Japanese Journal of Radiological Technology
Online ISSN : 1881-4883
Print ISSN : 0369-4305
ISSN-L : 0369-4305
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Volume 68, Issue 4
Displaying 1-17 of 17 articles from this issue
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Opening Article
Originals
  • Clinical Study to Obtain True View of the Glenohumeral Joint on Scapula-45
    Hironobu Fujisawa, Kyoichi Kato, Hiroki Nishimura, Naoya Nishinaka, Ke ...
    2012 Volume 68 Issue 4 Pages 397-403
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.397
    JOURNAL FREE ACCESS
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    Scapula-45 is an original roentogenographical technique to clarify objectively the function of the rotator cuff and scapulothoracic joint. This examination enables assessment of the function of the rotator cuff and scapulothoracic joint utilizing the radiographs of the glenohumeral joint. However, in the former technique, it was difficult for the technician to properly align the patient for the view of the true glenohumeral joint because of the individual postural difference of the patients, such as kyphosis. In the present study, we reported a new technique with the use of the acromion, coracoid process, and inferior angle of the scapula as a landmark to obtain the consistent radiographs of the glenohumeral joint.
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  • Image Quality Evaluation of New Image Reconstruction Methods Applying the Iterative Reconstruction
    Tadanori Takata, Katsuhiro Ichikawa, Hiroyuki Hayashi, Wataru Mitsui, ...
    2012 Volume 68 Issue 4 Pages 404-412
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.404
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    The purpose of this study was to evaluate the image quality of an iterative reconstruction method, the iterative reconstruction in image space (IRIS), which was implemented in a 128-slices multi-detector computed tomography system (MDCT), Siemens Somatom Definition Flash (Definition). We evaluated image noise by standard deviation (SD) as many researchers did before, and in addition, we measured modulation transfer function (MTF), noise power spectrum (NPS), and perceptual low-contrast detectability using a water phantom including a low-contrast object with a 10 Hounsfield unit (HU) contrast, to evaluate whether the noise reduction of IRIS was effective. The SD and NPS were measured from the images of a water phantom. The MTF was measured from images of a thin metal wire and a bar pattern phantom with the bar contrast of 125 HU. The NPS of IRIS was lower than that of filtered back projection (FBP) at middle and high frequency regions. The SD values were reduced by 21%. The MTF of IRIS and FBP measured by the wire phantom coincided precisely. However, for the bar pattern phantom, the MTF values of IRIS at 0.625 and 0.833 cycle/mm were lower than those of FBP. Despite the reduction of the SD and the NPS, the low-contrast detectability study indicated no significant difference between IRIS and FBP. From these results, it was demonstrated that IRIS had the noise reduction performance with exact preservation for high contrast resolution and slight degradation of middle contrast resolution, and could slightly improve the low contrast detectability but with no significance.
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  • MRI Image Reconstruction Using Polar-coordinates Conversion of k-space Data
    Atsushi Tachibana, Takeyuki Hashimoto, Kazuya Sakaguchi, Takayuki Obat ...
    2012 Volume 68 Issue 4 Pages 413-421
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.413
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    In this study, we proposed the new reconstruction techniques for magnetic resonance imaging (MRI) using filtered back projection (FBP) or simultaneous reconstruction technique (SIRT). We converted the k-space which was acquired by conventional phase-encoding schemes from Cartesian coordinates to polar coordinates and created the projection. The linear interpolation and the sinc interpolation were used in the conversion. The accuracy of the reconstructed image using projection was evaluated by the relative error in comparison with the standard image which was reconstructed by the two-dimensional Fourier transform (2DFT) with conventional Cartesian k-space. The relative error reconstructed both FBP and SIRT from projection with sinc interpolation is 0.013. The maximum value of standard image is 1.501451, FBP is 1.47921, and SIRT with iteration 100 is 1.44858 and with iteration 200 is 1.579442. The minimum value of both the standard image and the others is about 0. Visually, there is no margin between the standard image and the reconstructed image from projection with FBP or SIRT.
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  • Development of Image Quality Assurance Support System Using Image Recognition Technology in Radiography in Lacked Images of Chest and Abdomen
    Toru Shibuya, Kyouichi Kato, Hidekazu Eshima, Shinichirou Sumi, Tadash ...
    2012 Volume 68 Issue 4 Pages 422-431
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.422
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    In order to provide a precise radiography for diagnosis, it is required that we avoid radiography with defects by having enough evaluation. Conventionally, evaluation was performed only by observation of a radiological technologist (RT). The evaluation support system was developed for providing a high quality assurance without depending on RT observation only. The evaluation support system, called as the Image Quality Assurance Support System (IQASS), is characterized in that “image recognition technology” for the purpose of diagnostic radiography of chest and abdomen areas. The technique of the system used in this study. Of the 259 samples of posterior-anterior (AP) chest, lateral chest, and upright abdominal x-rays, the sensitivity and specificity was 93.1% and 91.8% in the chest AP, 93.3% and 93.6% in the chest lateral, and 95.0% and 93.8% in the upright abdominal x-rays. In the light of these results, it is suggested that AIQAS could be applied to practical usage for the RT.
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  • Physics Properties of Non-helical Scan Using 320-row Multi Detector Computed Tomography
    Atsushi Urikura, Yoshihiro Nakaya, Katsuhiro Ichikawa, Keisuke Kawatan ...
    2012 Volume 68 Issue 4 Pages 432-442
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.432
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    Recently, clinical applications utilizing 320-row multi detector computed tomography (320MDCT) have increased, and the physical image properties of 320MDCT have been more concerned. We evaluated the spatial resolution in scan plane and z-direction, image noise and low-contrast sensitivity of non-helical mode (320NH), 640 slices mode by a double slice reconstruction technology (640DS), and 64-row helical mode (64HE) by using a 320MDCT. The spatial resolution in z-direction was evaluated by the section sensitivity profile (SSP) measurement with the micro coin phantom and the contrast transfer ratio (CTR) with the 0.5-mm comb phantom. The in-plane spatial resolution of 320NH was uniform over all the slice positions. The spatial resolution in z-direction decreased from the cathode side toward the anode side. The image noise of the anode side was higher than that of the cathode side. The contrast to noise ratio as index of the low contrast sensitivity was uniform over all the slice position. The CTR of 320NH fluctuated in the z-position, and the fluctuation was improved by 640DS except for the center of rotation.
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Notes
  • Comparison of Dose Accuracy between 2D Array Detectors for Pre-treatment IMRT QA
    Yuji Nakaguchi, Fujio Araki, Shunji Saiga, Tomohiro Kouno, Masato Maru ...
    2012 Volume 68 Issue 4 Pages 443-452
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.443
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    The dosimetric properties between various 2D array detectors were compared and were evaluated with regard to the accuracy in absolute dose and dose distributions for clinical treatment fields. We used to check the dose accuracy: 2D array detectors; MapCHECK (Sun Nuclear), EPID (Varian Medical Systems), EPID-based dosimetry (EPIDose, Sun Nuclear), COMPASS (IBA) and conventional system; EDR2 film (Eastman Kodak), Exradin A-14SL ion chamber (0.016 cc, Standard Imaging). First, we compared the dose linearity, dose rate dependence, and output factor between the 2D array detectors. Next, the accuracy of the absolute dose and dose distributions were evaluated for clinical fields. All detector responses for the dose linear were in agreement within 1%, and the dose rate dependence and output factor agreed within a standard deviation of ±1.2%, except for EPID. This is because EPID is fluence distributions. In all the 2D array detectors, the point dose agreed within 5% with treatment planning system (TPS). Pass rates of each detector for TPS were more than 97% in the gamma analysis (3 mm/3%). EPIDose was in a good agreement with TPS. All 2D array detectors used in this study showed almost the same accuracy for clinical fields. EPIDose has better resolution than other 2D array detectors and thus this is expected for dose distributions with a small field.
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  • A Design of Two-Dimensional Time-of-Flight Using the Multi Echo Collection
    Hiroki Nakajima, Tsuyoshi Ueyama
    2012 Volume 68 Issue 4 Pages 453-460
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.453
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    In general, gradient echo (GRE) is used for the echo acquisition of two-dimensional time-of-flight (2D-TOF). It takes time to the image acquisition by 2D-TOF. Then, we designed the use of GRE-echo planar imaging (EPI) to the echo collections of 2D-TOF. We compared two pulse sequences using the following: contrast, signal to noise ratio, the distortions, and magnetic resonance angiography (MRA) images. The signal intensity ratio between blood vessel and fat was superior to the GRE-EPI. Signal to noise ratio of GRE-EPI was inferior to GRE. When the number of collection echoes of GRE-EPI is carried out by four, there was no distortion. The contrast of the blood vessel has improved when GRE-EPI was used. Image acquisition time improved to about 23 percent earlier. The blood vessel of the parent trunk was able to be described in the image of the lower limbs blood vessel. However, the description of the peripheral vessel was dominant 2D-TOF that used GRE. In clinical, the description of the peripheral vessel may not be important. With such a case, this method is effective. Moreover, shortening the image acquisition time brings a reduction to the load of the patient.
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Clinical Technology
  • Usefulness of Imaging Posture Using Anterior View of the Half Supine Position for Sentinel Lymphscintigraphy in Patients with Breast Cancer
    Hironori Ichihara, Masahisa Onoguchi, Kazuhisa Hiyoshi, Tomoko Saitou, ...
    2012 Volume 68 Issue 4 Pages 461-467
    Published: April 20, 2012
    Released on J-STAGE: April 20, 2012
    DOIhttps://doi.org/10.6009/jjrt.2012_JSRT_68.4.461
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    Objectives: Sentinel lymphoscintigraphy(SLSG) is focused on the visualization of an injection site and lymph nodes. Therefore, an anterior view is effective in identifying the location of a lymph node easily. For this reason, we devised a new imaging method of anterior view (Modified Anterior View; MAV), and the usefulness was assessed. Methods: SLSG was obtained in 166 patients with breast cancer. In MAV imaging, patients were laid in an oblique position on a triangular styrene foam elevating the target axillary side. The detector was also leaned. Just after the MAV were imaged, the patient was shifted to the supine position and the SAV imaging was also performed using the same acquisition times. Results: The detectability of MAV and SAV was 92.42% and 81.99%, respectively. However, the detectability of SAV showed the better value for the few cases which the lymph node detected by the inside of injection site. Conclusion: MAV may improve detectability of SLN. However, SAV is still required for a few cases in which lymph node is detected by the inside of injection site.
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Data
The 39th Autumn Scientific Congress
Series—From Diagnosis of the Breast to Treatment
Clinical Technology Course
Virtual Inteview for Graduate School and Laboratories
JIRA Topics
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