Takashi Oritate

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Three-dimensional tumor position during rotational dose delivery was evaluated by acquiring in-treatment kilovoltage (kV) cone-beam CT (CBCT) to ensure treatment quality. The CBCT projection data of a phantom were acquired during rotational megavoltage (MV) dose delivery up to 6 Gy to evaluate image quality under MV beam irradiation. A lung tumor patient(More)
Quantitative studies with a single-crystal gamma camera often require correction for deadtime count loss. We evaluated the deadtime characteristics of a gamma camera using point sources. Point sources with various radioactivities were measured, and the relation between radioactivity and count rate was assessed. Two sources with different activities were(More)
Multi-detector computed tomography (MDCT) has rapidly evolved and is increasingly used for treatment simulation of thoracic and abdominal radiotherapy. A 320-detector row CT scanner has recently become available that allows axial volumetric scanning of a 16-cm-long range in a patient without table movement. Current radiotherapy techniques require a generous(More)
Physical characteristics of a dose calibrator CRC-30BC (Capintec, Mt. Vernon, N.Y.) was studied in the present study. We performed repeated measurements of the radioactive sample, changing its position in the well, its volume, and its radioactivity. In terms of the vertical dependence, the highest activity was obtained 7-8 cm from the bottom of the well.(More)
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