Gifu University of Medical Science

About: Gifu University of Medical Science is a education organization based out in Gifu City, Japan. It is known for research contribution in the topics: Imaging phantom & Motion sickness. The organization has 89 authors who have published 202 publications receiving 1350 citations.

Identification of breast tissue using the x-ray image measured with an energy-resolved cadmium telluride series detector based on photon-counting technique

Abstract: We have been developing a new mammography device with a cadmium-telluride series energy-resolved photon-counting X-ray detector. Using a photon-counting technique, we examined the sensitivity of the system for differentiating the composition of breast tissue and detecting breast tumors. To differentiate breast tissues, we prepared surgically resected specimens fixed in formalin, consisting of adipose, mammary-gland, and tumor tissues. In order to obtain the values of certain effective atomic numbers, we prepared phantoms with 0%, 50% and 100% simulated mammary-gland tissue. In our imaging system, the X-ray spectrum penetrating the object was measured using three energy bins, and the products of linear attenuation coefficients and thicknesses for the three bins were calculated. These linear attenuation coefficients were properly corrected for beam hardening and normalized, to ignore the thickness. These calculations were applied for each pixel, and the gravity point per ROI (region of interest) was plotted on scatterplots to examine their distribution. Adiposetissue values were similar to known values; however, mammary-gland values were distant from expected values. In most specimens, the tumor points were focused; however, in some specimens, it was difficult to distinguish between tumor and mammary-gland tissues given their close linear attenuation coefficients. Mammary-gland tissues may have been influenced by formalin, given its tubular structure.

[Dose Distribution Combinations of Different Electron Beam Energy for Treatment Region Expansion in High-energy Electron Beam Radiation Therapy: A Feasibility Study].

Abstract: INTRODUCTION External electron beams have excellent distributions in treatment for superficial tumors while suppressing influence deeper normal tissue. However, the skin surface cannot be given a sufficient dose due to the build-up effect. In this study, we have investigated the combination of electron beams to expand the treatment region by keeping the dose gradient beyond dmax. MATERIALS AND METHODS The percentage depth doses of different electron beams were superimposed on a spreadsheet to determine the combinations of electron beams so that the treatment range was maximized. Based on the obtained weight for electron beams, dose distributions were calculated using a treatment planning system and examined for potential clinical application. RESULTS With the combination of 4 MeV and 9 MeV electron beams, the 90% treatment range in the depth direction increased by 8.0 mm, and with 4 MeV and 12 MeV beams, it increased by 4.0 mm, with the same maximum dose depth and halfdose depth of the absorbed dose. The dose calculations were performed using the treatment planning system yielded similar results with a matching degree of ±1.5%. CONCLUSIONS Although the influences of low monitor unit values and daily output differences remain to be considered, the results suggest that the proposed approach can be clinically applied to expand treatment regions easily.

The Fungal Metabolite (+)-Terrein Abrogates Ovariectomy-Induced Bone Loss and Receptor Activator of Nuclear Factor-κB Ligand–Induced Osteoclastogenesis by Suppressing Protein Kinase-C α/βII Phosphorylation

Abstract: Osteoporosis is a common disease characterized by a systemic impairment of bone mass and microarchitecture that results in fragility fractures. Severe bone loss due to osteoporosis triggers pathological fractures and consequently decreases the daily life activity and quality of life. Therefore, prevention of osteoporosis has become an important issue to be addressed. We have reported that the fungal secondary metabolite (+)-terrein (TER), a natural compound derived from Aspergillus terreus, has shown receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation by suppressing nuclear factor of activated T-cell 1 (NFATc1) expression, a master regulator of osteoclastogenesis. TER has been shown to possess extensive biological and pharmacological benefits; however, its effects on bone metabolism remain unclear. In this study, we investigated the effects of TER on the femoral bone metabolism using a mouse-ovariectomized osteoporosis model (OVX mice) and then on RANKL signal transduction using mouse bone marrow macrophages (mBMMs). In vivo administration of TER significantly improved bone density, bone mass, and trabecular number in OVX mice (p < 0.01). In addition, TER suppressed TRAP and cathepsin-K expression in the tissue sections of OVX mice (p < 0.01). In an in vitro study, TER suppressed RANKL-induced phosphorylation of PKCα/βII, which is involved in the expression of NFATc1 (p < 0.05). The PKC inhibitor, GF109203X, also inhibited RANKL-induced osteoclastogenesis in mBMMs as well as TER. In addition, TER suppressed the expression of osteoclastogenesis-related genes, such as Ocstamp, Dcstamp, Calcr, Atp6v0d2, Oscar, and Itgb3 (p < 0.01). These results provide promising evidence for the potential therapeutic application of TER as a novel treatment compound against osteoporosis.

Comparison of edge enhancements by phase contrast imaging and post-processing with unsharp masking or Laplacian filtering

Abstract: Digital phase-contrast-imaging(phase-imaging)using a small-focus X-ray tube provides images with greater sharpness than conventional X-ray imaging(conventional-imaging), because the phase-imaging can produce images that are edge-enhanced at the boundary of an object because of refracted X-rays. In the present study, by performing image processing on a conventional-image we investigated whether we can produce an edge-enhanced conventional-image of equal edge-enhancement effect to that of phase-imaging. We used unsharp masking and Laplacian filtering as post-processing for edge enhancement of conventional-images. To determine the image processing parameters, the profile curves of acrylic fibers were used. Using these optimal imaging parameters, image processing was done on conventional-images of acrylic phantoms, followed by image quality comparisons of the post-processed conventional-images(post-processed-images)and phase-images. Furthermore, we performed a frequency analysis of the phase-image, conventional-image, and post-processedimage. Edge-enhanced conventional-images were obtained with a similar but slightly lower edge-enhancement effect than phase-images by processing images with appropriate parameters for unsharp masking and for Laplacian filtering. However, an increase in noise occurred because of the edge-enhancement processing. Edge-enhanced conventional-images of similar edge-enhancement effect to phase-images are obtainable by image processing of conventional-images. However, the edge clarity of the post-processed-images is somewhat worse than that of phase-images. Moreover, the edge-enhancement effect of post-processed-images is far lower than that of phase-images, because of increased noise resulting from the image processing.