Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
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Volume 65, Issue 8
Displaying 1-20 of 20 articles from this issue
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Opening Article
Originals
  • Developing and Evaluating an Auto-retrieval Algorithm for Abbreviations in Academic Articles
    Michika Wakoh, Naoki Nishimoto, Masahito Uesugi, Takayoshi Terashita, ...
    2009 Volume 65 Issue 8 Pages 1025-1031
    Published: August 20, 2009
    Released on J-STAGE: September 01, 2009
    DOIhttps://doi.org/10.6009/jjrt.65.1025
    JOURNAL FREE ACCESS
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    The purpose of this study was to develop an automated acquisition support for the semantics of abbreviations and evaluate its performance with respect to academic articles. Our goal was to support the maintenance of an institution-specific semantics inventory for abbreviations on a continuous basis. We retrieved articles from MEDLINE with the keyword “Liver [MeSH],” and 100 abstracts were randomly selected. Abbreviations and their full forms were retrieved using original Java software based on the following rules. (1) Searching the parentheses in the abstracts, the words inside the parentheses were retrieved as “INNER” and the words in front of the parentheses were retrieved as “OUTER.” (2) Matching rules, such as whether the first characters of INNER and OUTER were the same. (3) If the words satisfied the conditions stated at (2), INNER was saved as the abbreviation and OUTER as the full form. Performance was manually evaluated by two graduate students and a radiologist. Of the 165 pairs of abbreviations and full forms that were obtained, 145 (87.9%) constituted correct matches.
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  • Development of Test Bolus Tracking Method and Usefulness in Coronary CT Angiography
    Takayoshi Yamaguchi, Daichi Takahashi
    2009 Volume 65 Issue 8 Pages 1032-1040
    Published: August 20, 2009
    Released on J-STAGE: September 01, 2009
    DOIhttps://doi.org/10.6009/jjrt.65.1032
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    The test bolus tracking (TBT) method is a new injection method of contrast medium that we developed. The TBT method is an injection technique that continuously performs the test bolus injection and the main bolus injection, such that the best acquisition of scan timing and the improvement of examination efficiency can be expected. We compared the TBT method and the test injection method by coronary CT angiography. The results demonstrated that the contrast enhancement of the coronary arteries was high and the variation of the CT value was also small in the TBT method. When the scan timing expected by the TI method and the TBT method were compared, it was different of two seconds or more by the case with 43%. However, the variation of CT value was small for the TBT method in these cases. Therefore, the TBT method is a very useful method for CCTA.
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Notes
  • Examination of Accuracy and Factors Influencing Optical Coherence Tomography(OCT)Measurements
    Noriyuki Negi, Masanobu Koto, Junya Shite, Takahiro Sawada, Hideaki Ka ...
    2009 Volume 65 Issue 8 Pages 1041-1047
    Published: August 20, 2009
    Released on J-STAGE: September 01, 2009
    DOIhttps://doi.org/10.6009/jjrt.65.1041
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    Introduction: Optical coherence tomography (OCT) is a new imaging modality with increasing clinical application. In the present study, we examined the accuracy and factors influencing the OCT measurements (luminal diameter, area, and stent strut thickness).Methods: We evaluated several luminal sizes of phantom model by OCT with several situations (frame-rate: 8.2 or 15.6 F/s; pullback-speed: 1.0 or 2.0 mm/s; position of Image Wire: in-center; off-center) and compared them with the actual value and the intravascular ultrasound measurements. We also evaluated the accuracy of the stent strut thickness (5 bare metal stents and 2 drug eluting stents) in stents that were implanted to phantom models.Results: The accuracy of OCT measurements was affected by frame-rate and the position of OCT Image Wire. The distortion and the change in brightness of the OCT image were detected when the Image Wire was positioned off-center, especially at low frame-rate. In this condition, OCT measured the luminal diameter and area larger than the actual size. As for the strut thickness, when we unified the measurement points of the stent strut surface, the precision of the OCT measurements was satisfactory.Conclusion: We revealed that the precision of the OCT measurements was satisfactory. However, we should note that the OCT measurements were affected by frame-rate and position of the Image Wire.
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  • Evaluation of Exposure Dose for Panoramic Radiography
    Yoshihiko Hoshino, Yasuhiro Fukushima, Takayuki Sutou, Junya Fukuda, M ...
    2009 Volume 65 Issue 8 Pages 1048-1054
    Published: August 20, 2009
    Released on J-STAGE: September 01, 2009
    DOIhttps://doi.org/10.6009/jjrt.65.1048
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    Purpose: There is no established method to determine a diagnostic reference level of panoramic radiology. As the basic principle of the panoramic radiology dose index (PRDI) and CT dose index (CTDI) is almost identical, we evaluated the usefulness of PRDI for this purpose.Methods: Using the imaging plate (IP) sandwiched between the 160-mm thick acrylic disks, horizontal radiation dose distribution was analyzed by the conventional radiographic technique. Panoramic exposure dose was measured using the CT ionizing chamber that was placed at the tracking focus. Beam height was used as measurement unit, and PRDI was normalized and calculated.Results: There were two foci showing the maximum exposure dose for this panoramic equipment, located symmetrically 45 mm away from the center of the object. The PRDI of medium-sized individuals measured by this method was 0.74 mGy.Conclusion: We suggested a method to evaluate a diagnostic reference level, measuring the dose of exposure focus, i.e., maximum dose on panoramic radiology.
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Clinical Technology
  • Role of Weighted Maximum Intensity Projection with MDCT in the Diagnosis of Skull Fractures
    Tateya Fukunaga, Kiyomi Minakuchi, Kouji Yamamoto, Tomonori Maeda, Koz ...
    2009 Volume 65 Issue 8 Pages 1055-1063
    Published: August 20, 2009
    Released on J-STAGE: September 01, 2009
    DOIhttps://doi.org/10.6009/jjrt.65.1055
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    The method of image processing has increased along with the workstation in recent years and developments in the software of each modality. Maximum intensity projection (MIP) and volume rendering (VR) are among the general processing methods used. However, MIP and VR have their respective limitations. MIP does not have in-depth information, and in VR the final image depends on threshold processing. In comparison with MIP/VR, Weighted MIP can obtain in-depth information. The processing method is also easy and is used in the pre-operative simulation of neurosurgical craniotomy. In this study, we examined the effect of Weighted MIP on a phantom and in 7 cases of skull fracture by using multi-detector-row computed tomography. In the phantom study, Weighted MIP provided three-dimensional imaging in all the processing methods for skull fractures. Weighted MIP depicted the entire fracture line in a clinical study, and it was effective in all of the 7 skull fracture cases. In conclusion, the present study demonstrated that Weighted MIP with depth information was effective in the fracture line detection of skull fracture.
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  • Influence on Dose Calculation by Difference of Dose Calculation Algorithms in Stereotactic Lung Irradiation: Comparison of Pencil Beam Convolution (inhomogeneity correction: Batho Power Law) and Analytical Anisotropic Algorithm
    Masayuki Tachibana, Yoshitaka Noguchi, Jyunichi Fukunaga, Naomi Hirano ...
    2009 Volume 65 Issue 8 Pages 1064-1072
    Published: August 20, 2009
    Released on J-STAGE: September 01, 2009
    DOIhttps://doi.org/10.6009/jjrt.65.1064
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    The monitor unit (MU) was calculated by pencil beam convolution (inhomogeneity correction algorithm: batho power law) [PBC (BPL)] which is the dose calculation algorithm based on measurement in the past in the stereotactic lung irradiation study. The recalculation was done by analytical anisotropic algorithm (AAA), which is the dose calculation algorithm based on theory data. The MU calculated by PBC (BPL) and AAA was compared for each field. In the result of the comparison of 1031 fields in 136 cases, the MU calculated by PBC (BPL) was about 2% smaller than that calculated by AAA. This depends on whether one does the calculation concerning the extension of the second electrons. In particular, the difference in the MU is influenced by the X-ray energy. With the same X-ray energy, when the irradiation field size is small, the lung pass length is long, the lung pass length percentage is large, and the CT value of the lung is low, and the difference of MU is increased.
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  • Optimization of Contrast Injection Protocol for Coronary CTA: Adjustment of Injection Iodine Volume on Test Bolus Parameters and Patients’ Sex and BSA
    Nobuyuki Akiyama, Yukihiro Nakamura
    2009 Volume 65 Issue 8 Pages 1073-1080
    Published: August 20, 2009
    Released on J-STAGE: September 01, 2009
    DOIhttps://doi.org/10.6009/jjrt.65.1073
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    The purpose of this study was to correlate test bolus (TB) parameters and patient information and cardiac function with main bolus (MB) contrast density for 64-slice computed tomography, and to evaluate MB contrast density on a fixed injection rate, in comparison with an injection rate adjusted with TB parameters and patient information. A total of 256 patients underwent coronary CT angiography. In 126 patients (group 1), contrast material was administered at a flow rate of 4 ml/sec. The peak enhancement, the time needed to reach the peak of the TB and cardiac function of the MB were calculated for each patient in this group. The dependency of MB contrast attenuation on these parameters was evaluated. Significant correlations were obtained between the peak density of the TB and the patient’s body surface area (BSA) with the enhancement of MB. Furthermore, females showed a higher peak enhancement of MB than males. In view of the results of group 1, in the other 130 patients (group 2) injection protocols were computed by using regression analysis of each patient’s attenuation response to a TB and patient sex and BSA. Compared with group 1, the variations of MB contrast density of group 2 were reduced. Optimized contrast injection protocols are useful to reduce variations of MB contrast density, by taking these TB parameters and patient sex and BSA into account.
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Special Plan−Honorary Member Interview
The 35th Autumn Scientific Congress
Basic Lecture—Physical Image Quality Assessment in Digital Radiography
Clinical Technology Course
Science Exchanges Committee News
JIRA Topics
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