Nihon Hōshasen Gijutsu Gakkai zasshi最新文献

Size-specific dose estimates(SSDE)算出のためのsize correction factor の検討考虑用于size -specific dose estimates(SSDE)计算的size correction factor

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 2016-09-01 DOI: 10.6009/JJRT.2016_JSRT_72.9.727

Kazufusa Mizonobe, Yuta Shiraishi, Satoshi Nakano, Chiaki Fukuda, O. Asanuma, Kohei Harada, H. Date

{"title":"Size-specific dose estimates(SSDE)算出のためのsize correction factor の検討","authors":"Kazufusa Mizonobe, Yuta Shiraishi, Satoshi Nakano, Chiaki Fukuda, O. Asanuma, Kohei Harada, H. Date","doi":"10.6009/JJRT.2016_JSRT_72.9.727","DOIUrl":"https://doi.org/10.6009/JJRT.2016_JSRT_72.9.727","url":null,"abstract":"American Association of Physicists in Medicine (AAPM) Report No.204 recommends the size-specific dose estimates (SSDE), wherein SSDE=computed tomography dose index-volume (CTDIvol )×size correction factor (SCF), as an index of the CT dose to consider patient thickness. However, the study on SSDE has not been made yet for area detector CT (ADCT) device such as a 320-row CT scanner. The purpose of this study was to evaluate the SCF values for ADCT by means of a simulation technique to look into the differences in SCF values due to beam width. In the simulation, to construct the geometry of the Aquilion ONE X-ray CT system (120 kV), the dose ratio and the effective energies were measured in the cone angle and fan angle directions, and these were incorporated into the simulation code, Electron Gamma Shower Ver.5 (EGS5). By changing the thickness of a PMMA phantom from 8 cm to 40 cm, CTDIvol and SCF were determined. The SCF values for the beam widths in conventional and volume scans were calculated. The differences among the SCF values of conventional, volume scans, and AAPM were up to 23.0%. However, when SCF values were normalized in a phantom of 16 cm diameter, the error tended to decrease for the cases of thin body thickness, such as those of children. It was concluded that even if beam width and device are different, the SCF values recommended by AAPM are useful in clinical situations.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"98 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115762970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The Pleasure of Studying New Knowledge, etc. 学习新知识的乐趣等。

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 2016-02-01 DOI: 10.6009/jjrt.2016_JSRT_72.2.183

I. Maehata, Takatoshi Usuda, Takumi Murakami, Fumitaka Sato

引用次数: 0

「錯視現象」が胸部CT画像の気胸の診断能に及ぼす影響 : 視覚心理学的シミュレーションによる実証 “错觉现象”对胸部CT图像气胸诊断功能的影响:视觉心理学模拟实验

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 2008-10-20 DOI: 10.6009/JJRT.64.1206

Shuichi Henmi

{"title":"「錯視現象」が胸部CT画像の気胸の診断能に及ぼす影響 : 視覚心理学的シミュレーションによる実証","authors":"Shuichi Henmi","doi":"10.6009/JJRT.64.1206","DOIUrl":"https://doi.org/10.6009/JJRT.64.1206","url":null,"abstract":"Some cases have been reported in which an optical illusion of lightness perception influences the detectability in diagnosis of low-density hematoma in head CT images in addition to the visual impression of the photographic density of the brain. Therefore, in this study, the author attempted to compare the detectability in diagnosis for chest images with pneumothorax using visual subjective evaluation, and investigated the influence of optical illusion on that detectability in diagnosis. Results indicated that in the window setting of lung, on such an occasion when the low-absorption free space with pneumothorax forms a crescent or the reduced lung borders on the chest-wall, an optical illusion in which the visual impression on the difference of the film contrast between the lung and the low-absorption free space with pneumothorax was psychologically emphasized when contrast was observed. In all cases the detectability in diagnosis for original images with the white thorax and mediastinum was superior to virtual images. Further, in case of the virtual double window setting of lung, thorax, and mediastinum, under the influence of the difference in the radiological anatomy of thorax and mediastinum as a result of the grouping theories of lightness computation, an optical illusion different from the original images was observed.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"102 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127167580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

外科的手技を伴う非血管性IVRでの術者の手指の被ばく : Under-table tube方式とOver-table tube方式の比較外科手术非血管性IVR下的受术者手指辐射:Under-table tube和Over-table tube的比较

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 2008-10-20 DOI: 10.6009/JJRT.64.1235

努中野

{"title":"外科的手技を伴う非血管性IVRでの術者の手指の被ばく : Under-table tube方式とOver-table tube方式の比較","authors":"努中野","doi":"10.6009/JJRT.64.1235","DOIUrl":"https://doi.org/10.6009/JJRT.64.1235","url":null,"abstract":"In non-vascular interventional radiology (IVR) such as percutaneous transhepatic cholangio-drainage (PTCD) and nerve block, the operator’s hands are irradiated in primary x-ray field. In Over-table tube fluoroscopy system, operator’s hands inevitably are exposed excessively to intensive primary radiation, whereas in the Under-table tube fluoroscopy system, they are irradiated weakly by attenuated radiation through the patient’s body. For this reason, the dose to the operator’s hands in Under-table tube fluoroscopy is less than in Over-table tube fluoroscopy. This paper proposes general formulas for estimating the absorbed dose on the operator’s hands in two types of fluoroscopy. The formulas include factors affecting the absorbed dose on the operator’s hand; distance from source to the operator’s hands, x-ray transmittance of the patient and patient’s bed, and back-scatter factor of the patient. Absorbed dose to imitated operator’s hand was measured and estimated by formulas in two types of fluoroscopy for various phantom thicknesses and two field sizes using an ionization chamber. The difference between estimated absorbed dose and measured absorbed dose was less than 10%.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116949144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

定量的PET測定に用いる測定器の信頼性－電離箱式放射能測定装置，ウェル型シンチレーションカウンタ，持続動脈血中放射能濃度測定器およびPET装置の評価－定量PET测定所使用的测定器的可靠性-电离箱式放射能测定装置，阱型消辐射计数器，持续动脉血中放射能浓度测定器及PET装置的评价-

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 2008-10-20 DOI: 10.6009/JJRT.64.1227

圭一松本, 誠一山本, 康弘和田, 敬二清水, 研也村瀬, 道雄千田

{"title":"定量的PET測定に用いる測定器の信頼性－電離箱式放射能測定装置，ウェル型シンチレーションカウンタ，持続動脈血中放射能濃度測定器およびPET装置の評価－","authors":"圭一松本, 誠一山本, 康弘和田, 敬二清水, 研也村瀬, 道雄千田","doi":"10.6009/JJRT.64.1227","DOIUrl":"https://doi.org/10.6009/JJRT.64.1227","url":null,"abstract":"Purpose: Positron emission tomography (PET) is a powerful tool for measuring in vivo functions such as blood flow, metabolism, enzyme activity, receptors, and transporters. However, plural measuring instruments (i.e., the dose-calibrator, the auto well gamma counter, the continuous blood sampling system) are necessary for the quantitative PET measurement as well as the PET scanner. The purpose of this study was to investigate the reliability of plural measuring instruments from the maintenance data for 6 years. Methods: Four kinds of measuring instrument were evaluated: a dose-calibrator (CAPINTEC, CRC-15R), an auto well gamma counter (ALOKA, ARC-400), a continuous blood sampling system (ESPEC Techno, PH type), and a dedicated PET scanner (Siemens, ECAT EXACT HR+). We examined whether the initial performance for system sensitivity is maintained. The reliability of the PET scanner was evaluated from the value of mean time between failures (MTBF) for each part of the system obtained from the maintenance data for 6 years. Results: The sensitivity of a dose-calibrator and an auto well gamma counter were maintained virtually constant during the 6 years, but the sensitivity of a continuous blood sampling system was 0.1±3.2%. The sensitivity of a PET scanner was decreased to 92.3% of the initial value. Fifty-one percent of the problems with the PET scanner were for detector block (DB) and analog processor (AP) board. The MTBF of DB and AP board module were 199 and 244 days, respectively. The MTBF of the PET scanner was 56 days. Conclusion: The performance of three measuring instruments, excepting the PET scanner, was relatively stable. The reliability of the PET scanner strongly depends on the MTBF of the DB and AP board. For quantitative PET measurement, it is effective to evaluate the reliability of the system and to make it known to the users.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116308736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

ビスマスシートを用いたcomputed tomography fluoroscopyにおける術者被ばくと画質の評価利用铋片的computed tomography fluoroscopy评估受术者辐射画质

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 1900-01-01 DOI: 10.6009/JJRT.2016_JSRT_72.11.1137

Keisuke Takiguchi, Atsushi Urikura, Tsukasa Yoshida, Kenichi Hirosawa, Takahiro Ito, Yoshihiro Nakaya

{"title":"ビスマスシートを用いたcomputed tomography fluoroscopyにおける術者被ばくと画質の評価","authors":"Keisuke Takiguchi, Atsushi Urikura, Tsukasa Yoshida, Kenichi Hirosawa, Takahiro Ito, Yoshihiro Nakaya","doi":"10.6009/JJRT.2016_JSRT_72.11.1137","DOIUrl":"https://doi.org/10.6009/JJRT.2016_JSRT_72.11.1137","url":null,"abstract":"OBJECTIVE: The purpose of this study was to assess the dose reduction and the image quality using bismuth sheets during the computed tomography fluoroscopy (CTF). MATERIALS AND METHODS: The bismuth sheets of 1-mm thick were put on the upper mylar ring to reduce the frontal X-ray. The dose rates of an operator were measured using a torso phantom in the patient position during the CTF. The torso phantom was set on the gantry rotation center (center) and the lower position from the center (off-center). The image quality of the CTF image was assessed using an original phantom that mimics the normal liver parenchyma and the low attenuation lesions. The image contrast and contrast-to-noise ratio (CNR) were compared with and without the bismuth sheets. RESULTS: The bismuth sheets reduced the dose rate of the operator, regardless of whether the torso phantom was set at the center or the off-center. The reduction rate of exposure at the center and the off-center were 42.3% and 34.5%, respectively. There were no significant differences in the image contrast and the CNR, although the bismuth sheets increased the CT values of the liver parenchyma and the low attenuation lesions. CONCLUSION: The bismuth sheets were effective for the reduction of exposure to the operator without degrading the image quality of CTF images.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"376 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115908076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

小児腹部CT 検査における自動露出制御の一手法―年齢および腹部サイズを考慮した標準偏差(SD)値および管電流値の設定法― 儿童腹部CT检查的一种自动曝光控制方法——基于年龄和腹部尺寸的标准差(SD)值和管电流值的设定方法——

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 1900-01-01 DOI: 10.6009/JJRT.2017_JSRT_73.1.33

研古屋, 真志秋山, 敦史南部, 裕鈴木, 裕介長谷部

{"title":"小児腹部CT 検査における自動露出制御の一手法―年齢および腹部サイズを考慮した標準偏差(SD)値および管電流値の設定法―","authors":"研古屋, 真志秋山, 敦史南部, 裕鈴木, 裕介長谷部","doi":"10.6009/JJRT.2017_JSRT_73.1.33","DOIUrl":"https://doi.org/10.6009/JJRT.2017_JSRT_73.1.33","url":null,"abstract":": We aimed to apply the pediatric abdominal CT protocol of Donnelly et al. in the United States to the pediatric abdominal CT-AEC. Examining CT images of 100 children, we found that the sectional area of the hepatic portal region (y) was strongly correlated with the body weight (x) as follows: y=7.14x + 84.39 (correlation coefficient=0.9574). We scanned an elliptical cone phantom that simulates the human body using a pediatric abdominal CT scanning method of Donnelly et al. in, and measured SD values. We further scanned the same phantom under the settings for adult CT-AEC scan and obtained the relationship between the sectional areas (y) and the SD values. Using these results, we obtained the following preset noise factors for CT-AEC at each body weight range: 6.90 at 4.5-8.9 kg, 8.40 at 9.0-17.9 kg, 8.68 at 18.0-26.9 kg, 9.89 at 27.0-35.9 kg, 12.22 at 36.0-45.0 kg, 13.52 at 45.1-70.0 kg, 15.29 at more than 70 kg. From the relation between age, weight and the distance of liver and tuber ischiadicum of 500 children, we obtained the CTDIvol values and DLP values under the scanning protocol of Donnelly et al. Almost all of DRL from these values turned out to be smaller than the DRL data of IAEA and various countries. Thus, by setting the maximum current values of CT-AEC to be the Donnelly et al.'s age-wise current values, and using our weight-wise noise factors, we think we can perform pediatric abdominal CT-AEC scans that are consistent with the same radiation safety and the image quality as those proposed by Donnelly et al.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"84 20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115503218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Gd-EOB-DTPAを用いたMRI検査の動脈相を想定したシミュレーションによるブラーリングのMTF測定假设使用Gd-EOB-DTPA的MRI检查的动脉相，通过模拟测定颤动的MTF

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 1900-01-01 DOI: 10.6009/JJRT.2016_JSRT_72.11.1169

Masashi Kikuchi, N. Hayashi, Kazuma Yarita, Kozue Sakata, Koichi Ujita, S. Matsuda, Y. Teduka

{"title":"Gd-EOB-DTPAを用いたMRI検査の動脈相を想定したシミュレーションによるブラーリングのMTF測定","authors":"Masashi Kikuchi, N. Hayashi, Kazuma Yarita, Kozue Sakata, Koichi Ujita, S. Matsuda, Y. Teduka","doi":"10.6009/JJRT.2016_JSRT_72.11.1169","DOIUrl":"https://doi.org/10.6009/JJRT.2016_JSRT_72.11.1169","url":null,"abstract":"During the arterial phase acquisition of Gd-EOB-DTPA examinations, use of a small volume of the Gd-EOB-DTPA may make it difficult the encoding center of the k-space, and produce blurring. The previous studies revealed the encoding technique of the k-space was one of the most important reasons. However, there is no report to discuss the reasons with quantitative evaluations. The purpose of this study was to quantitatively evaluate the characteristics of the artifacts using different k-space encoding techniques (centric-view ordering (CVO) and sequential-view ordering (SVO)) for liver dynamic MRI in computer simulation study. This simulation study consists of the following steps. First of all, the creation of a time intensity curve, and original simulation images at certain points among the one phase dynamic scanning. Secondly, creation-simulated MR echo data from the created original images using FFT, and encoding simulated k-space using the simulated MR echo data. Finally, a reconstruction of simulated dynamic MR images from the simulated k-space, and to evaluate each simulated MR images, we measured modulation transfer functions (MTFs) from the bar patterns of the reconstructed images. The results of the CVO simulation indicated that the bar patterns were blurring compared to the images encoded by the SVO. The results of the SVO simulation indicated that the bar patterns were not enhanced at late scan timings. In addition, the results of MTFs indicated that there was no edge enhancement at all scan timings and both encoding techniques. In conclusion, it is possible to quantitatively evaluate the characteristics of artifacts using MTF, which was measured by the bar patterns, in liver dynamic MRI.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"194 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129607236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

67Ga-SPECT 定量法開発に向けた基礎的検討 67ga - spect定量法面向开发的基础探讨

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 1900-01-01 DOI: 10.6009/JJRT.2017_JSRT_73.1.12

Kensuke Nakanishi, Reiki Sakata, Akihiro Takaki, Yutaka Nakasone, Masataka Kadota, Shigeki Ito

{"title":"67Ga-SPECT 定量法開発に向けた基礎的検討","authors":"Kensuke Nakanishi, Reiki Sakata, Akihiro Takaki, Yutaka Nakasone, Masataka Kadota, Shigeki Ito","doi":"10.6009/JJRT.2017_JSRT_73.1.12","DOIUrl":"https://doi.org/10.6009/JJRT.2017_JSRT_73.1.12","url":null,"abstract":"PURPOSE 67Ga-single photon emission computed tomography (SPECT) images vary according to the imaging time and image display methods. The calculation of an index, such as the standardized uptake value used in positron emission tomography, from 67Ga-SPECT images would enable the accurate evaluation of the region of accumulation. The purpose of this study was to elucidate the conversion formula, the lower detection limit (LDL), and recovery coefficient (RC) for quantifying the radiation concentration in the 67Ga accumulation site. METHODS After chronologically obtaining SPECT/CT images at a radiation concentration of 1.0-442.4 kBq/mL with 27 bottles (diameter: 48 mm, 100 mL), the radiation concentration conversion formula was calculated using the successive approximation reconstruction method. The conversion coefficient was then calculated from the relationship between the count rate and the radiation concentration, and the LDL was determined. To compensate for the partial volume effect, the recovery curve was calculated using the mean SPECT count for six bottles (diameter: 9, 18, 29, 38, 48, and 94 mm). RESULTS There was a linear relationship between the radiation concentration and the count rate with a good correlation (r=0.99). The LDL was 1.0 kBq/mL. The recovery curve reached a plateau at a diameter of at least 48 mm. CONCLUSION The calculation of the absorbed dose index was possible using the radiation concentration conversion formula and the RC.","PeriodicalId":393304,"journal":{"name":"Nihon Hōshasen Gijutsu Gakkai zasshi","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115226517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

頸動脈プラークを対象とした至適T1 強調画像の検討‐異なるMRI 装置間で定量評価に与える影響について‐ 以颈动脉斑块为对象的至适T1强调图像的研究-不同MRI设备之间对定量评估的影响-

Nihon Hōshasen Gijutsu Gakkai zasshi Pub Date : 1900-01-01 DOI: 10.6009/JJRT.2017_JSRT_73.2.104

Takanori Naka, Mitsuyuki Takahashi, Koutarou Takeda, Tarou Igarashi, Tetsukazu Hondera

引用次数: 0