Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
Search
Advanced search
OR
Browse
Search
Volume 64, Issue 9
Displaying 1-9 of 9 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
Opening Article
Program of the 36th Autumn Scientific Congress
Original
  • Risk-benefit Analysis of 18FDG PET Cancer Screening
    Takeshi Murano, Takeshi Iinuma, Yukio Tateno, Hiromitsu Daisaki, Ukihi ...
    2008 Volume 64 Issue 9 Pages 1151-1156
    Published: September 20, 2008
    Released on J-STAGE: October 08, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.1151
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The benefits of 18F-fluorodeoxyglucose (18FDG) positron emission tomography (PET) cancer screening are expected to include a large population of examinees and are intended for a healthy group. Therefore, we attempted to determine the benefit/risk ratio, estimated risk of radiation exposure, and benefit of cancer detection. We used software that embodied the method of the International Commission on Radiological Protection (ICRP) to calculate the average duration of life of radiation exposure. We calculated the lifesaving person years of benefit to be obtained by 18FDG PET cancer screening detection. We also calculated the benefit/risk ratio using life-shortening and lifesaving person years. According to age, the benefit/risk ratio was more than 1 at 35–39 years old for males and 30–34 years old for females. 18FDG PET cancer screening also is effective for examinees older than this. A risk-benefit analysis of 18FDG-PET/computed tomography (CT) cancer screening will be necessary in the future.
    View full abstract
    Download PDF (545K)
  • Trail of Artifact Reduction in Body Diffusion Weighted Imaging Development and Basic Examination of “TRacking Only Navigator”(TRON method)
    Tomohiko Horie, Tarou Takahara, Tetsuo Ogino, Tomoyuki Okuaki, Masatos ...
    2008 Volume 64 Issue 9 Pages 1157-1166
    Published: September 20, 2008
    Released on J-STAGE: October 08, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.1157
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    In recent years, the utility of body diffusion weighted imaging as represented by diffusion weighted whole body imaging with background body signal suppression (DWIBS), the DWIBS method, is very high. However, there was a problem in the DWIBS method involving the artifact corresponding to the distance of the diaphragm. To provide a solution, the respiratory trigger (RT) method and the navigator echo method were used together. A problem was that scan time extended to the compensation and did not predict the extension rate, although both artifacts were reduced. If we used only navigator real time slice tracking (NRST) from the findings obtained by the DWIBS method, we presumed the artifacts would be ameliorable without the extension of scan time. Thus, the TRacking Only Navigator (TRON) method was developed, and a basic examination was carried out for the liver. An important feature of the TRON method is the lack of the navigator gating window (NGW) and addition of the method of linear interpolation prior to NRST. The method required the passing speed and the distance from the volunteer’s diaphragm. The estimated error from the 2D-selective RF pulse (2DSRP) of the TRON method to slice excitation was calculated. The condition of 2D SRP, which did not influence the accuracy of NRST, was required by the movement phantom. The volunteer was scanned, and the evaluation and actual scan time of the image quality were compared with the RT and DWIBS methods. Diaphragm displacement speed and the quantity of displacement were determined in the head and foot directions, and the result was 9 mm/sec, and 15 mm. The estimated error was within 2.5 mm in b-factor 1000 sec/mm2. The FA of 2DSRP was 15 degrees, and the navigator echo length was 120 mm, which was excellent. In the TRON method, the accuracy of NRST was steady because of line interpolation. The TRON method obtained image quality equal to that of the RT method with the b-factor in the volunteer scanning at short actual scan time. The TRON method can obtain image quality equal to that of the RT method in body diffusion weighted imaging within a short time. Moreover, because scan time during planning becomes actual scan time, inspection can be efficiently executed.
    View full abstract
    Download PDF (1557K)
Data
  • Evaluation Factors for CR System Introduction Using AHP and Simulation
    Yuki Yokooka, Katsuhiko Ogasawara
    2008 Volume 64 Issue 9 Pages 1167-1171
    Published: September 20, 2008
    Released on J-STAGE: October 08, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.1167
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Medical institutions usually find it difficult to select computed radiography (CR) equipment because of the involvement of many complicated factors such as operability, processing time, and price. The analytic hierarchy process (AHP) is often applied in complex decision and evaluation situations. This study quantitatively evaluates the institution’s selection criteria of equipment using AHP. The AHP model of this study consisted of 3 levels: the goal, 6 evaluations, and 3 alternatives. Processing time, price operability, picture quality, connectivity, and equipment size were considered as the criteria for decision marking. We simulated alteration of priority of evaluations by changing the weight of pricing between 0 and 1. Results showed that price and connectivity accounted for 60% of the total weight. On excluding operability, the difference in weight between equipment was 1.16 times; the priority of processing time was 1.36 times; and the priority of price was 1.37 times. In the same way, when considering operability, the difference in weight between equipment was 0.36 times, the priority of processing time was 0.45 times, and the priority of price was 0.11 times.
    View full abstract
    Download PDF (538K)
Work in Progress
  • A New Method of Measuring Temporal Resolution for Computed Tomography
    Katsuhiro Ichikawa, Tadanori Takada, Takanori Hara, Kazuya Ohashi, Shi ...
    2008 Volume 64 Issue 9 Pages 1172-1176
    Published: September 20, 2008
    Released on J-STAGE: October 08, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.1172
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    In this study, we proposed a new method of measuring temporal resolution using an impulse signal in the time domain in computed tomography (CT). We employed a metal ball with a diameter of 11 mm as the source of the impulse signal, which was shot to a slice plane at a very fast speed during scanning, along the perpendicular direction to the plane. A 4-slice multi detector-row CT (MDCT) system was employed to evaluate the new method, and images for region of interest (ROI) measurement were reconstructed with a z-increment corresponding to a very short time (≤ 0.03 sec). Temporal sensitivity profiles (TSPs) for various helical beam-pitches were obtained by plotting averaged CT values within the ROIs against the temporal axis. The accuracy of the method was examined by comparing the measured TSPs with theoretical TSPs corresponding to respective helical beam-pitches. As a result, the theoretical TSPs and measured TSPs demonstrated high coincidence in all beam-pitches. Since the TSPs indicated the profiles with sharp shapes faithful to the theoretical TSPs, it was proved that the new method had sufficient inherent temporal resolution. It was indicated that the new method we proposed would be an effective method for evaluating temporal resolution in CT.
    View full abstract
    Download PDF (602K)
  • Development of an Automated 3D Segmentation Program for Volume Quantification of Body Fat Distribution Using CT
    Shunsuke Ohshima, Shuji Yamamoto, Taiki Yamaji, Masahiro Suzuki, Michi ...
    2008 Volume 64 Issue 9 Pages 1177-1181
    Published: September 20, 2008
    Released on J-STAGE: October 08, 2008
    DOIhttps://doi.org/10.6009/jjrt.64.1177
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The objective of this study was to develop a computing tool for full-automatic segmentation of body fat distributions on volumetric CT images. We developed an algorithm to automatically identify the body perimeter and the inner contour that separates visceral fat from subcutaneous fat. Diaphragmatic surfaces can be extracted by model-based segmentation to match the bottom surface of the lung in CT images for determination of the upper limitation of the abdomen. The functions for quantitative evaluation of abdominal obesity or obesity-related metabolic syndrome were implemented with a prototype three-dimentional (3D) image processing workstation. The volumetric ratios of visceral fat to total fat and visceral fat to subcutaneous fat for each subject can be calculated. Additionally, color intensity mapping of subcutaneous areas and the visceral fat layer is quite obvious in understanding the risk of abdominal obesity with the 3D surface display. Preliminary results obtained have been useful in medical checkups and have contributed to improved efficiency in checking obesity throughout the whole range of the abdomen with 3D visualization and analysis.
    View full abstract
    Download PDF (902K)
Students’ Page
JIRA Topics
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top