5 results on '"Daigo Kuroiwa"'
Search Results
2. Commissioning of a respiratory gating system involving a pressure sensor in carbon-ion scanning radiotherapy
- Author
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Hideyuki Mizuno, Osami Saito, Minoru Tajiri, Toshiyuki Shirai, Kentaro Miki, Taku Inaniwa, Daigo Kuroiwa, Mai Fukahori, Shigekazu Fukuda, and Taku Kimura
- Subjects
Respiratory-Gated Imaging Techniques ,Lung Neoplasms ,Materials science ,Supine position ,Threshold limit value ,87.55.Qr ,Acoustics ,Respiratory gating ,Beat (acoustics) ,Heavy Ion Radiotherapy ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Pressure ,Radiation Oncology Physics ,Humans ,Waveform ,Radiology, Nuclear Medicine and imaging ,pressure sensor ,Instrumentation ,Radiation ,Phantoms, Imaging ,Radiotherapy Planning, Computer-Assisted ,Respiration ,Radiotherapy Dosage ,Pressure sensor ,Prone position ,Amplitude ,respiratory gating ,030220 oncology & carcinogenesis ,Radiotherapy, Intensity-Modulated ,quality assurance in radiotherapy ,Algorithms - Abstract
This study reports the commissioning methodology and results of a respiratory gating system [AZ – 733 V/733 VI (Anzai Medical Co., Japan)] using a pressure sensor in carbon‐ion scanning radiotherapy. Commissioning includes choosing a location and method for pressure sensor installation, delay time measurement of the system, and the final flow test. Additionally, we proposed a methodology for the determination of a threshold level of generating an on/off gate for the beam to the respiratory waveform, which is important for clinical application. Regarding the location and method for installation of the pressure sensor, the actual person's abdomen, back of the body position, and supine/prone positioning were checked. By comparing the motion between the pressure sensor output and the reference LED sensor motion, the chest rear surface was shown to be unsuitable for the sensor installation, due to noise in the signal caused by the cardiac beat. Regarding delay time measurement of the system, measurements were performed for the following four steps: (a). Actual motion to wave signal generation; (b). Wave signal to gate signal generation; (c). Gate signal to beam on/off signal generation; (d). Beam on/off signal to the beam irradiation. The total delay time measured was 46 ms (beam on)/33 ms (beam off); these were within the prescribed tolerance time (
- Published
- 2018
3. Scanned carbon-ion beam therapy throughput over the first 7 years at National Institute of Radiological Sciences
- Author
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Tadashi Kamada, Toshiyuki Shirai, Takuji Furukawa, Yousuke Hara, Hiroshi Tsuji, Shinichiro Mori, Naoyoshi Yamamoto, Yuka Takei, Shigeru Yamada, Katsuyuki Tanimoto, Taku Inaniwa, Daigo Kuroiwa, Taku Kimura, and Minoru Tajiri
- Subjects
medicine.medical_specialty ,Time Factors ,Quality Assurance, Health Care ,Maintenance ,Carbon ion beam ,Biophysics ,General Physics and Astronomy ,Heavy Ion Radiotherapy ,Irradiation time ,Workflow ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Neoplasms ,Patient Handling ,Humans ,Medicine ,Radiology, Nuclear Medicine and imaging ,Medical physics ,Radiation treatment planning ,Throughput (business) ,Clinical Trials as Topic ,Contouring ,business.industry ,Radiotherapy Planning, Computer-Assisted ,General Medicine ,030220 oncology & carcinogenesis ,Radiological weapon ,business ,Quality assurance - Abstract
Introduction In the 7 years since our facility opened, we have treated >2000 patients with pencil-beam scanned carbon-ion beam therapy. Methods To summarize treatment workflow, we evaluated the following five metrics: i) total number of treated patients; ii) treatment planning time, not including contouring procedure; iii) quality assurance (QA) time (daily and patient-specific); iv) treatment room occupancy time, including patient setup, preparation time, and beam irradiation time; and v) daily treatment hours. These were derived from the oncology information system and patient handling system log files. Results The annual number of treated patients reached 594, 7 years from the facility startup, using two treatment rooms. Mean treatment planning time was 6.0 h (minimum: 3.4 h for prostate, maximum: 9.3 h for esophagus). Mean time devoted to daily QA and patient-specific QA were 22 min and 13.5 min per port, respectively, for the irradiation beam system. Room occupancy time was 14.5 min without gating for the first year, improving to 9.2 min (8.2 min without gating and 12.8 min with gating) in the second. At full capacity, the system ran for 7.5 h per day. Conclusions We are now capable of treating approximately 600 patients per year in two treatment rooms. Accounting for the staff working time, this performance appears reasonable compared to the other facilities.
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- 2018
4. Effects of chewing on cognitive processing speed
- Author
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Daigo Kuroiwa, Hiroo Ikehira, Minoru Onozuka, Yoshiyuki Hirano, Takayuki Obata, Hidehiko Takahashi, Toru Takahashi, and Atsumichi Tachibana
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Adult ,Male ,medicine.medical_specialty ,Cognitive Neuroscience ,Short-term memory ,Poison control ,Experimental and Cognitive Psychology ,Neuropsychological Tests ,Audiology ,Developmental psychology ,Chewing Gum ,Executive Function ,Young Adult ,Arts and Humanities (miscellaneous) ,Reaction Time ,Developmental and Educational Psychology ,medicine ,Humans ,Attention ,Effects of sleep deprivation on cognitive performance ,Anterior cingulate cortex ,Working memory ,Motor control ,Cognition ,Magnetic Resonance Imaging ,Frontal Lobe ,Alertness ,Neuropsychology and Physiological Psychology ,medicine.anatomical_structure ,Mastication ,Female ,Psychology ,Psychomotor Performance - Abstract
In recent years, chewing has been discussed as producing effects of maintaining and sustaining cognitive performance. We have reported that chewing may improve or recover the process of working memory; however, the mechanisms underlying these phenomena are still to be elucidated. We investigated the effect of chewing on aspects of attention and cognitive processing speed, testing the hypothesis that this effect induces higher cognitive performance. Seventeen healthy adults (20-34 years old) were studied during attention task with blood oxygenation level-dependent functional (fMRI) at 3.0 T MRI. The attentional network test (ANT) within a single task fMRI containing two cue conditions (no cue and center cue) and two target conditions (congruent and incongruent) was conducted to examine the efficiency of alerting and executive control. Participants were instructed to press a button with the right or left thumb according to the direction of a centrally presented arrow. Each participant underwent two back-to-back ANT sessions with or without chewing gum, odorless and tasteless to remove any effect other than chewing. Behavioral results showed that mean reaction time was significantly decreased during chewing condition, regardless of speed-accuracy trade-off, although there were no significant changes in behavioral effects (both alerting and conflict effects). On the other hand, fMRI analysis revealed higher activations in the anterior cingulate cortex and left frontal gyrus for the executive network and motor-related regions for both attentional networks during chewing condition. These results suggested that chewing induced an increase in the arousal level and alertness in addition to an effect on motor control and, as a consequence, these effects could lead to improvements in cognitive performance.
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- 2013
5. Variation in patient position and impact on carbon-ion scanning beam distribution during prostate treatment
- Author
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Shinichiro Mori, Y Shiraishi, Daigo Kuroiwa, Kouichi Shibayama, M Nakao, Hiroshi Tsuji, Minoru Tajiri, Taku Inaniwa, Katsuyuki Tanimoto, and Kentaro Miki
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Male ,Full Paper ,business.industry ,Radiography ,Radiotherapy Planning, Computer-Assisted ,Prostatic Neoplasms ,Heavy Ion Radiotherapy ,Radiotherapy Dosage ,General Medicine ,Scanning beam ,Patient Positioning ,medicine.anatomical_structure ,Prostate ,Position (vector) ,medicine ,Relative biological effectiveness ,Distribution (pharmacology) ,Humans ,Radiology, Nuclear Medicine and imaging ,In patient ,Tomography ,business ,Nuclear medicine ,Tomography, X-Ray Computed - Abstract
We assessed the impact of changes in patient position on carbon-ion scanning beam distribution during treatment for prostate cancer.68 patients were selected. Carbon-ion scanning dose was calculated. Two different planning target volumes (PTVs) were defined: PTV1 was the clinical target volume plus a set-up margin for the anterior/lateral sides and posterior side, while PTV2 was the same as PTV1 minus the posterior side. Total prescribed doses of 34.4 Gy [relative biological effectiveness (RBE)] and 17.2 Gy (RBE) were given to PTV1 and PTV2, respectively. To estimate the influence of geometric variations on dose distribution, the dose was recalculated on the rigidly shifted single planning CT based on two dimensional-three dimensional rigid registration of the orthogonal radiographs before and after treatment for the fraction of maximum positional changes.Intrafractional patient positional change values averaged over all patients throughout the treatment course were less than the target registration error = 2.00 mm and angular error = 1.27°. However, these maximum positional errors did not occur in all 12 treatment fractions. Even though large positional changes occurred during irradiation in all treatment fractions, lowest dose encompassing 95% of the target (D95)-PTV1 was98% of the prescribed dose.Intrafractional patient positional changes occurred during treatment beam irradiation and degraded carbon-ion beam dose distribution. Our evaluation did not consider non-rigid deformations, however, dose distribution was still within clinically acceptable levels.Inter- and intrafractional changes did not affect carbon-ion beam prostate treatment accuracy.
- Published
- 2015
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