Effect of radiation induced current on the quality of MR images in an integrated linac-MR system

2012 ◽  
Vol 39 (10) ◽  
pp. 6139-6147 ◽  
Author(s):  
Ben Burke ◽  
K. Wachowicz ◽  
B. G. Fallone ◽  
Satyapal Rathee
Keyword(s):  
Induced Current ◽  
Mr Images ◽  
Radiation Induced

TH-E-BRA-09: Radiation Induced Current Effects on MR Images from an Integrated Linac-MR System

2012 ◽  
Vol 39 (6Part31) ◽  
pp. 4013-4013
Author(s):  
B Burke ◽  
K Wachowicz ◽  
B Fallone ◽  
S Rathee
Keyword(s):  
Induced Current ◽  
Mr Images ◽  
Radiation Induced

scholarly journals Overestimation of grey matter atrophy in glioblastoma patients following radio(chemo)therapy

2021 ◽  
Author(s):  
A. Gommlich ◽  
F. Raschke ◽  
J. Petr ◽  
A. Seidlitz ◽  
C. Jentsch ◽  
...  
Keyword(s):  
Brain Tumour ◽  
Contralateral Hemisphere ◽  
Mr Images ◽  
Segmentation Accuracy ◽  
Volume Measurements ◽  
Radiation Induced ◽  
The Mean ◽  
Changes Over Time ◽  
Grey Matter Atrophy ◽  
Abnormal Tissue

Abstract Objective Brain atrophy has the potential to become a biomarker for severity of radiation-induced side-effects. Particularly brain tumour patients can show great MRI signal changes over time caused by e.g. oedema, tumour progress or necrosis. The goal of this study was to investigate if such changes affect the segmentation accuracy of normal appearing brain and thus influence longitudinal volumetric measurements. Materials and methods T1-weighted MR images of 52 glioblastoma patients with unilateral tumours acquired before and three months after the end of radio(chemo)therapy were analysed. GM and WM volumes in the contralateral hemisphere were compared between segmenting the whole brain (full) and the contralateral hemisphere only (cl) with SPM and FSL. Relative GM and WM volumes were compared using paired t tests and correlated with the corresponding mean dose in GM and WM, respectively. Results Mean GM atrophy was significantly higher for full segmentation compared to cl segmentation when using SPM (mean ± std: ΔVGM,full = − 3.1% ± 3.7%, ΔVGM,cl = − 1.6% ± 2.7%; p < 0.001, d = 0.62). GM atrophy was significantly correlated with the mean GM dose with the SPM cl segmentation (r = − 0.4, p = 0.004), FSL full segmentation (r = − 0.4, p = 0.004) and FSL cl segmentation (r = -0.35, p = 0.012) but not with the SPM full segmentation (r = − 0.23, p = 0.1). Conclusions For accurate normal tissue volume measurements in brain tumour patients using SPM, abnormal tissue needs to be masked prior to segmentation, however, this is not necessary when using FSL.

Defect Reduction and Defect Engineering in Silicon-on-Sapphire Material Using Ge Implantation

1990 ◽  
Vol 201 ◽  
Author(s):  
F. Namavar ◽  
E. Cortesi ◽  
N. M. Kalkhoran ◽  
J. M. Manke ◽  
B. L. Buchanan
Keyword(s):  
Leakage Current ◽  
Defect Density ◽  
Solid Phase ◽  
Substantial Reduction ◽  
Interface Region ◽  
Radiation Environment ◽  
Solid Phase Epitaxy ◽  
Defect Reduction ◽  
Radiation Induced

AbstractSubstantial reduction of defect density in silicon-on-sapphire (SOS) material is required to broaden its range of applications to include CMOS and bipolar devices. In recent years, solid phase epitaxy and regrowth (SPEAR) and double solid phase epitaxy (DSPE) processes were applied to SOS to reduce the density of defects in the silicon. These methods result in improved carrier mobilities, but also in increased leakage current, even before irradiation. In a radiation environment, this material has a large increase in radiation induced back channel leakage current as compared to standard wafers. In other words, the radiation hardness quality of the SOS declines when the crystalline quality of the Si near the sapphire interface is improved.In this paper, we will demonstrate that Ge implantation, rather than Si implantation normally employed in DSPE and SPEAR processes, is an efficient and more effective way to reduce the density of defects near the surface silicon region without improving the Si/sapphire interface region. Ge implantation may be used to engineer defects in the Si/sapphire interface region to eliminate back channel leakage problems.

scholarly journals Mechanism, Prevention, and Treatment of Radiation-Induced Salivary Gland Injury Related to Oxidative Stress

Antioxidants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1666
Author(s):  
Zijing Liu ◽  
Lihua Dong ◽  
Zhuangzhuang Zheng ◽  
Shiyu Liu ◽  
Shouliang Gong ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Head And Neck ◽  
Clinical Symptoms ◽  
Clinical Manifestations ◽  
Serious Adverse Event ◽  
Oral Infections ◽  
Normal Tissues ◽  
Radiation Induced ◽  
Swallowing Muscles

Radiation therapy is a common treatment for head and neck cancers. However, because of the presence of nerve structures (brain stem, spinal cord, and brachial plexus), salivary glands (SGs), mucous membranes, and swallowing muscles in the head and neck regions, radiotherapy inevitably causes damage to these normal tissues. Among them, SG injury is a serious adverse event, and its clinical manifestations include changes in taste, difficulty chewing and swallowing, oral infections, and dental caries. These clinical symptoms seriously reduce a patient’s quality of life. Therefore, it is important to clarify the mechanism of SG injury caused by radiotherapy. Although the mechanism of radiation-induced SG injury has not yet been determined, recent studies have shown that the mechanisms of calcium signaling, microvascular injury, cellular senescence, and apoptosis are closely related to oxidative stress. In this article, we review the mechanism by which radiotherapy causes oxidative stress and damages the SGs. In addition, we discuss effective methods to prevent and treat radiation-induced SG damage.

K-space filter effect in three-dimensional contrast MR angiography

1997 ◽  
Vol 38 (1) ◽  
pp. 173-175 ◽  
Author(s):  
K. Ito ◽  
J. Kato ◽  
S. Okada ◽  
T. Kumazaki
Keyword(s):  
Contrast Agent ◽  
Data Acquisition ◽  
Mr Angiography ◽  
Three Dimensional ◽  
Mr Images ◽  
Acquisition Period ◽  
Filter Effect ◽  
Flowing Material ◽  
Space Filter

Purpose: In three-dimensional (3-D) contrast MR angiography, temporal misregistration between the data acquisition period and the arrival of the contrast agent in the target vessels is thought to degrade the quality of the reconstructed images. The purpose of this study was to demonstrate and investigate this effect in phantom experiments. Material and Methods: MR images of a phantom tube were evaluated with flowing materials of water or Gd-DTPA solution by changing from water to Gd-DTPA solution halfway through the data acquisition period. Results: While no signal could be acquired with a stream of water in the tube, a clear signal was obtained with a flow of Gd-DTPA solution. Blurring and ghost artifacts surrounding the tube along the phase-encoding direction were observed when the flowing material was changed from water to Gd-DTPA solution halfway through the data acquisition period. Conclusion: K-space filter effect occurs during 3-D contrast MR angiography owing to the transient passage of the contrast agent, and this effect causes spatial artifacts in the reconstructed images.

Premedications for Cancer Therapies: A Primer for the Hematology/Oncology Provider

2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Amber Clemmons, PharmD, BCOP ◽  
Arpita Gandhi, PharmD, BCOP ◽  
Andrea Clarke, PharmD ◽  
Sarah Jimenez, APN-BC, AGACNP, AOCNP ◽  
Thuy Le, MD ◽  
...  
Keyword(s):  
Best Practices ◽  
Adverse Events ◽  
Chemotherapeutic Agents ◽  
Patient Specific ◽  
Cancer Therapies ◽  
Quality Of Data ◽  
Advanced Practitioner ◽  
Patients At Risk ◽  
Radiation Induced

Chemotherapeutic agents and radiation therapy are associated with numerous potential adverse events (AEs). Many of these common AEs, namely chemotherapy- or radiation-induced nausea and vomiting, hypersensitivity reactions, and edema, can lead to deleterious outcomes (such as treatment nonadherence or cessation, or poor clinical outcomes) if not prevented appropriately. The occurrence and severity of these AEs can be prevented with the correct prescribing of prophylactic medications, often called “premedications.” The advanced practitioner in hematology/oncology should have a good understanding of which chemotherapeutic agents are known to place patients at risk for these adverse events as well as be able to determine appropriate prophylactic medications to employ in the prevention of these adverse events. While several guidelines and literature exist regarding best practices for prophylaxis strategies, differences among guidelines and quality of data should be explored in order to accurately implement patient-specific recommendations. Herein, we review the existing literature for prophylaxis and summarize best practices.

scholarly journals Interobserver variability in quality assessment of magnetic resonance images

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Rafal Obuchowicz ◽  
Mariusz Oszust ◽  
Adam Piorkowski
Keyword(s):  
Magnetic Resonance ◽  
Image Quality ◽  
Quality Assessment ◽  
Image Quality Assessment ◽  
Interobserver Variability ◽  
Poor Performance ◽  
Magnetic Resonance Images ◽  
Perceptual Quality ◽  
Mr Images

Abstract Background The perceptual quality of magnetic resonance (MR) images influences diagnosis and may compromise the treatment. The purpose of this study was to evaluate how the image quality changes influence the interobserver variability of their assessment. Methods For the variability evaluation, a dataset containing distorted MRI images was prepared and then assessed by 31 experienced medical professionals (radiologists). Differences between observers were analyzed using the Fleiss’ kappa. However, since the kappa evaluates the agreement among radiologists taking into account aggregated decisions, a typically employed criterion of the image quality assessment (IQA) performance was used to provide a more thorough analysis. The IQA performance of radiologists was evaluated by comparing the Spearman correlation coefficients, ρ, between individual scores with the mean opinion scores (MOS) composed of the subjective opinions of the remaining professionals. Results The experiments show that there is a significant agreement among radiologists (κ=0.12; 95% confidence interval [CI]: 0.118, 0.121; P<0.001) on the quality of the assessed images. The resulted κ is strongly affected by the subjectivity of the assigned scores, separately presenting close scores. Therefore, the ρ was used to identify poor performance cases and to confirm the consistency of the majority of collected scores (ρmean = 0.5706). The results for interns (ρmean = 0.6868) supports the finding that the quality assessment of MR images can be successfully taught. Conclusions The agreement observed among radiologists from different imaging centers confirms the subjectivity of the perception of MR images. It was shown that the image content and severity of distortions affect the IQA. Furthermore, the study highlights the importance of the psychosomatic condition of the observers and their attitude.

Effect of residual charge on formation of radiation-induced current in a compton detector

1983 ◽  
Vol 54 (5) ◽  
pp. 366-369
Author(s):  
A. P. Elokhin ◽  
N. I. Filatov ◽  
S. N. Makeev
Keyword(s):  
Induced Current ◽  
Residual Charge ◽  
Radiation Induced

P3.99. Dose related radiation-induced mucositis in oral andoropharyngeal cancer and its impact on quality of life

2009 ◽  
Vol 3 (1) ◽  
pp. 233-234
Author(s):  
J. Bardy ◽  
N.J. Slevin ◽  
K. Mais ◽  
D. Ryder ◽  
A. Molassiotis
Keyword(s):  
Quality Of Life ◽  
Radiation Induced

Texture analysis of T1-w and T2-w MR images allows a quantitative evaluation of radiation-induced changes of internal obturator muscles after radiotherapy for prostate cancer

2018 ◽  
Vol 45 (4) ◽  
pp. 1518-1528 ◽  
Author(s):  
Elisa Scalco ◽  
Tiziana Rancati ◽  
Ileana Pirovano ◽  
Alfonso Mastropietro ◽  
Federica Palorini ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Texture Analysis ◽  
Quantitative Evaluation ◽  
Mr Images ◽  
Radiation Induced ◽  
Induced Changes
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