- Comparison of pancreatic respiratory motion management with three abdominal corsets for particle radiation therapy: Case study. [Journal Article]
- JAJ Appl Clin Med Phys 2019 May 23
- CONCLUSIONS: Abdominal corsets may be effective devices to reduce pancreatic motion. For particle therapy, PE-based corsets are preferred over PU-based corset due to their material homogeneity and constant thickness.
- Development of pink-beam 4D phase CT for in-situ observation of polymers under infrared laser irradiation. [Journal Article]
- SRSci Rep 2019 May 22; 9(1):7404
- Four-dimensional phase computed tomography (4D phase CT) by an X-ray Talbot interferometer (XTI) with white synchrotron radiation has ever been demonstrated at a temporal resolution of about 1 s for …
Four-dimensional phase computed tomography (4D phase CT) by an X-ray Talbot interferometer (XTI) with white synchrotron radiation has ever been demonstrated at a temporal resolution of about 1 s for soft-matter samples. However, the radiation damage to samples caused by white synchrotron radiation occasionally hampers our understanding of the sample dynamical properties. Based on the fact that XTI functions with X-rays of a bandwidth up to ca. 10% with performance comparable to that by monochromatic X-rays, filtering white synchrotron radiation to generate a 'pink-beam' of a 10% bandwidth is effective to reduce radiation damage without degrading the image quality and temporal resolution. We have therefore developed pink-beam 4D phase CT at SPring-8, Japan by installing a multilayer mirror with a 10% bandwidth and a 25 keV central photon energy. XTI optimal at this photon energy was built downstream, and a CMOS-based X-ray detector was used to achieve fast image acquisitions with an exposure time of 1 ms (or 0.5 ms) per moiré image. The resultant temporal resolution of pink-beam 4D phase CT was 2 s (1 s). We applied the pink-beam 4D phase CT to in-situ observation of polypropylene, poly(methyl methacrylate), and polycarbonate under infrared laser irradiation (1064 nm). The dynamics of melting, bubbling, and ashing were successfully visualized in 3D movies without problematic radiation damage by synchrotron radiation.
- [Use of 4D-CT: Main technical aspects and clinical benefits]. [Journal Article]
- CRCancer Radiother 2019 May 18
- The four-dimensional scannography, also called 4D-CT, was created in the early 2000s. This method enables the aquistion of CT-scans synchronised with the patient's breathing. It allows an anatomical …
The four-dimensional scannography, also called 4D-CT, was created in the early 2000s. This method enables the aquistion of CT-scans synchronised with the patient's breathing. It allows an anatomical observation depending on the time. Different systems have been marketed. They are commonly used in treatment planning. It allows to take into account respiratory motion, considering the changes of shape and position of the tumor and organs. In the age of new techniques and stereotactic irradiations, 4D-CT is a valuable tool for estimating the uncertainties associated with respiratory movements, This technique also presents some limitations, including artifacts. The quality of the examination can be degraded in some patients with irregular respiration. Here we propose a summary of this technique detailing its principle of operation, its advantages and its main limits.
- High sensitivity and specificity of 4D-CTA in the detection of cranial arteriovenous shunts. [Journal Article]
- EREur Radiol 2019 May 14
- CONCLUSIONS: 4D-CTA has very high sensitivity and specificity for the detection of intracranial arteriovenous shunts. Based on these results, 4D-CTA may replace DSA imaging as a first modality in the diagnostic workup in a large number of patients suspected of a cranial dAVF or bAVM, especially if there is no doubt regarding the 4D-CTA diagnosis.• 4D-CTA was shown to have a high diagnostic accuracy and is an appropriate, less invasive replacement for DSA as a diagnostic tool for cranial arteriovenous shunts in the majority of suspected cases. • Doubt regarding the 4D-CTA result should prompt additional DSA imaging, as it is associated with false negatives. • False-positive 4D-CTA results are rare, but do exist.
- Four-Dimensional Scanning Transmission Electron Microscopy (4D-STEM): From Scanning Nanodiffraction to Ptychography and Beyond. [Journal Article]
- MMMicrosc Microanal 2019 May 14; :1-20
- Scanning transmission electron microscopy (STEM) is widely used for imaging, diffraction, and spectroscopy of materials down to atomic resolution. Recent advances in detector technology and computati…
Scanning transmission electron microscopy (STEM) is widely used for imaging, diffraction, and spectroscopy of materials down to atomic resolution. Recent advances in detector technology and computational methods have enabled many experiments that record a full image of the STEM probe for many probe positions, either in diffraction space or real space. In this paper, we review the use of these four-dimensional STEM experiments for virtual diffraction imaging, phase, orientation and strain mapping, measurements of medium-range order, thickness and tilt of samples, and phase contrast imaging methods, including differential phase contrast, ptychography, and others.
- Fetal whole-heart 4D imaging using motion-corrected multi-planar real-time MRI. [Journal Article]
- MRMagn Reson Med 2019 May 12
- CONCLUSIONS: The proposed methods show promise as a framework for motion-compensated 4D assessment of the fetal heart and great vessels.
- Non-contrast-enhanced magnetic resonance imaging for visualization and quantification of endovascular aortic prosthesis, their endoleaks and aneurysm sacs at 1.5 T. [Journal Article]
- MRMagn Reson Imaging 2019 May 07; 60:164-172
- CONCLUSIONS: Compared to DSA and CE-CTA, the proposed MRI methods provide improved anatomical and functional information for various types of endoprostheses and endoleaks. In addition, hemodynamic parameters of the aorta and information on the content of aneurysm sac are provided as well. Within the frame of personalized medicine, the personalized diagnosis enabled by this non-CE MRI protocol is the foundation for a personalized and successful treatment.
- Comparison of Planned Dose on Different CT Image Sets to Four-dimensional Monte Carlo Dose Recalculation Using the Patients Actual Breathing Trace for Lung Stereotactic Body Radiation Therapy. [Journal Article]
- MPMed Phys 2019 May 10
- CONCLUSIONS: We have developed a workow which, to our best knowledge, is the first incorporation of the patient breathing trace over the course of all individual treatment fractions with the Linac's log file information and 4D Monte Carlo recalculations of the actual treated dose. Due to the small patient cohort, no clear recommendation on which CT can be used for SBRT treatment planning can be given, but the developed workow, after adaption for clinical use, could be used to enhance a priori 4D Monte Carlo treatment planning in the future and help with the decision on which CT dataset treatment planning should be carried out. This article is protected by copyright. All rights reserved.
- Radiomic feature stability across 4D respiratory phases and its impact on lung tumor prognosis prediction. [Journal Article]
- PlosPLoS One 2019; 14(5):e0216480
- Radiomic analysis has recently demonstrated versatile uses in improving diagnostic and prognostic prediction accuracy for lung cancer. However, since lung tumors are subject to substantial motion due…
Radiomic analysis has recently demonstrated versatile uses in improving diagnostic and prognostic prediction accuracy for lung cancer. However, since lung tumors are subject to substantial motion due to respiration, the stability of radiomic features over the respiratory cycle of the patient needs to be investigated to better evaluate the robustness of the inter-patient feature variability for clinical applications, and its impact in such applications needs to be assessed. A full panel of 841 radiomic features, including tumor intensity, shape, texture, and wavelet features, were extracted from individual phases of a four-dimensional (4D) computed tomography on 20 early-stage non-small-cell lung cancer (NSCLC) patients. The stability of each radiomic feature was assessed across different phase images of the same patient using the coefficient of variation (COV). The relationship between individual COVs and tumor motion magnitude was inspected. Population COVs, the mean COVs of all 20 patients, were used to evaluate feature motion stability and categorize the radiomic features into 4 different groups. The two extremes, the Very Small group (COV≤5%) and the Large group (COV>20%), each accounted for about a quarter of the features. Shape features were the most stable, with COV≤10% for all features. A clinical study was subsequently conducted using 140 early-stage NSCLC patients. Radiomic features were employed to predict the overall survival with a 500-round bootstrapping. Identical multiple regression model development process was applied, and the model performance was compared between models with and without a feature pre-selection step based on 4D COV to pre-exclude unstable features. Among the systematically tested cutoff values, feature pre-selection with 4D COV≤5% achieved the optimal model performance. The resulting 3-feature radiomic model significantly outperformed its counterpart with no 4D COV pre-selection, with P = 2.16x10-27 in the one-tailed t-test comparing the prediction performances of the two models.
New Search Next
- Development of Direct-Laser-Printable Light-Powered Nanocomposites. [Journal Article]
- AAACS Appl Mater Interfaces 2019 May 14
- Four-dimensional (4D) printable light-powered materials have emerged as a new generation of materials for the development of functional devices. The design of these types of materials is mostly based…
Four-dimensional (4D) printable light-powered materials have emerged as a new generation of materials for the development of functional devices. The design of these types of materials is mostly based on the trans-cis transformation of azobenzene moieties in a liquid crystalline elastomer (LCE) matrix, in which the motion is triggered by ultraviolet (UV) irradiation. In this paper, we first report on a direct laser printable photoresist for producing light-powered 4D structures with enhanced mechanical properties and near-infrared (NIR) responsive mechanical deformation. The reported nanocomposite design is based on the photothermal effects of gold nanorods (AuNRs), which can induce the nematic-to-isotropic transition of LCE upon exposure to NIR irradiation. The miscibility between AuNRs and LCE is enhanced by thiol functionalization. Appropriate printing parameters are determined, and nanocomposites containing 0-3 wt % of AuNR loading are fabricated via femtosecond two-photon direct laser writing. The effects of the AuNR loading fraction and laser power on the light-powered actuating performance are evaluated. It is found that the nanocomposite with AuNR loading of 3 wt % demonstrates the maximum percentage (20%) of elongation under an NIR laser power of 2 W. An increase in laser power can lead to faster deformation but slower restoration. The nanocomposites demonstrate relatively good stability. Even after 300 actuation cycles, 80% of the elongation magnitude can be retained. In addition, an improvement of 80% in the complex modulus of the nanocomposites, due to the inclusion of AuNRs, is observed.