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Volume 48, Issue 11
Displaying 1-33 of 33 articles from this issue
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Article type: Cover
1992 Volume 48 Issue 11 Pages Cover5-
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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Article type: Index
1992 Volume 48 Issue 11 Pages Toc5-
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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Article type: Index
1992 Volume 48 Issue 11 Pages Toc6-
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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Article type: Appendix
1992 Volume 48 Issue 11 Pages i-xvi
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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Article type: Appendix
1992 Volume 48 Issue 11 Pages xvii-xx
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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M. HATAGAWA, M. INOUE, M. SYOHGAKI, K. KISHIMOTO, R. YOSHIDAArticle type: Article
1992 Volume 48 Issue 11 Pages 1932-1938
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSThe modulation transfer function (MTF) has been used for evaluation of radiographic image quality. However, in digital radiographic system such as a computed radiography (CR), the MTF can not be used in the same way of an analog system for evaluation because digital system is not shift-invaliant system. Then, we suggest the "MTF_<final>" which includes geometric unsharpness, detector unsharpness, unsharpness of the sampling aperture and unsharpness of the display (Laser-printer). It is an analog component in the digital system and in agreement with the definition of the MTF. Furthermore, an overall aliasing has to be used with MTF_<final> for evaluating the digital system because it is one of the important factors of the digital system. The MTF_<final> and the overall aliasing can be obtained from the overall MTFs of the center alignment and the shifted alignment.View full abstractDownload PDF (632K) -
SYUICHI YAMAUCHI, HIROSHI FUJITA, JUNJI MORISHITA, TSUYOSHI FUJIKAWA, ...Article type: Article
1992 Volume 48 Issue 11 Pages 1939-1944
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSSources of noise in a computed radiography (CR) were investigated by measuring three different Wiener spectra (WS) : (1) laser printer Wiener spectra including CR film, (2) Wiener spectrum of CR film (single emulsion), and (3) overall Wiener spectra. To measure the noise contributed by the laser printer, "image data" (i.e., image having a constant pixel value) were produced on a personal computer and were sent to the laser printer in the CR system. The noise level of laser printer was comparable to that of the CR film at low spatial frequencies (<4 cycles/mm), but the noise level at high spatial frequencies (>4 cycles/mm) was higher than that of the film. Laser printer Wiener spectra obtained in the perpendicular direction relative to the laser beam scanning direction were comparable at low spatial frequencies, but greater at high spatial frequencies, to those obtained in the parallel direction. And a spectral peak around 10 cycles/mm was obtained in the Wiener spectrum in the perpendicular direction. The peak is caused mainly by a banding artifact. Overall Wiener spectra in the parallel and perpendicular directions show the same tendency as those of the laser printer, but the noise level of the overall Wiener spectrum was increased mainly by X-ray quantum mottle at low spatial frequencies. In conclusion, the noise of laser printer greatly increases the overall Wiener spectrum at high spatial frequencies.View full abstractDownload PDF (564K) -
YOSHIFUMI KAWAMURA, ICHIROH MISAWA, YUMIKO YAMADAArticle type: Article
1992 Volume 48 Issue 11 Pages 1945-1951
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSA newly-developed ^<99m>Tc-MIBI was studied regarding its detectability and assessment of myocardial blood flow maldistribution in comparison with ^<201>TlCl in 9 patients with an ischemic heart disease and one patient with III°AV block. Using the polar mapping display generated from the exercise or resting SPECT image data, visual estimation of traces distribution (normal (N), reduced-uptake (R) and defect (D)) were done segmentally. In 10 cases (120 segments), the coincidence of the estimation (N, R and D) between ^<99m>Tc-MIBI and ^<201>TlCl images was 92.5%. Moreover, mean and cumulative counts in ^<99m>Tc-MIBI images were highly comparable in each segment with those in ^<201>TlCl images, although 1 out of 10 cases showed significantly lower values of the segrental mean and cumulative counts in ^<99m>Tc-MIBI images than in the ^<201>TlCl images. In conclusion, ^<201>TlCl and ^<99m>Tc-MIBI yielded comparable data in both the visual and quantitative evaluation in 9 of the 10 cases, suggesting that ^<99m>Tc-MIBI allows to assess regional myocardial blood flow distribution almost equally to ^<201>TlCl.View full abstractDownload PDF (534K) -
ATSUHIKO TOGASHI, KOUICHI HOSHI, RYO KAYAMORIArticle type: Article
1992 Volume 48 Issue 11 Pages 1952-1956
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSX-rays were irradiated to a rod-type glass-sealed element of a thermoluminescence dosimeter (TLD), then the thermoluminescent value was measured on both sides of the X-ray incident and passage surfaces of the element. In view of the observed decrease in the value by 2〜15% on the side of the latter surface compared with the former, It is important for measurement of values having a small coefficient in the variation on diagnostic X-rays to make on a basis of the unification of photometric surfaces. The rate of the above decrease depends on the X-ray tube voltage and energy sensitivity correction filter attached to the element. Next, X-rays were irradiated to a TLD element using two kinds of filters (C and F type), then the relationship between the sensitivity ratio of these filters and the X-ray tube voltage were examined. As a result, we confirmed that a simple measurement of the effective energy for the diagnostic X-rays related to the sensitivity ratio and the incident energy curve with a combination of C and F filter types.View full abstractDownload PDF (517K) -
TAKAYUKI HASEGAWA, MASAYUKI TSUDA, MAKOTO SEO, HIDEHARU TODAKA, KENJI ...Article type: Article
1992 Volume 48 Issue 11 Pages 1957-1963
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSDosimetry data are presented for the 18 MV photon beam of a Varian Clinac 2100C dual energy linear accelerator. The clinical parameters of tissue-peak ratio (TPR), buildup region and surface dose, beam flatness and symmetry, isodose curves, dose rate dependence are discussed to 18 MV photon beam data. For the dose distribution of parallel opposed field with 18, 6, 10 MV related to this paper. We obtained 0.782 for the ionization ratio and 18.1 MV for the nominal energy with AAPM guidelines. Depth of the maximum dose for a 10×10cm^2 field at 100cm source-chamber distance (SCD) was 3.8cm. The relative surface dose increase with field size from 19.9% for a 5×5(cm)^2 field to 55.4% for a 40×40(cm)^2 field.View full abstractDownload PDF (596K) -
Y. HIGASHIDA, N. MORIBE, Y. HIAI, N. KATSUDA, S. DODANUKI, Y. HIRATA, ...Article type: Article
1992 Volume 48 Issue 11 Pages 1964-1970
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSWe have measured the physical imaging properties, such as absolute speeds, modulation transfer functions (MTFs), and Wiener spectra of a large number of screens with calcium tungstate (blue system) and rare earth (green system) phosphor materials used in Japan. We also analyzed systematically the potential of clinical applications of the blue and green systems by taking into account the relationships regarding absolute speed, MTF, and Wiener spectrum. The results have showed that the blue screen systems generally have higher resolution properties than the green systems at the level of comparable speed. However, noise properties were improved by the use of green screen systems at the same speed. These measurement and analysis are very useful in facilitating the proper selection of screen-film system in diagnostic radiology.View full abstractDownload PDF (718K) -
NOBORU FUKUSHIMA, KOUJI IKEDA, YASUHIRO KOBAYASHI, MUTSUMI IKEDA, TETS ...Article type: Article
1992 Volume 48 Issue 11 Pages 1971-1975
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSWe tried a new technique for visualization of vessels and other regions of interest using an ultrafast MRI, iversion recovery snapshot FLASH (Turbo-FLASH) sequence with Gd-DTPA dynamic study. Examinations were performed by a SIEMENS magnetom 1.5T. imager with Turbo-FLASH sequence (TI, 300 msec. ; TR, 7 msec. ; TE, 3 msec. ; flip angle, 8 deg. ; Matrix, 128×128 ; section thickness, 10mm〜20mm ; measurement time, 1sec. per section). Following the injection of Gd-DTPA (0.1mmol/kg), serial images including the region of interest with gapless slice sections were acquired. Acquired images were processed by the maximum intensity projection technique. In conclusion, this technique is valuable to suitable visualizing the vessels and other regions of interest.View full abstractDownload PDF (1458K) -
[in Japanese], [in Japanese]Article type: Article
1992 Volume 48 Issue 11 Pages 1976-1978
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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[in Japanese]Article type: Article
1992 Volume 48 Issue 11 Pages 1979-1984
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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Article type: Appendix
1992 Volume 48 Issue 11 Pages 1984-
Published: November 01, 1992
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[in Japanese]Article type: Article
1992 Volume 48 Issue 11 Pages 1985-1990
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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SYOUSUKE KATO, HISASHI YOSHITA, MAKOTO KURANISHI, HAJIME ITOH, KOUICHI ...Article type: Article
1992 Volume 48 Issue 11 Pages 1991-1996
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSAiming at the realization of PACS, a study was conducted on the present state of, and various problems associated with, X-ray film digitization using a He-Ne laser-type film digitizer. Image quality was evaluated physically and clinically. With regard to the gradation specificity, the linear specificity was shown in a dynamic range of 4 figures. With regard to resolution specificity, visual evaluation was performed using a Hawlet Chart, with almost no difference being found between the CRT and laser printer output images and the decrease in resolution becoming more pronounced as the sampling pitch became greater. Clinical evaluation was performed with reference to the literature. The general evaluation of the clinicians was that although there was some deterioration for all of the shadows, (I have read this many times, but can't understood the last part.) by performing each of the kinds of image-processing enhancement of diagnostic ability was achieved, with a diagnosis being possible. The problem of unhindered diagnosis due to the development of artifacts from optical interference of the grid images projected onto the clinical pictures and digitizer sampling pitch was studied. As countermeasures, the use of a highdensity grid and adoption of a low-pass filter were useful in impeding the development of artifacts. Regarding the operating problems, the inputting of index information requires a considerable number of manhours and a method of automatic recognition from digital data was introduced to overcome this problem. As future prospects, the concepts of a practical system of X-ray film digitization and a film-screen system adapted to digitization were described.View full abstractDownload PDF (1025K) -
KAZUHIRO MASUDAArticle type: Article
1992 Volume 48 Issue 11 Pages 1997-2002
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSDigitization of fluoroscopic images has been developed for the digital cine imaging system as a result of the computer technology, television technology, and popularization of interventional radiology. Present digital cine imaging system is able to offer images similar to cine film because of the higher operatability and better image quality with the development of interventional radiology. As a result, its higher usefulness for catheter diagnosis examination except for interventional radiology was reported, and the possibility of having filmless cine is close to becoming a reality. However, several problems have been pointed out, such as spatial resolution, time resolution, storage and exchangeability of data, disconsolidated viewing functions, etc. Anyhow, digital cine imaging system has some unresolved points and lots the needs to be discussed. The tendency of digitization is the passage of the time and we have to promote a study for more useful digital cine imaging system in team medical treatment which centers on the patients.View full abstractDownload PDF (629K) -
YASUO OKUYAMAArticle type: Article
1992 Volume 48 Issue 11 Pages 2003-2009
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSThe current status and remaining problems of digital image processing in nuclear medicine were discussed. Digitalization of nuclear medicine images has made it possible, in conjunction with computers, to obtain new information (Fourier analysis, Factor analysis, etc.) with added value from images, in place of the fixed concepts that had formerly been drawn only from images. However, the basis of this technology is the special QC and QA of nuclear medicine examinations, and those techniques have not yet been adequately established. The advantage of digitalization is the flexibility that comes from the program, but the element of the subjectivity of each individual plays a large role, and it can be said that there is also the risk that the logic of image diagnosis established to date will be destroyed. Accordingly, the creation of digital image processing techniques with specifications will give birth to standardized digital nuclear medicine images, and these developments will certainly lead to progress in nuclear medicine diagnosis. In addition, in comparison with other modalities, the field of nuclear medicine involves a lesser amount of information, and this simplifies the digitalization of images. At present, equipment is being designed and developed with incorporation of the concept of a work station. A serious problem that remains in this field is the standardization of image transmission. In summary, the main problem that must be solved in the field of nuclear medicine examinations is the establishment of QC and QA methods and practical algorithms for the software. It is hoped that there will be open access to information, etc., related to the software.View full abstractDownload PDF (1044K) -
NAGAAKI OHYAMAArticle type: Article
1992 Volume 48 Issue 11 Pages 2010-2015
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSImage processing is being widely used in the medical field and already has become very important, especially when used for image reconstruction purposes. In this paper, it is shown that image processings can be classified into 4 categories : passive, active, intelligent and visual image processing. These 4 classes are explained at first through the use of several examples. The results shows that the passive image processing does not give better results than the others. Intelligent image processing, then, is addressed, and the simulated annealing method is introduced. Due to the flexibility of the simulated annealing, formulated intelligence is shown to be easily introduced in an image reconstruction problem. As a practical example, 3D blood vessel reconstruction from a small number of projections, which is insufficient for conventional methods to give good reconstruction, is proposed, and computer simulation clearly shows the effectiveness of simulated annealing method. Prior to the conclusion, medical file systems such as IS & C (Image Save and Carry) is pointed out to have potential for formulating knowledge, which is indispensable for intelligent image processing. This paper concludes by summarizing the advantages of simulated annealing.View full abstractDownload PDF (652K) -
YUTAKA ANDOArticle type: Article
1992 Volume 48 Issue 11 Pages 2016-2022
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSFor the PACS (picture archiving and communication system), large strage capacity recording media and a fast data transfer network are necessary. When the PACS are working, these technology requirements become an large problem. So we need image data compression having a higher recording efficiency media and an improved transmission ratio. There are two kinds of data compression methods, one is reversible compression and other is the irreversible one. By these reversible compression methods, a compressed-expanded image is exactly equal to the original image. The ratio of data compression is about between 1/2 and 1/3. On the other hand, for irreversible data compression, the compressed-expanded image is a distorted image, and we can achieve a high compression ratio by using this method. In the medical field, the discrete cosine transform (DCT) method is popular because of the low distortion and fast performance. The ratio of data compression is actually from 1/10 to 1/20. It is important for us to decide the compression ratio according to the purposes and modality of the image. We must carefully select the ratio of the data compression because the suitable compression ratio alters in the usage of images for education, clinical diagnosis and reference.View full abstractDownload PDF (1221K) -
MASAOMI TAKIZAWAArticle type: Article
1992 Volume 48 Issue 11 Pages 2023-2029
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSDiagnostic image management system, such as PACS, will radically change the way of carrying out radiology and patient care in hospitals. A typical PACS can be interfaced with other imaging systems such as CTs, and with a standardization of data communication, it becomes possible to communicate between numerous devices including hospital information systems. The ACR-NEMA and MIPS standard promote communication of digital image information, regardless of the source format of the device set up by the manufactrurer, facilitate the development and expansion of PACS and hospital information system, allowing the creation of diagnostic information databases. Although such standardization is available, they are not widely used in hospitals yet. This paper described that the essential functions regarding the ACR-NEMA and MIPS standard, and their problems inherent under the current standardization.View full abstractDownload PDF (787K) -
YASUHIKO TOHYAMAArticle type: Article
1992 Volume 48 Issue 11 Pages 2030-2032
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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YUJI KAGAArticle type: Article
1992 Volume 48 Issue 11 Pages 2033-2035
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSRotato-Stereography, new angiographical method, equipped with a digital angiography system has remarkable advantages and clinical usefulness. Three dimensional vascular structure can be easily recognized, because arteries and veins are displayed as rotational movie at real time on TV monitor. We summarized the present state and discussed problems of the rotato-stereography which seems to be one of the most important methods of digital anigography.View full abstractDownload PDF (286K) -
MAKOTO KURANISHIArticle type: Article
1992 Volume 48 Issue 11 Pages 2036-2038
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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[in Japanese], [in Japanese], [in Japanese], [in Japanese]Article type: Article
1992 Volume 48 Issue 11 Pages 2039-
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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[in Japanese], [in Japanese]Article type: Article
1992 Volume 48 Issue 11 Pages 2040-2041
Published: November 01, 1992
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Article type: Appendix
1992 Volume 48 Issue 11 Pages 2042-2045
Published: November 01, 1992
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Article type: Appendix
1992 Volume 48 Issue 11 Pages 2045-2048
Published: November 01, 1992
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Article type: Appendix
1992 Volume 48 Issue 11 Pages 2049-2051
Published: November 01, 1992
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Article type: Appendix
1992 Volume 48 Issue 11 Pages 2051-
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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Article type: Appendix
1992 Volume 48 Issue 11 Pages 2051-
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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Article type: Cover
1992 Volume 48 Issue 11 Pages Cover6-
Published: November 01, 1992
Released on J-STAGE: June 29, 2017
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