Publications by authors named "Jun Kataoka"

To confirm the performance improvement of virtual monoenergetic images (VMIs) for iodine contrast tasks in a clinical photon-counting detector CT (PCD CT) using Fourier-based assessment, compared with those in the latest-generation dual-source dual-energy CT (DECT). A water-filled bath with a diameter of 300 mm, which contains rod-shaped phantoms equivalent to diluted iodine (2 and 12 mg/mL), was scanned using PCD CT and DECT at 15, 7.5, and 3 mGy.

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Prompt gammas imaging (PGI) is a promising method for observing a beam's shape and estimating the range of the beam from outside a subject. However 2-dimensional images of prompt gammas (PGs) during irradiation of protons were still difficult to measure. To achieve PGI, we developed a new gamma camera and imaged PGs while irradiating a phantom by proton beams.

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Background and objective Although early diuretic use and negative fluid balance (NFB) have been associated with lower mortality in mechanically ventilated patients, some patients are not tolerant to NFB. Little is known about whether urine output response after the diuretic administration predicts NFB tolerance in mechanically ventilated patients. Hence, we conducted this study to look into this.

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This research aimed to identify materials capable of emitting visible light useful for dose management at ultra-high dose rate (uHDR). Various materials were irradiated with proton beams at a normal dose rate (NDR) and uHDR, and the resulting surface luminescence was captured using a high-sensitivity camera. The luminescence images were compared with the corresponding dose distributions.

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Transanal total mesorectal excision (taTME) has improved the laparoscopic dissection for rectal cancer in the narrow pelvis. Although taTME has more clinical benefits than laparoscopic surgery, such as a better view of the distal rectum and direct determination of distal resection margin, an intraoperative urethral injury could occur in excision ta-TME. This study aimed to determine the feasibility and efficacy of the ta-TME with IRIS U kit surgery.

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Article Synopsis
  • Real-time monitoring of radiation therapy beams aimed at patients is challenging due to a lack of external observation methods.
  • Researchers discovered that polyester fabrics can serve as effective scintillating materials to visualize radiation beams, producing light outputs comparable to traditional plastic scintillators.
  • By using CMOS cameras, clear images of proton beam spots on polyester cloths were captured, paving the way for improved surface beam imaging in radiation therapy.
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We elucidate the decomposition mechanism of hydrogen peroxide, which is formed by water radiolysis, by gold nanoparticles (GNPs) under X-ray irradiation. The variations in yields of hydrogen peroxide generated in the presence of GNPs are evaluated using the Ghormley technique. The increase of yields of OH radicals has been quantified using Ampliflu® Red solutions.

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Article Synopsis
  • A new system was created to simultaneously measure three imaging methods—prompt gamma photons, prompt x-rays, and induced positrons—during proton beam therapy using a phantom model.
  • The imaging setup includes a gamma camera, an x-ray camera, and a dual-head PET system to analyze these modalities under controlled conditions.
  • Results showed that induced positrons had the highest image quality, and the system can provide valuable data for enhancing proton beam shape estimation in therapeutic applications.
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High-resolution and real-time imaging of particle ion trajectories is essential in nuclear medicine and nuclear engineering. One potential method to achieve high-resolution real-time trajectory imaging of particle ions involves utilizing an imaging system that integrates a scintillator plate with a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera. However, acquiring an EM-CCD camera might prove challenging due to the discontinuation of CCD sensor manufacturing by vendors.

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High sensitivity and high resolution is desired in such technologies as neutron radiography. However, the contamination of gamma photons in neutron images decreases the accuracy of neutron radiography. To solve this problem, we developed an event-by-event based neutron imaging system that can selectively detect neutrons.

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Objectives: This study aimed to examine the association between ABCDEF bundles and long-term postintensive care syndrome (PICS)-related outcomes.

Design: Secondary analysis of the J-PICS study.

Setting: This study was simultaneously conducted in 14 centers and 16 ICUs in Japan between April 1, 2019, and September 30, 2019.

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Article Synopsis
  • * A double pix2pix model was developed: one model denoises the images while the other enhances resolution, significantly improving the accuracy of estimated images.
  • * Results showed that with the new method, the difference in source size estimation was reduced to about 0.5 mm, even at shorter measurement times, making it a promising approach for real-time monitoring during treatments.
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Article Synopsis
  • - Osmotic demyelination syndrome (ODS) can occur in patients with diabetes and low sodium levels (hyponatremia), as shown in a case study involving a 74-year-old man with cirrhosis and uncontrolled type 2 diabetes.
  • - The patient developed altered mental status and chorea during treatment for diabetic ketoacidosis (DKA), even without rapid correction of sodium levels or initial MRI changes.
  • - Clinicians need to be aware of ODS in DKA patients who exhibit unconsciousness and neurological symptoms, like chorea, and should consider follow-up MRI to detect any later complications.
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Introduction And Importance: Lateral lymph node dissection (LLND) for recurrent lateral pelvic lymph node metastasis could be the only surgical treatment to improve its prognosis, but is difficult and challenging technically.

Case Presentation: A 75-year-old Japanese man who underwent a radical laparoscopic intersphincteric resection to treat double lower rectal cancer. Computed tomography and MRI showed lower rectal wall thickening and bilateral lateral lymph node swelling.

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Recently, in-beam positron emission tomography (PET) has been actively researched for reducing biological washout effects and dose monitoring during irradiation. However, the positron distribution does not precisely reflect the dose distribution since positron production and ionization are completely different physical processes. Thus, a novel in-beam system was proposed to determine proton dose range by measuring scattered protons with dozens of scintillation detectors surrounding the body surface.

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FLASH radiation therapy with ultrahigh dose rates (UHDR) has the potential to reduce damage to normal tissue while maintaining anti-tumor efficacy. However, rapid and precise dose distribution measurements remain difficult for FLASH radiation therapy with proton beams. To solve this problem, we performed luminescence imaging of water following irradiation by a UHDR proton beam captured using a charge-coupled device camera.

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Prompt x-ray imaging is a promising method for observing the beam shape from outside a subject. However, its distribution is different from dose distribution, and thus a comparison with the dose is required. Meanwhile, luminescence imaging of water is a possible method for imaging the dose distribution.

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. Prompt x-ray imaging using a low-energy x-ray camera is a promising method for observing a proton beam's shape from outside the subject. Furthermore, imaging of positrons produced by nuclear reactions with protons is a possible method for observing the beam shape.

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High-resolution imaging of alpha particles is required in the detection of alpha radionuclides in cells or small organs for the development of radio-compounds for targeted alpha-particle therapy or other purposes. We developed an ultrahigh resolution, real time alpha-particle imaging system for observing the trajectories of alpha particles in a scintillator. The developed system is based on a magnifying unit and a cooled electron multiplying charge-coupled device (EM-CCD) camera, combined with a 100-µm-thick Ce-doped GdAlGaO (GAGG) scintillator plate.

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Prompt secondary electron bremsstrahlung X-ray (prompt X-ray) imaging using a low-energy X-ray camera is a promising method for observing a beam shape from outside the subject. However, such imaging has so far been conducted only for pencil beams without a multi-leaf collimator (MLC). The use of spread-out Bragg peak (SOBP) with an MLC may increase the scattered prompt gamma photons and decrease the contrast of the images of prompt X-rays.

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Introduction: and importance: TEP might be one of options for treating such a sports hernia.

Case Presentation: An 18-year-old Japanese male presented with right groin pain for approximately two years. The pain was initially felt on the right side only, especially on kicking.

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Purpose: Although real-time imaging of the high-activity iridium-192 (Ir-192) source position during high-dose-rate (HDR) brachytherapy using a high-energy gamma camera system is a promising approach, the energy window was not optimized for spatial resolution or scatter fraction.

Methods: By using a list-mode data-acquisition system that can acquire energy information of a cerium-doped yttrium aluminum perovskite (YA1O: YAP(Ce)) gamma camera, we tried to optimize the energy window's setting to improve the spatial resolution and reduce scatter fraction.

Results: The spatial resolution was highest for the central energy of the window at ∼300 keV.

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The prevalence of burnout among critical care professionals during the coronavirus disease (COVID-19) pandemic varies in different countries. To investigate the prevalence of burnout and turnover intention in Japanese critical care professionals in March 2021. This cross-sectional study used a web-based survey of Japanese critical care professionals working in 15 intensive care units in 15 prefectures.

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Article Synopsis
  • The study aimed to measure the dwell time and moving speed of a high-activity iridium-192 (Ir-192) source used in HDR brachytherapy to ensure accurate tumor dose delivery.
  • A gamma camera system was employed, utilizing list-mode imaging to capture quick sequential images, which facilitated the evaluation of dwell times and speeds of the Ir-192 source.
  • Results indicated that the system could accurately measure dwell times and moving speeds, with specific findings showing consistent measurements and an observed increase in speed relative to the distance from the dwell position.
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