The polymer gel dosimeter has been proposed for use as a 3D dosimeter for complex dose distribution measurement of high dose-rate (HDR) brachytherapy. However, various shapes of catheter/applicator for sealed radioactive source transport used in clinical cases must be placed in the gel sample. The absorbed dose readout for the magnetic resonance (MR)-based polymer gel dosimeters requires calibration data for the dose-transverse relaxation rate (R2) response.
View Article and Find Full Text PDFBackground We investigated the early postoperative effect of percutaneous transluminal renal angioplasty on ambulatory blood pressure (BP) and the circadian characteristics of natriuresis and autonomic nerve activity. Methods and Results A total of 64 patients with hypertension with hemodynamically significant renal artery stenosis (mean age, 60.0±21.
View Article and Find Full Text PDFMedical linear-accelerator-based stereotactic radiosurgery (SRS) using a stereotactic apparatus or image-guided radiotherapy system for intracranial lesions is performed widely in clinical practice. In general, Winston-Lutz (WL) tests using films or electric portal imaging devices (EPIDs) have been performed as pre-treatment and routine quality assurance (QA) for the abovementioned treatment. Two-dimensional displacements between the radiation isocentre and mechanical isocentre are analysed from the test; therefore, it is difficult to identify the three-dimensional (3D) isocentre position intuitively.
View Article and Find Full Text PDFAngiopoietin (Ang) and its receptor, TIE signaling, contribute to the development and maturation of embryonic vasculature as well as vascular remodeling and permeability in adult tissues. Targeting both this signaling pathway and the major pathway with vascular endothelial growth factor (VEGF) is expected to permit clinical applications, especially in antiangiogenic therapies against tumors. Several drugs targeting the Ang-TIE signaling pathway in cancer patients are under clinical development.
View Article and Find Full Text PDFBackground: This study investigated the association between arterial stiffness indices and asymptomatic chronic kidney disease (CKD) risk categories in hypertensive patients.
Methods: Arterial stiffness indices, including 24-hour brachial and aortic systolic blood pressure (SBP) and pulse wave velocity (PWV), were measured by an oscillometric Mobil-O-Graph device, brachial-ankle PWV (baPWV) by a volume-plethysmographic method, and renal resistive index (RI) by ultrasonography, in 184 essential hypertensive patients (66.0 ± 17.
An optical configuration for Fabry-Pérot cavity scanning using a geometric phase shifter, known as the "spectral drill," is improved to acquire a spectrum in real-time. Previously, the resonance condition of the spectral drill is swept by the mechanical rotation of a phase plate comprising a geometric phase shifter, and the acquisition time is limited. In this work, using a q-plate and a camera instead of phase plate rotation and a photo detector, we remove all the spinning mechanics and increase the acquisition rate by a factor 720.
View Article and Find Full Text PDFDose distributions have become more complex with the introduction of image-guided brachytherapy in high-dose-rate (HDR) brachytherapy treatments. Therefore, to correctly execute HDR, conducting a quality assurance programme for the remote after-loading system and verifying the dose distribution in the patient treatment plan are necessary. The characteristics of the dose distribution of HDR brachytherapy are that the dose is high near the source and rapidly drops when the distance from the source increases.
View Article and Find Full Text PDFBackground: We investigated the effects of percutaneous transluminal renal angioplasty on left ventricular (LV) mass, and the impact of LV mass reduction on outcomes.
Methods: A total of 144 hypertensive patients with renal artery stenosis (RAS) (mean age 69 years; 22.2% fibromuscular dysplasia (FMD)) who underwent angioplasty were included.
Background: This study investigated the association between circadian hemodynamic characteristics and asymptomatic hypertensive organ damage.
Methods: Circadian hemodynamics, including 24-hour brachial and aortic systolic blood pressure (SBP), pulse wave velocity (PWV), augmentation index (AIx@75), cardiac index, and total vascular resistance (TVR), were evaluated using an oscillometric device, Mobil-O-Graph, in 284 essential hypertensive patients (67.8 ± 16.
Rapid technological advances in high-dose-rate brachytherapy have led to a requirement for greater accuracy in treatment planning system calculations and in the verification of dose distributions. In high-dose-rate brachytherapy, it is important to measure the dose distribution in the low-dose region at a position away from the source in addition to the high-dose range in the proximity of the source. The aim of this study was to investigate the accuracy of a treatment plan designed for prostate cancer in the low-dose range using a normoxic N-vinylpyrrolidone-based polymer gel (VIPET gel) dosimeter containing inorganic salt as a sensitizer (iVIPET).
View Article and Find Full Text PDFWe investigated the effect of magnesium chloride (MgCl) on the nuclear magnetic resonance dose-response of polyacrylamide-type (PAGAT, NIPAM, and VIPET) gel dosimeters containing acrylamide, N-isopropylacrylamide, and N-vinylpyrrolidone as a monomer, respectively. The dose-transverse relaxation rates (1/T = R) obtained from magnetic resonance imaging data revealed that a substantial increase in the dose-R response occurred as the concentration of MgCl in the gel dosimeters increased. The sensitivity of the PAGAT gel with 1.
View Article and Find Full Text PDFObjective: The present study aimed to compare circadian hemodynamic characteristics in hypertensive patients with and without primary aldosteronism.
Methods: Circadian hemodynamics, including 24-h brachial and central blood pressure (BP), SBP variability indices, central pulse wave velocity (PWV), augmentation index (AIx@75), cardiac index, and total vascular resistance (TVR), were evaluated using an oscillometric device, Mobil-O-Graph, in 60 patients with primary aldosteronism (63.4±13.
High-dose-rate (HDR) brachytherapy is performed with the remote after-loading system (RALS) to transport an Ir-192 source directly to inside or near the tumor. Quality assurance (QA) of equipment should be performed at sufficient frequency to ensuring safety and quality of HDR brachytherapy treatment. Polymer gel dosimeters have been attracting attention in recent years as a QA tools of HDR brachytherapy, because they can measure the three-dimensional steep dose gradients around HDR sources.
View Article and Find Full Text PDFEvaluation of dosimetric impact of the interplay effect between multi-leaf collimator (MLC) movement and tumor respiratory motion during volumetric modulated arc therapy (VMAT) delivery using polymer gel dosimeter was taken as an example in this article. An excellent gas barrier PAN (polyacrylonitrile) bottle filled with polyacrylamide-based gel dosimeter contained magnesium chloride as a sensitizer (iPAGAT dosimeter) was set to the QUASAR™ respiratory motion phantom (Modus), and was moved with motion amplitudes (peak-to-peak amplitude) of 1 and 2 cm with a 4 second period during VMAT delivery by the Novalis Tx linear accelerator (Varian/BrainLAB). Two spherical GTVs with 2 cm diameter and two PTVs were defined considering the respiratory motion and setup uncertainties.
View Article and Find Full Text PDFThis study investigated the effects of millimeter wave (MMW) irradiation with a wide range of frequencies on the proliferation and activity of normal human skin fibroblast (NB1RBG) and human glioblastoma (A172) cells. Very few studies have focused on low-power, long-term irradiation of cells with a widely tunable source. Our research examined non-thermal effects on cells exposed to radiation at low power with tunable frequencies from 70 GHz to 300 GHz.
View Article and Find Full Text PDFWith rapid advances being made in radiotherapy treatment, three-dimensional (3D) dose measurement techniques of great precision are required more than ever before. It is expected that 3D polymer gel dosimeters will satisfy clinical needs for an effective detector that can measure the complex 3D dose distributions. Polymer gel dosimeters are devices that utilize the radiation-induced polymerization reactions of vinyl monomers in a gel to store information about radiation dose.
View Article and Find Full Text PDFObjective: We investigated the impact of renal function on outcomes after percutaneous transluminal angioplasty.
Methods: A total of 139 hypertensive patients with atherosclerotic renal artery stenosis (mean age, 70 years, 80.6% men) who underwent renal percutaneous transluminal angioplasty were included.
This study investigated the optimum composition of the MAGAT polymer gel which is to be used in the quality assurance measurement of the thermal neutron, fast neutron and gamma ray components in the irradiation field used for boron neutron capture therapy at the Kyoto University Reactor. Simulations using the PHITS code showed that when combined with the gel, Li concentrations of 0, 10 and 100ppm were found to be potentially usable.
View Article and Find Full Text PDFThe natural course of idiopathic pulmonary fibrosis (IPF) is variable. Predicting disease progression and survival in IPF is important for treatment. We previously demonstrated that serum periostin has the potential to be a prognostic biomarker for IPF.
View Article and Find Full Text PDFThis study included 126 hypertensive patients with renal artery stenosis (mean age, 63 years; 22.2% fibromuscular dysplasia [FMD]) and investigated the effects of percutaneous transluminal renal angioplasty on office and home blood pressure (BP), and BP variability estimates derived from home BP, both at baseline and up to 12 months after angioplasty. Home BP was measured for 7 consecutive days, and the threshold defining uncontrolled home BP was ≥135/85 mm Hg.
View Article and Find Full Text PDFJ Hypertens
July 2016
Objective: Percutaneous transluminal renal angioplasty (PTA) is one of the standard treatments for renal artery stenosis (RAS). We investigated the frequency and risk factors for restenosis, and its impact on blood pressure (BP) control.
Methods: A total of 175 hypertensive patients with RAS [mean age 60 years; 34% women; 30.
Purpose: To identify candidates for PTRA in terms of the preservation of renal function, we herein evaluated factors that caused worsening renal function (WRF) after PTRA.
Methods: We evaluated 92 patients with atherosclerotic renal artery stenosis (mean age 70.7 ± 8.
Lymphatic metastasis of human malignant adenocarcinomas is a critical determinant of prognosis. Lymphangiogenesis, the growth of lymphatic vessels, is closely involved in lymphatic metastasis. However, the mechanisms of tumor lymphangiogenesis are not clearly understood.
View Article and Find Full Text PDFThe hottest frequency region in terms of research currently lies in the 'frequency gap' region between microwaves and infrared: terahertz waves. Although new methods for generating terahertz radiation have been developed, most sources cannot generate high-brightness terahertz beams. Here we demonstrate the generation of ultrabright terahertz waves (brightness ~0.
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