を測定し、従来のシステムと比較を行った。測定した新システムは、日本コダックのインサイトシステムからHC/IT-1、富士メディカルシステムのADシステムからHG-M/UR-1、コニカのEXシステムからXG-S/ES-C である。従来のシステムとして富士メディカルシステムのHR-4/Super HR-S を使用した。その結果、新システムは22～73％感度は高く、特性曲線においては低濃度部を持ち上げ、最大コントラストは高濃度側にシフトしていた。空間周波数2cycles/mmで相対鮮鋭度を比較すると、新システムが10～30％程度の低下となっていた。ノイズは、濃度1.0で新システムが35～46％の減少となった。以上より、新システムは、縦隔部の濃度を上げ、粒状性の改善を重視した設計となっていることが分かった。The new three screen-film systems, Kodack INSIGHT system HC/IT-1, Fuji AD system HG-M/UR-1, and Konica EX system XG-S/ES-C for chest radiography were evaluated. In addition, the conventional system Fuji HR-4/Super HR-S was measured for comparison with new systems. The evaluation method is as follows. The image quality characteristics, speed, contrast, resolution and granularity were measured. The sensitivity and contrast were determined by measuring the MTF (modulation transfer function) and NCTF (normalized contrast transfer function). The granularity was estimated by measuring the Wiener spectrum. The speed of the new systems were improved by 22% to 73%. The dinsities at the maximum gradient value were shifted to high density (2.0-2.7). However, they had 10% to 30% less resolution. The other hand, the granularities were improved by 21% to 37% at 1.0 density. These results suggested that the emphasis of new systems was put on improving the image quality of mediastinum region, maintaining performance of the conventional system.

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その他リンク： http://search.jamas.or.jp/link/ui/1996188507

記述言語：日本語   出版者・発行元：岡山大学環境管理センター  

Patient dose is important consideration in the radiological examination and our environment regarding radiation. Many studies have been published about patient dose, but those data were classified by each organ or tissue. Actuarially, patient dose should be checked by each examined part of patient and each exposure equipment. In this paper, we measured absorbed dose at the depth of 0-200mm with the Mix-DP phantom. The phantom is made by tissue equivalent meterial and is designed to similitude abdominal part. Percentage Depth Dose (PDD) was calculated from these doses. Three single-phase generators and three three-phases generators were used in this measurement. These measurements were analyzed by each equipment, and consequently the clear difference of PDD between the exposure equipments was not found. As the result, we can estimate patient dose at a random depth by using PDD. Furthermore, we can easily know patient dose from the tube-voltage and current time product by the calculation including PDD.These data are very useful to manager patient dose on radiological diagnosis.

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記述言語：日本語   出版者・発行元：岡山大学医療技術短期大学部  

胃検診の受診者を増やし、検査を円滑に行う上で、造影剤である硫酸バリウム懸濁液の飲みにくさが障害の一つとなっている。これを改善する試みとして、懸濁液に市販の粉末清涼飲料を混入し検討したところ72.1％の人から通常のものよりも飲みやすいという回答を得た。今後、臨床的な検討を加えながら、さらに創意工夫していく必要がある。Barium sulfate suspensions are disliked to drink by many people. That is one of the obstacles to increse person who consult doctors and to have medical examinations smoothly. We mixed soft drinks into the suspensions to improve this problem. As a result they were popular among 72.1% people. We need to study about these suspensions further, adding the clinical matters.

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その他リンク： http://search.jamas.or.jp/link/ui/1995246911

記述言語：日本語   出版者・発行元：岡山大学医療技術短期大学部  

放射線治療の成否は厳密に設定されたTarget Volumeに如何に正確な線量を照射するかによって決まる。治療術式の過程において、最も大きな誤差を生む要因は照射機器である。誤差の少ない治療を目指す第一歩は機器を正確に作動させることであり、日常からの保守点検および整備が必要である。今回、岡山大学附属病院で1976年から1991年までに使用されたリニアックについて、その故障状況を集計し、部位別故障件数、管球の寿命、稼動率などを分析検討した。その結果、故障件数では設置され稼動を始めた1976年、装置の老朽化が進んだ1990、1991年に多かった。部位別集計では加速部に圧倒的に多く、次いで照射口、高圧部の順であった。稼動率は設置年および1987年を除いてはいずれも96％以上とよい結果であった。この結果は全国に稼動している同型の装置の保守点検に役立つものと考える。The Accuracy of radiation dose exposed the rigidly selected target volume is one of significant factors that have an influence upon the efficiency of treatment in the radiotherapy techniques. Therefore, it is necessary to daily maintain and check irradiation equipment for the radiotherapy. For the radiotherapy, the electron linear accelerator, Toshiba LMR-15A, had worked from 1976 to 1991 in Okayama University Hospital. On this study, all records regarding the operating condition were analyzed concerning parts of trouble, life of a tube and operating efficiency for these sixteen years. In a high frequency of trouble, an accelerating structure ranked first, followed by a collimator and a high voltage generator. The operating efficiency was 95% or greater. This report should be helpful to maintain and check a same model in other hosptals.

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その他リンク： http://search.jamas.or.jp/link/ui/1995246810

記述言語：日本語   出版者・発行元：岡山大学医療技術短期大学部  

Utilization of radiation in medical treatment is increasing more and more ; consequently, It becomes more important to estimate exposure dose correctly. Altough there are many reports about exposue dose for patients, most of them merely describe the results of the measurements by parts of the body. Exposure dose differs with equipment, instruments, screen-firm system, contition of radiography, and so on. This paper describes the relation between skin dose and contitions of radiography, and also shows the result of measurement of "TPR" which needs to know the absorbed dose of each organ.

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その他リンク： http://search.jamas.or.jp/link/ui/1995099385

開催年月日： 2020年4月9日 - 2020年4月12日

記述言語：日本語   会議種別：口頭発表（一般）  

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記述言語：英語   会議種別：口頭発表（一般）  

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開催年月日： 2015年11月29日 - 2015年12月4日

記述言語：英語   会議種別：ポスター発表  

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記述言語：英語   会議種別：ポスター発表  

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