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Volume 17 (2000)
- Issue 3 Pages 113-
- Issue 2 Pages 55-
- Issue 1 Pages 7-
Volume 17, Issue 1
Displaying 1-5 of 5 articles from this issue
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Shozo SAWADA2000 Volume 17 Issue 1 Pages 7-13
Published: 2000
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSChrmosome aberrations in the lymphocytes of radiological technologists (RT) in Kumamoto Prefecture were analyzed by the trypsin G-banding method to estimate the exposure dose to radiation. Structural aberrations were identified in 384 (2.5%) of 15,442 cells analyzed from 53 RT as compared to 177 (1.6%) of 11,136 cells from 36 healthy controls. Stable aberrations were the most frequent in both groups and were either translocations or deletions. Unstable aberrations were mainly acentric fragments in both groups. The frequency of translocations and acentric fragments was significantly higher in the RT than in the controls and was highest in the RT over 50 years old. The highest frequency observed in the >50 age group was attributed to the unknown for cumulative dose prior to introduction of film badges. Dose estimation for each RT was done by using dose-response curves of stable and unstable type of chromesome aberrations. The relationship between frequency of chromesome aberrations and cumulativeradition doses of the 53 RT can be expressed by the equation y = 0.22 + 0.37D + 4.35D2, r = 0.702, where y is corrected frequency of chromosome aberrations after subtracting the increase with age and D is the cumulative radiation dose in Sv.View full abstractDownload PDF (1321K) -
Simulation of Wiener spectra of Symmetrical Screen-Film System and Verification using by MeasurementHiroharu OKADA, Komyo KARIYA2000 Volume 17 Issue 1 Pages 14-23
Published: 2000
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSWe simulated Wiener spectra for density range with a symmetric screen-film system applying Wakamatsu's mathematical model of Wiener spectrum by the two methods, and compared with the simulated Wiener spectra and the practical measured Wiener spectra. On one method, the Wiener spectra were simulated as base of the Wiener spectrum at the double density 1.0(Singled layer method). On the another method, the Wiener spectra were simulated as base of the two Wiener spectra at the front emulsion density 0.65 and the back emulsion density 0.52. The two simulated Wiener spectra were added in every relative exposure ( Doubled layer method). On the comparison with the simulated Wiener spectra and the measured Wiener spectra, the relative errors of Wiener spectra became lower the doubled layer method than the singled layer method. The relative errors on the doubled layer method were almost less than 15% at practical useful range. Therefore, to simulate the high precision of the Wiener spectra for density range with a symmetric screen-film system, we should individually simulate Wiener spectra on front and back emulsions. It is necessary to obtain a large number of sample points for determination of the Wiener spectrum, the accurate characteristic curve and gradient curve by the sensitometry.View full abstractDownload PDF (1951K) -
Seihaku HIGUCHI2000 Volume 17 Issue 1 Pages 24-28
Published: 2000
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSA large size of storage is required for the data obtained in the fields such as image diagnosis, physical measuring of phenomena and so on. In order to deduct this heavy burden, a reversible data compression is always employed for a perfect reconstruction. In this paper, a multi-valued image is transformedto the bit planes whose number is neccesary to exactly express the pixel value of original image. Above transformation process is carried out so as to increase the length of l's run on the bit plane. Based on the information whether the value at the position near the target bit to be compressed is 1or 0, conditional probability on target bit is adaptively changed. Arithmetic coding is carried out by utilizing above formulation. Simulation studies for Girl image(SIDBA) and X-ray image of crotch joint shows the effectiveness of proposed procedure.View full abstractDownload PDF (2392K) -
Shigehiro FUKUSHIMA, Kouichi MIYAZAKI, Kouichi YOSHIMOTO2000 Volume 17 Issue 1 Pages 29-39
Published: 2000
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSA method was developed for recognizing the barium-pool regions from a double-contrast gastric radiogram, as one module of image understanding for computer-aided diagnosis of the gastric cancer. The method is bottom-up. Firstly, pixels of low gray levels and of hollows are extracted as possiblebel ongings. Then, round regions are formed by grouping these pixels if they are cluttered. This operation eliminates small regions and linear regions at the same time. The barium-pools are coarsely extracted by testing gray level differences at the region boundaries. Finally, region growing is applied for fine extraction.View full abstractDownload PDF (12550K) -
New Approach to Masses with a Partial Loss of RegionYuji HATANAKA, Hiroshi FUJITA, Takeshi HARA, Shenglan LI, Tokiko ENDO2000 Volume 17 Issue 1 Pages 40-44
Published: 2000
Released on J-STAGE: August 27, 2012
JOURNAL FREE ACCESSA new method for detecting the masses with a partial loss has been developed for improving the detection sensitivity of our CAD scheme on mammograms. In this technique, the partial loss mass is identified by the similarity to the model with a sector form. In order to calculate the similarity, there are four features presented as (1) average of pixel values, (2) standard deviation of pixel values, (3) standard correlation coefficient defined by the sector model, and (4) concentration feature by density gradient. After applying the new method to 335 digitized mammograms, the detection sensitivity for the partial loss masses improved from 70% to 97% at the number of falsepositives changed from 1.0 to 1.2 per image. Such result indicated that the new technique is effective to improve the performance of our CAD system.View full abstractDownload PDF (4073K)
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