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Volume 49, Issue 1
Displaying 1-27 of 27 articles from this issue
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Article type: Cover
1993 Volume 49 Issue 1 Pages Cover1-
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
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Article type: Index
1993 Volume 49 Issue 1 Pages Toc1-
Published: January 01, 1993
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Article type: Index
1993 Volume 49 Issue 1 Pages Toc2-
Published: January 01, 1993
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[in Japanese]Article type: Article
1993 Volume 49 Issue 1 Pages i-ii
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages iii-xiii
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages xiv-xxi
Published: January 01, 1993
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KIKUO KOWADA, YASUSHI SUGANUMA, YASUSHI MATSUKI, TETSUROU UMEZAWA, TAK ...Article type: Article
1993 Volume 49 Issue 1 Pages 1-7
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSWe developed an original automatic exposure device in an effort to obtain better inspired chest radiograms in infants. The device employs a personal computer system to analyze changes in intra-mask pressure signals from a small mask which is placed on the patient's face, and calculates the satisfactory inspired intra-mask pressure before each exposure. Next, the device automatically releases X-rays when the intra-mask pressure reaches the appropriate level. Successful exposure rates of inspiratory radiography thus obtained were compared with those obtained manually by skilled technicians in 350 infantile chest radiograms; our automatic method showed a success rate of almost 100%, and had a statistically higher success rate than the manual method in younger infants. Other methods of automatic exposure were developed about 20 years ago; compared with these previously reported method, our computer-aided method has the advantage of being able to judge not only the phase of respiration but also the depth of respiration. From this study, we concluded that our automatic exposure device is very useful in making exact diagnosis and for comparative follow-up radiograms.View full abstractDownload PDF (1104K) -
TSUTOM NAKANOArticle type: Article
1993 Volume 49 Issue 1 Pages 8-11
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSA new measurement method of MR slice thickness is proposed. In this method, a high-contrast spatial resolution phantom, which is employed to evaluate the special resolution performance of MR equipment, is used. Slice thickness is obtained from the limit special frequency where the resolution pattern of the phantom vanishes on the image. New method is able to measure slice thickness accurately even a slice as thin as 2 or 3mm.View full abstractDownload PDF (477K) -
YOUJI TABATA, YASUFUMI OHGA, MITSUHIRO KAKUTA, SINJI NISIMURA, KANAME ...Article type: Article
1993 Volume 49 Issue 1 Pages 12-17
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSRecently, the measurability of visual evaluations has been attempted, but there is a possibility for the order of evaluation to be replaced by the difference of the observer's evaluation. Accordingly, it is necessary to know the confidence coefficient interval of rank. But it had stayed the significance test of equality by analysis of variance and T-test, the confidence coefficient of rank, when there is not the significance difference, couldn't be estimated. Therefore, by the application of T-test and dealing with the error rationally, the confidence coefficient among each scale becomes equally quantitative. As a result, it makes it possible to handle the scale flexibly.View full abstractDownload PDF (448K) -
AKIKO HATTORI, YOSHIYUKI UMEZU, HIROMI SAKAMOTOArticle type: Article
1993 Volume 49 Issue 1 Pages 18-23
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSCurrently the cassette system is a mainstream in mammography while the vacuum-packed system has been employed in our hospital. Nonetheless the vacuum-packed system is now facing the difficulty in dealing with the increasing demand of mammography because of its complexity and inconveniency. For above reasons this system was considered to be replaced by a cassette system. In this report, a cassette system was investigated to observe whether it can maintain as the same level of image quality as of vacuumpacked system. The test results found that a vacuum-packed system was superior in visual evaluation to a cassette system. One of the main reasons of its superiority is considered due to its less scattering X-Rays than that of a cassette system.View full abstractDownload PDF (572K) -
SHINYA ITO, KOUICHI FUJINO, YASUMITU KAWAGOE, MITSUHIRO MATSUMOTO, KUN ...Article type: Article
1993 Volume 49 Issue 1 Pages 24-31
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSOsaka University Hospital introduced a high dose rate remote after-loading system-micro-Selectron HDR-in April 1991 for the first time in Japan. This report discuses and evaluates the system : 1) Structure and function of the micro-Selectron HDR System. 2) Output measurement and position check of iridium source. 3) Application examples and therapy planning. Data of radiation source is important for dose calculation in brachytherapy; so, we here discuss the measurement method and result. We achieved an accuracy of ± 1mm for loaded source position. We believe that in an output measurement of an iridium source, it is possible to maintain reproducibility with an accuracy of within ± 1% when the exclusive output measuring instrument is used. We have applied this system to about 40 cases. As for therapy planning, we used an X-ray simulator and therapy planning computer. Then, we found that, even with complicated source arrangement, we could obtain dose distribution suitable to such case. Using the function of this system and our originality, we realized to expand application of brachytherapy.View full abstractDownload PDF (1113K) -
FUJIO ARAKI, KOZO KUMAGAIArticle type: Article
1993 Volume 49 Issue 1 Pages 32-38
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSIn radiation therapy of thorax region, it is necessary to apply absorbed dose correction for heterogeneity tissuse of lungs. Practically, however, it is not easy to do an accurate absorbed dose correction. We made a basic experiment for absorbed dose correction of heterogeneity tissue of lungs using thorax phantom for 10 MV X-rays, and evaluated the accuracy of depth dose calculation algorithms for its tissue which are available in conventional, commercial-based treatment-planning systems. Depth dose on the central axis in lung for small field of 5×5(cm)^2 was reduced by about 10% due to loss of lateral electronic equilibrium. Dose correction factor of heterogeneity was insensitive to the thickness of the build-up layer of this phantom if there was a longitudinal electronic equilibrium. The equivalent TAR (tissue-air ratio) method gave the greatest accuracy for dose calculation algorithms, of lungs whose error was within about 3% compared to the measured values. However, for the smaller field of 5×5(cm)^2, all our methods did not consider the effects of electron scattering, so that the equivalent TAR method and the ratio of TAR method gave errors of about 15% and the power law TAR method about 6%.View full abstractDownload PDF (608K) -
EIJI ANDO, FUMIAKI UTO, YUKITOSHI KOTOH, MASAKI MATSUOArticle type: Article
1993 Volume 49 Issue 1 Pages 39-42
Published: January 01, 1993
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[in Japanese], [in Japanese]Article type: Article
1993 Volume 49 Issue 1 Pages 43-57
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
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TOMOHIKO OKAWA, HISAE HIRABAYASHI, MIDORI KITA, MAKIKO TANAKAArticle type: Article
1993 Volume 49 Issue 1 Pages 58-61
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSTo improve the quality of radiotherapy and get brilliant results in cancer treatment, establishment of a quality system consisting of quality assurance and quality control is most important. The radiation prescription should be based on all available clinical information on Biology, natural history and imaging, and histology of the tumor. Treatment planning consists mainly of choice of the the best arrangement of a radiation treatment field (target volume) and localization of organs at risk to get the high precision method. Radiotherapy is an area where there is an urgent for more quality assurance, quality control and cooperative efforts at the national level.View full abstractDownload PDF (363K) -
MASAO HOSHINAArticle type: Article
1993 Volume 49 Issue 1 Pages 62-70
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSTo reproduce and keep the position of field alignment decided during treatment planning, it is necessary to immobilize and position the patients with exactness. Until now portal films have been used to verify and control the accuracy of fields alignment. For the study of deviation of field alignment, this article reviews the data published over the 10 or so years, and analyzes the extent of displacement from an intended position. From this analysis, it was shown that the extent of systematic and random errors had been at the same level. Therefore, it is effective in excluding systematic errors during the first session of radiotherapy, and then, it is expected to improve the uncertainty during the localization of fields. When a biteblock and plastic cast are used during patient setup, the extent of errors obviously decreased. Recently, electronic portal imaging devices are becoming available for radiotherapy. In this paper, advantage of these was discussed regarding use for patients setup. It is also important to improve the environment of radiotherapy (units and staff) as well as quality control. In Japan, especially, there are many problems with respect to radiotherapy staff. It is of urgent necessity in solving this problem.View full abstractDownload PDF (930K) -
YOSHIHARU WATANABEArticle type: Article
1993 Volume 49 Issue 1 Pages 71-76
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
JOURNAL FREE ACCESSQuality assurance of radiation treatment concerns not only accuracy in every step of treatment but also in all the systems. Therefore, we need a synthetic examination of quality assurance at each step of the treatment process, quality control of all external equipment and reproduction of treatment. The objective of radiation treatment planning is to simulate the method for delivering maximam dose to the target volume while keeping the dose to the target volume while keeping the dose given the target only of to the neighboring normal tissues as low as possible. For the sake of better simulation, we need three-dimension at treatment planning that has detailed three-possible dimensional anatomic information. It follows from what has been said that we need several image modalities for a clear understanding of the relationships between target volume and the organs. From now, we should establish a numerical scoring technique for the evaluating of treatment planning. Also, regarding the basis of the fact above, we need to analyze the evaluation numerically.View full abstractDownload PDF (665K) -
[in Japanese]Article type: Article
1993 Volume 49 Issue 1 Pages 77-79
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
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[in Japanese]Article type: Article
1993 Volume 49 Issue 1 Pages 80-91
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages 92-102
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages 103-106
Published: January 01, 1993
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[in Japanese]Article type: Article
1993 Volume 49 Issue 1 Pages 107-116
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages 117-119
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages 119-
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages App1-
Published: January 01, 1993
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Article type: Appendix
1993 Volume 49 Issue 1 Pages App2-
Published: January 01, 1993
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Article type: Cover
1993 Volume 49 Issue 1 Pages Cover2-
Published: January 01, 1993
Released on J-STAGE: June 29, 2017
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