Entity

Time filter

Source Type


Yabunaka K.,Katsuragi Hospital | Yabunaka K.,University of Tokyo | Nakagami G.,University of Tokyo | Sanada H.,University of Tokyo | And 7 more authors.
IFMBE Proceedings | Year: 2011

Purpose: Videofluoroscopy is generally considered a "gold standard" technique for diagnosing dysphagia; however this technique exposes subjects to radiation. Ultrasonography is applied widely in clinical practice because of low cost, safety of the technique, and absence of radiation exposure. The purpose of this study was to investigate the application of B+M-mode ultrasound imaging as a new approach to quantify activity patterns of the geniohyoid muscles during swallowing and to assess the effect of bolus volume in healthy subjects. Subject and Methods: 25 healthy volunteers (13 male, 12 female) completed three repetitions each of four swallowing conditions: 1-, 5-, 10-, and 20-ml water bolus swallows. Simultaneous B/M-mode images were captured at two regions along the lateral geniohyoid muscle wall. Frozen frames of the moving image were analyzed, and the moving distance of the geniohyoid muscle wall from the resting point was measured (X axis, time; Y axis, perpendicular to the range of motion). We measured moving distance of the geniohyoid muscle wall during contraction and duration of movement of the geniohyoid muscle. Results: In all cases, ultrasonographic images of the geniohyoid muscle movement during swallowing were easily visualized using the real-time B/M-mode. The average moving distance and the average duration of movement of the geniohyoid muscle during swallowing increased gradually by bolus volume increased. Mean moving distance was significantly increased at bolus volume of 20ml compared to 1ml, 5ml, and 10ml, and with 10ml compared to 1ml. Mean duration was significantly increased at bolus volume of 20ml compared to 1ml, 5ml, 10ml. Conclusion: B/M-mode ultrasound imaging provides a simple and noninvasive technique to visually assess the lateral geniohyoid muscle wall and may provide a clinical method for direct evaluation for swallowing. © 2011 Springer-Verlag Berlin Heidelberg.


Gotanda T.,Oishi Hospital | Gotanda T.,Himeji Dokkyo University | Katsuda T.,Seikeikai College | Akagawa T.,Red Cross | And 8 more authors.
Australasian Physical and Engineering Sciences in Medicine | Year: 2013

Recently developed radiochromic films can easily be used to measure absorbed doses because they do not need development processing and indicate a density change that depends on the absorbed dose. However, in GAFCHROMIC EBT2 dosimetry (GAF-EBT2) as a radiochromic film, the precision of the measurement was compromised, because of non-uniformity problems caused by image acquisition using a flat-bed scanner with a transmission mode. The purpose of this study was to improve the precision of the measurement using a flat-bed scanner with a reflection mode at the low absorbed dose dynamic range of GAF-EBT2. The calibration curves of the absorbed dose versus the film density for GAF-EBT2 were provided. X-rays were exposed in the range between ~0 and 120 mGy in increments of about 12 mGy. The results of the method using a flat-bed scanner with the transmission mode were compared with those of the method using the same scanner with the reflection mode. The results should that the determination coefficients (r 2 ) for the straight-line approximation of the calibration curve using the reflection mode were higher than 0.99, and the gradient using the reflection mode was about twice that of the one using the transmission mode. The non-uniformity error that is produced by a flat-bed scanner with the transmission mode setting could be almost eliminated by converting from the transmission mode to the reflection mode. In light of these findings, the method using a flat-bed scanner with the reflection mode (only using uniform white paper) improved the precision of the measurement for the low absorbed dose range. © 2013 Australasian College of Physical Scientists and Engineers in Medicine.


Gotanda T.,Oishi Hospital | Gotanda T.,Himeji Dokkyo University | Katsuda T.,Seikeikai College | Gotanda R.,Ibaraki Prefectural University of Health Sciences | And 9 more authors.
IFMBE Proceedings | Year: 2011

Although the half-value layer (HVL) is one of the important parameters for quality assurance (QA) and quality control (QC), constant monitoring has not been performed because measurements using an ionization chamber (IC) are time-consuming. To solve these problems, a method using radiochromic film and step-shaped aluminum (Al) filters has been developed. In this study, GAFCHROMIC EBT2 dosimetry film (GAF-EBT2) and GAFCHROMIC XR TYPE-R dosimetry film (GAF-R) has been used. The measurement X-ray tube voltage was 120 kV. Two radiochromic films were scanned using a flat-bed scanner. To remove the nonuniformity error of scanned images, image J version 1.40g image analysis software has been used. HVL was evaluated using the density attenuation ratio. The HVLs and second HVLs of GAF-EBT2, GAF-R, and an IC dosimeter were compared. The HVLs (second HVLs) at 120 kV using GAF-EBT2, GAF-R, and an IC dosimeter were 4.47 mm (10.97 mm), 4.17 mm (8.61 mm), and 4.03 mm (10.35 mm) respectively, and the effective energies were 40.6 keV, 39.3 keV, and 38.7 keV, respectively. The difference ratios of the second HVLs using GAF-EBT2 (GAF-R) and an IC dosimeter were 6.0% (- 16.8%), -10.6% (-11.6%), and 5.1% (-0.2%), respectively. In addition, the difference ratio of the second HVLs at 120 kV using GAF-EBT2 and GAF-R was 27.4%. GAF-EBT2 and GAF-R proved to be capable of measuring effective energy within an error range of less than 5%. However, in HVL measurements of devices operating in the high-energy range (X-ray CT, radiotherapy machines, and so on), GAF-EBT2 was found to offer higher measurement precision than GAF-R, because it shows only a slight energy dependency. © 2011 Springer-Verlag Berlin Heidelberg.


Yamamoto K.,Osaka Cancer Prevention and Detection Center | Yamamoto K.,Osaka University | Takeda Y.,Okayama University | Katsuda T.,Seikeikai 2 Gakuin | And 9 more authors.
IFMBE Proceedings | Year: 2011

High-density barium sulfate (HDB) has been recommended by the Japanese Society of Gastroenterological Cancer Screening (JSGCS) and used in many medical facilities. However, it is not confirmed that the new method using HDB is superior in diagnostic validity compared to the conventional method using moderate-density barium sulfate (MDB). Pre viously, the authors reported that both methods showed simi lar validity in terms of sensitivity and specificity in gastric cancer screening. In this study, sensitivity and specificity were re-examined in more detail by area under receiver-operating characteristic (ROC) curves (AUC) analysis, especially on the sex (male, female) and the ages (≥50, <50, ≥55, <55, ≥60, <60) of subjects. The results showed that the diagnostic validity of the method using HDB is almost same to that of the conven tional method using MDB. Clinical improvement in gastric cancer screening is in need of further studies on the new me thod using HDB. © 2011 Springer-Verlag Berlin Heidelberg.


Yatake H.,Breast Cancer Center | Yatake H.,Okayama University | Sawai Y.,Breast Cancer Center | Kobayashi N.,Breast Cancer Center | And 11 more authors.
IFMBE Proceedings | Year: 2011

It has been reported that if the physician suspects cancer during standard mammography (craniocaudal and mediolateral oblique views), undertaking additional mammography under the physician's order improves the diagnostic accuracy of breast cancer. The aim of our study was to determine whether additional mammography, as judged necessary by the radiographer, improves the diagnostic accuracy of breast cancer during mammography. Our Institutional Review Board approved the study. Mammography was performed at a single hospital in Osaka, Japan between June 2009 and March 2010. A total of 2636 individuals underwent mammography as workup. Of the 101 cases of cancer finally diagnosed, we examined a total of 75 cases were additional mammography had been undertaken. Three physicians certified as film readers by the Central Committee on Quality Control of Mammographic Screening in Japan, reinterpreted mammograms. The first reinterpretation involved only standard mammograms and the second included both standard and additional mammograms. Films were categorized by consensus on a five-point scale defining the degree to which cancer was suspected. To determine a category difference between standard mammograms alone, and both standard and additional mammograms, we used the Wilcoxon signed ranks test. A P value of <0.05 was considered significant. We evaluated the 75 cancer cases and found that the categories of cancer cases reinterpreted with standard and additional mammography was significantly higher (P <0.001) than the categories of cancer cases reinterpreted with standard mammography alone. In addition, we reinterpreted 43 cancer cases in which a lesion was not identified by the physician at the time that the mammography was ordered, and found that the categories of cancer cases reinterpreted with standard and additional mammography was significantly higher than the categories of cancer cases reinterpreted reinterpreted with standard mammography alone (P = 0.012). Undertaking additional mammography, as judged necessary by the radiographer, improved breast cancer diagnostic accuracy. © 2011 Springer-Verlag Berlin Heidelberg.

Discover hidden collaborations