著者
安斎 育郎
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.36, no.2, pp.209-225, 1980
被引用文献数
2

Explanations were given as to the characteristic of the MIRD Committtee method for estimating the internal radiation doses due to the radioisotope administration, with special emphasis on the comparison with the method described in the ICRP Publication 2. The method evolved in the MIRD pamphlets have actually developed the accuracy of the calculation of the absorbed energy per disintegration of the radionuclide deposited in various organs, and it became more important to evaluate exactly the cumulated activity A^^〜 in the internal organs concerned. Some examples were selected for explaining how the MIRD pamphlets could practically be used, in which the author emphasized that the precise evaluation of the retention function, especially of its long-term components, was quite important for improving the accuracy of the dose assessment. The method for obtaining the "S" value for the organ mass that is different from that of the MIRD phantom was described. The author finally discussed the problem of estimating the mass of each internal organ out of the anthropometrical parameters such as body height and body weight.
著者
寺下 貴美
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.67, no.4, pp.413-417, 2011

研究方法論においてデータの性質から、数値で表されるデータを量的データ性質や特徴など数値で表せないデータを質的データという2つに分類される。 本稿では、質的データを扱う研究手法である質的研究手法に焦点を絞り、質的研究手法において理解すべき基本的項目を網羅的に紹介する。
著者
西浦 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.66, no.11, pp.1485-1491, 2010-11-22 (Released:2010-11-19)
参考文献数
19
被引用文献数
3 3

Understanding inter-observer variability in clinical diagnosis is crucial for reliability studies. As the statistical measurements of reliability, the kappa statistic and its extensions have been widely adopted in medical research, but it has been discussed that kappa is vulnerable to prevalence and presence of bias. As an alternative robust statistic, AC1 has attracted recent statistical attentions. This article describes fundamental ideas and quantitative features of AC1. The reliability of infrared thermoscanner as an application in detecting febrile patients of pandemic influenza is discussed by means of Monte Carlo simulation. AC1 adjusts chance agreement more appropriately than kappa and is regarded as a more useful measurement for assessing inter-observer agreement, especially when prevalence is small.
著者
小沼 洋治 林 美智子 林 裕晃 西原 貞光
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.3, pp.277-282, 2012-03-20 (Released:2012-03-24)
参考文献数
12
被引用文献数
4

We tried to remove contamination of radioisotope (RI) for an X-ray detector (photostimulable phosphor plate; IP) and verified that our procedure suggested by Nishihara et al. was effective for decontamination. The procedure was as follows. First, the IP was kept for approximately twelve hours, and then it was processed [image (A)] as well as a clinical processing mode. Second, using a wet-type chemical wiper, we scavenged the IP to remove the adhered RI on its surface. Then, once again, the IP was kept for approximately fifteen hours and processed [image (B)] in order to check an effect of decontamination. Finally, the two images of (A) and (B) were analyzed using ImageJ, which can be downloaded as a free software, and a percentage of removal was calculated. The procedure was applied to two IPs using the FCR 5501 plus. In the present case, the percentage of removal was approximately 96%. The removed radioisotopes in the chemical wipers were analyzed by Ge detector. Then, 134Cs and 137Cs were found with activities of 2.9 4.3 Bq and 3.5 5.2 Bq, respectively. For three months after that, we cannot see black spots on the IPs owing to the contamination of the RI and there are no defects caused by decontamination using a wet-type chemical wiper.
著者
宮島 隆一 藤淵 俊王 宮地 優介 立石 哲士 宇野 善徳 天川 一利 大浦 弘樹 折田 信一
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.74, no.4, pp.326-334, 2018 (Released:2018-04-20)
参考文献数
16
被引用文献数
3 4

Medical staffs like radiological technologists, doctors, and nurses are at an increased risk of exposure to radiation while assisting the patient in a position or monitor contrast medium injection during computed tomography (CT). However, methods to protect medical staff from radiation exposure and protocols for using radiological protection equipment have not been standardized and differ among hospitals. In this study, the distribution of scattered X-rays in a CT room was measured by placing electronic personal dosimeters in locations where medical staff stands beside the CT scanner gantry while assisting the patient and the exposure dose was measured. Moreover, we evaluated non-uniform exposure and revealed effective techniques to reduce the exposure dose to medical staff during CT. The dose of the scattered X-rays was the lowest at the gantry and at the examination table during both head and abdominal CT. The dose was the highest at the trunk of the upper body of the operator corresponding to a height of 130 cm during head CT and at the head corresponding to a height of 150 cm during abdominal CT. The maximum dose to the crystalline lens was approximately 600 μSv during head CT. We found that the use of volumetric CT scanning and X-ray protective goggles, and face direction toward the gantry reduced the exposure dose, particularly to the crystalline lens, for which lower equivalent dose during CT scan has been recently recommended in the International Commission on Radiological Protection Publication 118.
著者
森下 雄太 宮地 利明 上田 丞政 清水 満 濱口 隆史 藤原 康博 林 弘之
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.64, no.5, pp.587-590, 2008-05-20 (Released:2008-05-29)
参考文献数
13
被引用文献数
1 1

The purpose of our study was to assess the mechanical effect on tattoo seals and eye makeup caused by a spatial magnetic gradient in the magnetic resonance imaging (MRI) system. Seven kinds of tattoo seals and three kinds of eye makeup, i.e., mascara, eye shadow, and eyeliner were used. On a 3.0-Tesla MRI, we determined these deflection angles according to a method established by the American Society for Testing and Materials (ASTM) at the position that produced the greatest magnetically induced deflection. Eighty-five percent of the tattoo seals showed deflection angles greater than 45 degrees of the ASTM guidelines, and the mascara and eye shadow showed over 40 degrees. This was because these contained ferromagnetic pigments such as an iron oxide, but those translational forces were very small owing to slight mass. However, it is desirable that these should be removed before MRI examination to prevent secondary problems.
著者
加藤 秀起 津坂 昌利 小山 修司 前越 久
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.5, pp.615-623, 1998
参考文献数
16
被引用文献数
1 1

An x-ray spectrum measured by a semiconductor detector is different from the incident x-ray spectrum to the detector, because of distortions caused by energy-dependent responses of the detector and statistical and electrical fluctuations in the signal amplifying process. In this paper, we discuss a method for correcting the statistical and electrical fluctuations of the x-ray spectrum, using the unfolding method with a function based on the Gaussian distribution. Unfolding the measured x-ray spectrum by this method, K-α and K-β characteristic x-rays were clearly separated into two line spectra, and energy resolution was improved. The unfolding method, when used to supplement the stripping method that is generally applied to x-ray spectra correction, will provide enhanced correction of x-ray spectra.
著者
小宮 勲 白坂 崇 梅津 芳幸 橘 昌幸 泉 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.60, no.2, pp.270-277, 2004
参考文献数
20
被引用文献数
12 14

In this study, we investigated the usefulness of the fluorescent glass dosimeter for measuring patient dose. The fluorescent glass dosimeter is constructed of a glass element and its holder. One type has a tin (Sn) filter and the other does not. The characteristics of these two types of fluorescent glass dosimeters were studied in the range of diagnostic X-ray energy. The result was excellent for each characteristic. Directional dependency, however, was recognized in the fluorescent glass dosimeter with tin (Sn) filter. Based on these evaluations, patient skin dose was measured for abdominal interventional radiology and diagnostic digital subtraction angiography using the holder without filter, which is less direction-dependent and eliminates obstructive shadows in radiography and fluoroscopy. The average skin dose of 30 patients for abdominal IVR was 1.17±0.44 Gy (0.51-1.94 Gy), while those for diagnostic DSA examination was 0.54±0.21 Gy (0.15-1.02 Gy). The fluorescent glass dosimeter provides high capability for skin dose measurement. The fluorescent glass dosimeter is also useful for controlling patient dose during IVR procedures.
著者
池口 裕昭 庄内 孝春 渡部 智仁 縄手 満 矢野 竜太朗
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.12, pp.1256-1265, 2020 (Released:2020-12-20)
参考文献数
14

T2 fluid-attenuated inversion recovery (FLAIR) using inversion recovery pulse to suppress cerebrospinal fluid signal needs adequate T1 recovery time after data acquisition, otherwise, the T2-weighted contrast in brain tissue will get lower. Over 10000 ms of repetition time (TR) is recommended for the 1.5 T MR scanner, so it is difficult to shorten the imaging time. We verified whether T2 FLAIR combined with the magnetization transfer contrast (MTC) pulse shows better gray-to-white matter (GM/WM) and lesion-to-normal tissue contrasts even when the TR is shortened compared to the conventional T2 FLAIR. Optimal parameters of the MTC pulse were determined with a self-produced phantom, which modeled on cerebral cortical gray and white matters. GM/WM contrasts of the phantom were measured in T2 FLAIR with the MTC pulse while decreasing TR gradually from 10000 ms to 6500 ms. Although GM/WM contrast of the phantom in T2 FLAIR with the MTC pulse gradually decreased as the TR got shortened, the T2 FLAIR with the MTC pulse of 6500 ms of TR still showed 27% higher contrast than the conventional T2 FLAIR (TR 10000 ms). GM/WM contrast in T2 FLAIR with the MTC pulse was improved also in healthy volunteers, but improvement in thalamo-medullary contrast was less than that of cerebral cortico-medullary and putamino-medullary contrasts. It seems to be because thalamus, which is a deep gray matter, shows a higher MTC effect than other gray matters. Thus, it is necessary to note that the tissue contrast might differ between T2 FLAIR with the MTC pulse and the conventional T2 FLAIR. Because general lesions with an elongated T2 value show lower MTC effect compared to the normal brain tissue, a clinical case with thalamic lesion showed that the lesion-to-normal tissue contrast improved in T2 FLAIR with the MTC pulse of 6500 ms of TR. Although it is necessary to note the difference in contrast between some tissues, T2 FLAIR with the MTC pulse improves GM/WM and lesion-to-normal tissue contrasts even when the TR is shortened compared to the conventional T2 FLAIR, and it enables to shorten the imaging time.
著者
川崎 達哉 加藤 英幸 笠原 哲治 田岡 淳一 梅北 英夫 桝田 喜正
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.3, pp.278-284, 2020 (Released:2020-03-20)
参考文献数
18

This study was designed to clarify the relation between the pressure resistance of an angiographical tube and the amount of contrast medium injected under a connected microcatheter used for interventional radiology (IVR). We investigated the injection pressure and the expansion rate at the center of the tube during contrast enhancement by setting the power injector to 1200 PSI pressure, with 2.0 ml/s injection speed, 10 ml injection volume, 5.0 s injection time, and 0 s rise time for tubes with different pressure resistance performance (low or high). Then we examined the amount of contrast medium material discharged from the microcatheter. The low-pressure resistant tube (less than 140 PSI) injection pressure exceeded the pressure performance. The expansion rate increased to 49%, presenting a risk of rupture. The injection pressure of the high-pressure resistant tube (less than 1200 PSI) was within the pressure-resistance performance. The expansion rate increased to 38%. However, when the contrast medium discharge amount contributing to the image was measured within the injection time under the condition of 10 ml injection for 5.0 s, the former was 2.3 ml and the latter was 4.2 ml. The entire amount was not discharged during the injection period. It became apparent that it is discharged in drips after some time. Results show that the tube expansion caused retention of the contrast medium inside, which decreases the actual amount of the injected contrast medium. From the results, we infer the possibility of preventing reduction of the injected contrast medium amount attributable to expansion.
著者
池口 裕昭 庄内 孝春 巳上 綾 矢澤 夏佳 高橋 正 山田 幸二
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.69, no.1, pp.71-79, 2013-01-20 (Released:2013-01-25)
参考文献数
11
被引用文献数
3 1

Purpose: Homogeneity of static magnetic field (B0) is unstable for head and neck magnetic resonance (MR) examination; consequently, chemical shift selective fat suppression becomes inhomogeneous. There is a commercially available additional pad to attenuate the B0 inhomogeneity, but it is expensive. It has been reported that uncooked rice can be used as a material in the pad, but it has hygienic and weight problems. We searched for a material which can replace the uncooked rice, and evaluated its performance. Method: After filling various materials into the cylindrical phantom, each material was evaluated by image distortion of gradient filed echo and spin echo single-shot echo planar images. A prototype additional pad was made with a material which showed less image distortion in the phantom experiment and is easily available in clinical examination. For comparison, an uncooked rice pad with the same volume was also prepared. Fat suppressed head and neck magnetic resonance imaging (MRI) of normal volunteers were visually compared when the three additional pads, including the commercial product, were used or not. Result: The polystyrene ball bullet (BB bullet) was adopted as a material for the additional pad. The improvement of the fat suppression in the head and neck MRI was almost the same between the three additional pads. BB bullet pad was the lightest. Conclusion: BB bullet can be used as a material of additional pad attenuating the B0 inhomogeneity instead of uncooked rice.
著者
鈴木 千晶 藤崎 賢二 渥美 雄介 竹村 実紀 水野 孝一 永峯 岳樹 天野 智康 山本 英雄 高橋 護
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.73, no.4, pp.273-281, 2017 (Released:2017-04-20)
参考文献数
22

The purpose of this study is to measure the hemodynamics on the effect of Valsalva maneuver aiming at pulmonary thromboembolism (PTE) using 2-dimensional (2D) phase contrast imaging of magnetic resonance image (MRI), Philips Ingenia 3.0-tesla (T). The maximal inspiration reduced the blood flow rate in various degrees at all measurement positions, superior vena cava (SVC), inferior vena cava (IVC), pulmonary artery (PA), ascending aorta (AA), and descending aorta (DA). This result suggests that the contrast effect in the PA might become weak during general PA phase to give a substantial influence of Valsalva maneuver in the condition after maximum inspiration. A contrast-enhanced computed tomography (CT) examination aiming at detection for PTE should be scanned without an advance maximum inspiration.