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  • Oxford University Press (OUP)  (7)
  • 2020-2024  (7)
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  • Oxford University Press (OUP)  (7)
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  • 2020-2024  (7)
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  • 1
    Online-Ressource
    Online-Ressource
    Feasibility of synthetic computed tomography generated with an adversarial network for multi-sequence magnetic resonance-based brain radiotherapy
    Oxford University Press (OUP) ; 2020
    In:  Journal of Radiation Research Vol. 61, No. 1 ( 2020-01-23), p. 92-103
    Details
    In: Journal of Radiation Research, Oxford University Press (OUP), Vol. 61, No. 1 ( 2020-01-23), p. 92-103
    Kurzfassung: The aim of this work is to generate synthetic computed tomography (sCT) images from multi-sequence magnetic resonance (MR) images using an adversarial network and to assess the feasibility of sCT-based treatment planning for brain radiotherapy. Datasets for 15 patients with glioblastoma were selected and 580 pairs of CT and MR images were used. T1-weighted, T2-weighted and fluid-attenuated inversion recovery MR sequences were combined to create a three-channel image as input data. A conditional generative adversarial network (cGAN) was trained using image patches. The image quality was evaluated using voxel-wise mean absolute errors (MAEs) of the CT number. For the dosimetric evaluation, 3D conformal radiotherapy (3D-CRT) and volumetric modulated arc therapy (VMAT) plans were generated using the original CT set and recalculated using the sCT images. The isocenter dose and dose–volume parameters were compared for 3D-CRT and VMAT plans, respectively. The equivalent path length was also compared. The mean MAEs for the whole body, soft tissue and bone region were 108.1 ± 24.0, 38.9 ± 10.7 and 366.2 ± 62.0 hounsfield unit, respectively. The dosimetric evaluation revealed no significant difference in the isocenter dose for 3D-CRT plans. The differences in the dose received by 2% of the volume (D2%), D50% and D98% relative to the prescribed dose were  & lt;1.0%. The overall equivalent path length was shorter than that for real CT by 0.6 ± 1.9 mm. A treatment planning study using generated sCT detected only small, clinically negligible differences. These findings demonstrated the feasibility of generating sCT images for MR-only radiotherapy from multi-sequence MR images using cGAN.
    Materialart: Online-Ressource
    ISSN: 0449-3060 , 1349-9157
    URL: Article
    DOI: 10.1093/jrr/rrz063
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2020
    ZDB Id: 2038914-0
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Online-Ressource
    Online-Ressource
    Impact of bleeding on mortality in patients with acute myocardial infarction complicated by cardiogenic shock
    Oxford University Press (OUP) ; 2021
    In:  European Heart Journal. Acute Cardiovascular Care Vol. 10, No. 4 ( 2021-05-25), p. 388-396
    Details
    In: European Heart Journal. Acute Cardiovascular Care, Oxford University Press (OUP), Vol. 10, No. 4 ( 2021-05-25), p. 388-396
    Kurzfassung: Acute myocardial infarction complicated by cardiogenic shock (AMICS) is associated with substantial mortality, although there are limited data available on bleeding in this critical condition. This study sought to investigate the incidence and impact of major in-hospital bleeding on all-cause mortality in patients with AMICS who undergo percutaneous coronary intervention (PCI). Methods and results Between 2015 and 2017, a total of 3411 patients hospitalized within 24 h after symptom onset were prospectively enrolled in the Japan Acute Myocardial Infarction Registry (JAMIR) and followed up for a median of 293 (interquartile range, 22–375) days. AMICS developed in 335 (9.8%) patients (mean age, 71.3 ± 13.6 years). Overall, the rate of major in-hospital bleeding (Bleeding Academic Research Consortium types 3 and 5) and in-hospital mortality was 14.6% and 28.7%, respectively. The majority of major in-hospital bleeding (73.5%) occurred within 48 h after PCI. Compared to patients without major in-hospital bleeding, those with it had higher rates of renal failure, left main coronary artery culprit lesion, and intra-aortic balloon pump or extracorporeal membrane oxygenation support, and had longer door-to-device time. The cumulative incidence of 1-year all-cause mortality was significantly higher in the major bleeding group compared to the non-major bleeding group (63.8% vs. 25.5%; log-rank P  & lt; 0.001). After adjusting for confounders, major in-hospital bleeding was independently associated with increased all-cause mortality (hazard ratio, 1.70; 95% confidence interval, 1.08–2.69). Conclusions These findings of JAMIR indicate that major in-hospital bleeding is associated with all-cause mortality in patients with AMICS who undergo PCI.
    Materialart: Online-Ressource
    ISSN: 2048-8726 , 2048-8734
    URL: Article
    DOI: 10.1093/ehjacc/zuab014
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2021
    ZDB Id: 2663340-1
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Online-Ressource
    Online-Ressource
    Prediction of sudden cardiac death in Japanese heart failure patients: international validation of the Seattle Proportional Risk Model
    Oxford University Press (OUP) ; 2020
    In:  EP Europace Vol. 22, No. 4 ( 2020-04-01), p. 588-597
    Details
    In: EP Europace, Oxford University Press (OUP), Vol. 22, No. 4 ( 2020-04-01), p. 588-597
    Kurzfassung: Heart failure (HF) is associated with an increased risk of sudden cardiac death (SCD). This study sought to demonstrate the incidence of SCD within a multicentre Japanese registry of HF patients hospitalized for acute decompensation, and externally validate the Seattle Proportional Risk Model (SPRM). Methods and results We consecutively registered 2240 acute HF patients from academic institutions in Tokyo, Japan. The discrimination and calibration of the SPRM were assessed by the c-statistic, Hosmer–Lemeshow statistic, and visual plotting among non-survivors. Patient-level SPRM predictions and implantable cardioverter-defibrillator (ICD) benefit [ICD estimated hazard ratio (HR), derived from the Cox proportional hazards model in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)] was calculated. During the 2-year follow-up, 356 deaths (15.9%) occurred, which included 76 adjudicated SCDs (3.4%) and 280 non-SCDs (12.5%). The SPRM showed acceptable discrimination [c-index = 0.63; 95% confidence interval (CI) 0.56–0.70] , similar to that of original SPRM-derivation cohort. The calibration plot showed reasonable conformance. Among HF patients with reduced ejection fraction (EF; & lt; 40%), SPRM showed improved discrimination compared with the ICD eligibility criteria (e.g. New York Heart Association functional Class II–III with EF ≤ 35%): c-index = 0.53 (95% CI 0.42–0.63) vs. 0.65 (95% CI 0.55–0.75) for SPRM. Finally, in the subgroup of 246 patients with both EF ≤ 35% and SPRM-predicted risk of ≥ 42.0% (SCD-HeFT defined ICD benefit threshold), mean ICD estimated HR was 0.70 (30% reduction of all-cause mortality by ICD). Conclusion The cumulative incidence of SCD was 3.4% in Japanese HF registry. The SPRM performed reasonably well in Japanese patients and may aid in improving SCD prediction.
    Materialart: Online-Ressource
    ISSN: 1099-5129 , 1532-2092
    URL: Article
    DOI: 10.1093/europace/euaa002
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2020
    ZDB Id: 2002579-8
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Online-Ressource
    Online-Ressource
    Correction of lateral response artifacts from flatbed scanners for dual-channel radiochromic film dosimetry
    Oxford University Press (OUP) ; 2021
    In:  Journal of Radiation Research Vol. 62, No. 2 ( 2021-03-10), p. 319-328
    Details
    In: Journal of Radiation Research, Oxford University Press (OUP), Vol. 62, No. 2 ( 2021-03-10), p. 319-328
    Kurzfassung: In this study, we evaluated the inter-unit variability of the lateral response artifact for multiple flatbed scanners, focusing on the dual-channel method, and investigated the correction method of the lateral non-uniformity. Four scanners with A3+ paper-size and five scanners with A4 paper-size were evaluated. To generate the dose–response curves, small pieces of the Gafchromic EBT3 and EBT-XD films were irradiated, and five of the pieces were repeatedly scanned by moving them on the scanner to evaluate the lateral non-uniformity. To calculate the dose distribution accounting for the lateral non-uniformity, linear functions of the correction factor, representing the difference between the pixel values at offset position and the scanner midline, were calculated for red and blue color channels at each lateral position. Large variations of the lateral non-uniformity among the scanners were observed, even for the same model of scanner. For high dose, red color showed pixel value profiles similar to symmetric curves, whereas the profiles for low dose were asymmetric. The peak positions changed with dose. With correction of the lateral non-uniformity, the dose profiles of the pyramidal dose distribution measured at various scanner positions and that calculated with a treatment planning system showed almost identical profile shapes at all high-, middle- and low-dose levels. The dual-channel method used in this study showed almost identical dose profiles measured with all A3+ and A4 paper-size scanners at any positions when the corrections were applied for each color channel.
    Materialart: Online-Ressource
    ISSN: 0449-3060 , 1349-9157
    URL: Article
    DOI: 10.1093/jrr/rraa124
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2021
    ZDB Id: 2038914-0
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Online-Ressource
    Online-Ressource
    Characteristics of microSilicon diode detector for electron beam dosimetry
    Oxford University Press (OUP) ; 2021
    In:  Journal of Radiation Research ( 2021-09-24)
    Details
    In: Journal of Radiation Research, Oxford University Press (OUP), ( 2021-09-24)
    Kurzfassung: A microSilicon™ (PTW type 60023), a new unshielded diode detector succeeding Diode E (model 60017, PTW), was characterized for electron beam dosimetry and compared with other detectors. Electron beams generated from a TrueBeam linear accelerator were measured using the microSilicon, Diode E, and microDiamond synthetic single-crystal diamond detector. Positional accuracy of microSilicon was measured by data collected in air and water. The percent depth dose (PDD), off-center ratio (OCR), dose–response linearity, dose rate dependence, and cone factors were evaluated. The PDDs were compared with data measured using a PPC40 plane-parallel ionization chamber. The maximum variations of depth of 50% and 90% of the maximum dose, and practical depth among all detectors and energies were 0.9 mm. The maximum variations of the bremsstrahlung dose among all detectors and energies were within 0.3%. OCR showed good agreement within 1% for the flat and tail regions. The microSilicon detector showed a penumbra width similar to microDiamond, whereas Diode E showed the steepest penumbra shape. All detectors showed good dose–response linearity and stability against the dose rate; only Diode E demonstrated logarithmic dose rate dependency. The cone factor measured with microSilicon was within ±1% for all energies and cone sizes. We demonstrated that the characteristics of microSilicon is suitable for electron beam dosimetry. The microSilicon detector can be a good alternative for electron beam dosimetry in terms of providing an appropriate PDD curve without corrections, high spatial resolution for OCR measurements and cone factors.
    Materialart: Online-Ressource
    ISSN: 0449-3060 , 1349-9157
    URL: Article
    DOI: 10.1093/jrr/rrab085
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2021
    ZDB Id: 2038914-0
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Online-Ressource
    Online-Ressource
    Diagnostic performance of magnifying blue laser imaging versus magnifying narrow-band imaging for identifying the depth of invasion of superficial esophageal squamous cell carcinoma
    Oxford University Press (OUP) ; 2021
    In:  Diseases of the Esophagus Vol. 34, No. 3 ( 2021-03-08)
    Details
    In: Diseases of the Esophagus, Oxford University Press (OUP), Vol. 34, No. 3 ( 2021-03-08)
    Kurzfassung: Identifying the depth of invasion (DOI) of superficial esophageal squamous cell carcinoma (SESCC) is crucial to determine the indication for endoscopic resection. This retrospective, single-center study aimed to evaluate the diagnostic efficacy of magnifying blue laser imaging (M-BLI) compared with white-light imaging (WLI) or magnifying narrow-band imaging (M-NBI) for identifying the DOI of SESCC. A total of 160 consecutive patients with SESCCs who underwent endoscopic submucosal dissection were enrolled in this study. Still images of the lesion were obtained using WLI, M-BLI and M-NBI prior to endoscopic submucosal dissection. Three endoscopists retrospectively evaluated the DOI using WLI according to non-magnifying findings and using M-BLI and M-NBI images according to the magnifying endoscopic classification of the Japan Esophageal Society. The diagnostic accuracy of each modality was compared using the chi-square test. The DOIs in 160 SESCCs evaluated pathologically were as follows: invasion to the epithelium or lamina propria mucosa in 130, invasion to the lamina muscularis mucosa or submucosa to a depth ≤ 200 μm in 18, and invasion to the submucosa to a depth  & gt; 200 μm in 12. The overall diagnostic accuracy rates of WLI, M-BLI, M-NBI, WLI with M-BLI (WLI + M-BLI), and WLI with M-NBI (WLI + M-NBI) were 86.9, 91.2, 90.6, 95.6 and 94.4%, respectively. Significant differences were found between WLI and WLI + M-BLI or WLI + M-NBI (P = 0.006 and P = 0.021, respectively). The concordance of intrapapillary capillary loops between M-BLI and M-NBI was 91.2%. The kappa coefficients for interobserver variability of the three endoscopists for M-BLI and M-NBI were 0.728/0.649/0.792 and 0.729/0.666/0.791, respectively, while those for intraobserver variability were 0.919/0.746/0.778 and 0.736/0.720/0.745, respectively. Similar to M-NBI, M-BLI was useful in predicting the DOI of SESCCs.
    Materialart: Online-Ressource
    ISSN: 1120-8694 , 1442-2050
    URL: Article
    DOI: 10.1093/dote/doaa078
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2021
    ZDB Id: 2004949-3
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Online-Ressource
    Online-Ressource
    Characterization of a microSilicon diode detector for small-field photon beam dosimetry
    Oxford University Press (OUP) ; 2020
    In:  Journal of Radiation Research Vol. 61, No. 3 ( 2020-05-22), p. 410-418
    Details
    In: Journal of Radiation Research, Oxford University Press (OUP), Vol. 61, No. 3 ( 2020-05-22), p. 410-418
    Kurzfassung: This study characterized a new unshielded diode detector, the microSilicon (model 60023), for small-field photon beam dosimetry by evaluating the photon beams generated by a TrueBeam STx and a CyberKnife. Temperature dependence was evaluated by irradiating photons and increasing the water temperature from 11.5 to 31.3°C. For Diode E, microSilicon, microDiamond and EDGE detectors, dose linearity, dose rate dependence, energy dependence, percent-depth-dose (PDD), beam profiles and detector output factor (OFdet) were evaluated. The OFdet of the microSilicon detector was compared to the field output factors of the other detectors. The microSilicon exhibited small temperature dependence within 0.4%, although the Diode E showed a linear variation with a ratio of 0.26%/°C. The Diode E and EDGE detectors showed positive correlations between the detector reading and dose rate, whereas the microSilicon showed a stable response within 0.11%. The Diode E and microSilicon demonstrated negative correlations with the beam energy. The OFdet of microSilicon was the smallest among all the detectors. The maximum differences between the OFdet of microSilicon and the field output factors of microDiamond were 2.3 and 1.6% for 5 × 5 mm2 TrueBeam and 5 mm φ CyberKnife beams, respectively. The PDD data exhibited small variations in the dose fall-off region. The microSilicon and microDiamond detectors yielded similar penumbra widths, whereas the other detectors showed steeper penumbra profiles. The microSilicon demonstrated favorable characteristics including small temperature and dose rate dependence as well as the small spatial resolution and output factors suitable for small field dosimetry.
    Materialart: Online-Ressource
    ISSN: 0449-3060 , 1349-9157
    URL: Article
    DOI: 10.1093/jrr/rraa010
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2020
    ZDB Id: 2038914-0
    Standort Signatur Einschränkungen Verfügbarkeit
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    Online-Ressource
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