Kentaro Miki

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OBJECTIVE Pancreatic cancer is a difficult to treat disease with a persistently high mortality rate. We evaluated dose distribution simulation with respiratory-gated carbon-ion pencil beam scanning (C-PBS) with a simultaneous integrated boost (SIB) to increase tumour dose, sparing organs at risk (OARs). METHODS Using four-dimensional CT data of 12(More)
OBJECTIVE To assess the feasibility of treatment planning for pancreatic tumours subject to respiratory motion using field-specific target volumes (FTV) and field-specific organs at risk (FOAR) using four-dimensional computed tomography (4DCT). METHODS Fourteen pancreatic cancer patients underwent 4DCT. Radiation oncologists contoured the gross tumour(More)
PURPOSE Pancreatic tumor treatment dose distribution variations associated with supine and prone patient positioning were evaluated. METHODS A total of 33 patients with pancreatic tumors who underwent CT in the supine and prone positions were analyzed retrospectively. Gross tumor volume (GTV), planning target volume (PTV), and organs at risk (OARs)(More)
OBJECTIVE One approach to improving image quality of CT is to use metal artefact reduction image processing, such as single-energy metal artefact reduction (SEMAR). To quantify the impact of image correction on the quality of carbon-ion dose distribution, treatment planning using SEMAR was evaluated. METHODS Using a head phantom into which metal screws(More)
The accuracy of computed tomography number to electron density (CT-ED) calibration is a key component for dose calculations in an inhomogeneous medium. In a previous work, it was shown that the tolerance levels of CT-ED calibration became stricter with an increase in tissue thickness and decrease in the effective energy of a photon beam. For the last(More)
To extend layer-stacking irradiation to accommodate intrafractional organ motion, we evaluated the carbon-ion layer-stacking dose distribution using a numeric lung phantom. We designed several types of range compensators. The planning target volume was calculated from the respective respiratory phases for consideration of intrafractional beam range(More)
PURPOSE Having implemented amplitude-based respiratory gating for scanned carbon-ion beam therapy, we sought to evaluate its effect on positional accuracy and throughput. METHODS AND MATERIALS A total of 10 patients with tumors of the lung and liver participated in the first clinical trials at our center. Treatment planning was conducted with(More)
To improve treatment workflow, we developed a graphic processing unit (GPU)-based patient positional verification software application and integrated it into carbon-ion scanning beam treatment. Here, we evaluated the basic performance of the software. The algorithm provides 2D/3D registration matching using CT and orthogonal X-ray flat panel detector (FPD)(More)
Registration of patient anatomical structures to the reference position is a basic part of the patient set-up procedure. Registration of anatomical structures between the site of beam entrance on the patient surface and the distal target position is particularly important. Here, to improve patient positional accuracy during set-up for particle beam(More)
This study aimed to evaluate the loading of nutrients of agricultural origin. We investigated monthly nutrient concentrations at 11 stations located in the Hii River, Japan. The nitrogen and oxygen stable isotope ratios in nitrate were applied to distinguish the origin of nitrogen, i.e., from fertilizers applied to paddy fields or from sewage. Although(More)