scholarly journals Comparison of gross tumor volumes of pulmonary metastasis defined by CT and MRI in 0.345 T MRI-guided radiotherapy

BJR|Open ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 20200010
Author(s):  
Yukihiro Hama ◽  
Etsuko Tate
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Correlation Coefficient ◽  
Magnetic Field Strength ◽  
Clinical Report ◽  
Significant Difference ◽  
Mri Guided ◽  
The Difference ◽  
Low Magnetic Field ◽  
Ct And Mri

Objective: To assess the difference in gross tumor volumes (GTVs) defined by CT (GTV-CT) and by low magnetic field strength (0.345 T) MRI (GTV-MRI) in patients simulated for MRI-guided radiotherapy forlung metastasis. Methods: 28 patients (148 lesions) who underwent CT and MRI simulation with the tri-60Co MRI-guided radiotherapy system (MRIdian, ViewRay) were included in this study. GTV-CT and GTV-MRI were compared using the paired t-test. The equivalence of variance between GTV-CT and GTV-MRI of small lesions (GTV-CT <1 ml) and large ones (GTV-CT >= 1 ml) was evaluated using F-test. The correlation between GTV-CT and GTV-MRI was evaluated by the correlation coefficient. Results: GTV-MRI was 120% larger than GTV-CT (p < 0.001) for small lesions, whereas GTV-MRI was 40% larger than GTV-CT (p < 0.001) for large lesions. In small lesions, the variation in GTV-MRI was significantly larger than that of GTV-CT (p < 0.001). There was no significant difference in the variation of GTV-MRI and GTV-CT in large lesions (p = 0.121). The correlation coefficient for small lesions was 0.93, whereas that for large lesions was 0.99, with large lesions having better correlation. Conclusions: GTV-MRI was larger than GTV-CT and the correlation between GTV-MRI and GTV-CT was better in large lesions. If the tumor volume is 1 ml or larger, the lesion can be accurately monitored even with a low magnetic field strength MRI. Advances in knowledge: This study is the first clinical report to evaluate the tolerability of MRI images in 0.345 T MRI-guided radiotherapy for lung metastasis. GTV contoured by MRI was larger than GTV by CT, and this tendency was more pronounced in small tumors of less than 1 ml.

scholarly journals ERROR IN MEASURING THE MAGNETIC LIQUID MAGNETIZATION BY THE NUCLEAR MAGNETIC RESONANCE, CAUSED BY THE UNCERTAINTY OF THE EFFECTIVE FIELD CONSTANT

2021 ◽  
Vol 57 ◽  
pp. 15-18
Author(s):  
Alexander I. Zhernovoy ◽  
◽  
Ilya A. Yakimenko ◽  
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Effective Field ◽  
Magnetic Liquid ◽  
Different Shapes ◽  
The Difference ◽  
The Magnetic Field

The magnetic liquid magnetization is usually determined by measuring the magnetic field strength, which linearly depends on the effective field constant of the liquid and the demagnetization coefficient of the sample. The article proposes to measure the magnetic field strength, generated by the same magnetic liquid in the samples of different shapes, and to determine the magnetization relying on the difference in strength, generated by the samples of various shapes, taking advantage of the fact that the effective field constant does not depend on the shape of the sample

scholarly journals Stretching of the Super-Elastic Double-Helix Geon. Wheeler´s Thermal Geons as Quanta of Heat and Momentum. Bohm´s Diffusion and the Heating of the Solar Corona and Heating of the Earth - Geon Engineering. Milgrom-Verlinde Constant. Mareš - Šesták constant

2020 ◽  
Vol 12 (2) ◽  
pp. 12
Author(s):  
Jiri Stavek
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Solar Corona ◽  
Magnetic Field Strength ◽  
Double Helix ◽  
David Bohm ◽  
The Earth ◽  
Highly Sensitive ◽  
Low Magnetic Field ◽  
The Magnetic Field

In our approach we have combined knowledge of Old Masters (working in this field before the year 1905), New Masters (working in this field after the year 1905) and Dissidents under the guidance of Louis de Broglie and David Bohm. Based on the great works of Julian Schwinger and John Archibald Wheeler we will study properties of geons formed by fusion of two soft x-ray particles (dyons) in the Schwarzschild gravitation core in our Sun at temperature 16 * 106 K. There are now several Teams that are able to achieve this fusion temperature in their special instruments (Tokamak, HL-2M Tokamak, Wendelstein 7-X, NIF, etc.) and to study properties of those formed geons. Thermal geons are with us all the time but they are very deeply hidden in our experiments. We have newly introduced Mareš - Šesták constant as the ratio of geon momentum to heat quantum of geon. The key information to enter into the World of geons was the empirical formula of David Bohm - the very well-known Bohm diffusion. From this formula we have extracted the amplitude, wavelength, frequency, quantum of the geon action, displacement law for geons, etc. It was found that geons are highly sensitive to the magnetic field strength. At a low magnetic field strength, the “inflation of geons” can occur. This effect could explain the Superheating of the Solar corona and the observed Heating of the Earth during two last centuries influenced by the changes in the Earth´s magnetic field. Geon engineering might modify the geon volume through the magnetic field strength. On the other hand, we were stimulated by the works of Mordehai Milgrom and Eric Verlinde and derived the Milgrom-Verlinde constant describing the gravitational field strength leading to the Newtonian gravitational constant on thermodynamic principles. The quantum of the geon momentum might open a new way how to understand gravitational phenomena. Can it be that Nature cleverly inserted geons into our experimental apparatuses and into our very-well known Old Formulae? We want to pass this concept into the hands of Readers of this Journal better educated in the Mathematics, Physics, and Thermodynamics.

Study on Test about the Impermeability of Magnetic Water Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 601-604 ◽  
Author(s):  
Yi Xin Wang ◽  
Xuan Wang ◽  
You Kai Wang
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Flow Speed ◽  
Magnetized Water ◽  
Test Parameters ◽  
The Difference ◽  
The Magnetic Field ◽  
Cross Test ◽  
Magnetic Water

The compactness and water impermeability of the concrete mixed with magnetized water in different degrees are studied in the thesis. According to the principle of cross-test, 21 samples with the intensity levels C20, C25 and C30 are chosen in the impermeability test. The test indicates the difference of impermeability between magnetized water concrete and ordinary water concrete at the condition of same strength to study the special law influenced by the flow speed of water and the magnetic field strength. The best magnetic field strength and the best water flow speed have been obtained among the range of test parameters.

Prevalence and MRI findings of incidentally detected pituitary non-enhancing lesion on brain MRI in children

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hae Won Yoo ◽  
Jeong Rye Kim ◽  
Jee Suk Yu
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Signal Intensity ◽  
Pediatric Patients ◽  
Brain Mri ◽  
Slice Thickness ◽  
Mri Findings ◽  
Contrast Enhanced ◽  
Significant Difference

Abstract Objectives To determine the prevalence and MRI findings of incidentally detected pituitary nonenhancing lesion on brain MRI in children, and to compare the detection rates of pituitary nonenhancing lesion according to magnetic field strength and acquisition technique. Methods Pediatric patients (≤18 years old) who underwent brain MRI with contrast-enhancement between January 2018 and September 2019 were retrospectively included (n=365). The presence, size, and signal intensity of pituitary nonenhancing lesions were assessed by two radiologists. The prevalence of pituitary nonenhancing lesions was compared between different magnetic field strengths and MRI acquisition techniques. Results Pituitary nonenhancing lesions were identified in 76 patients (20.8%). The anteroposterior diameter of pituitary nonenhancing lesion was the smallest diameter in most patients (93.4%; mean diameter ± SD of 2.4 ± 1.5 mm; range: 0.9–9.0 mm). Sixty-seven percent of the pituitary nonenhancing lesions were hypointense on T1-weighted imaging, 44.1% were hyperintense on T2-weighted imaging, and 12.9% showed low signal intensity on susceptibility-weighted imaging. There was no diffusion restriction in any of the nonenhancing lesions. There was no significant difference in the prevalence of pituitary nonenhancing lesions according to magnetic field strength, age, gender, slice thickness, or 2D vs. 3D contrast-enhanced T1-weighted imaging sequence. Conclusions Pituitary nonenhancing lesions were identified on contrast-enhanced brain MRI in 20.8% of pediatric patients, with no significant difference in the prevalence according to magnetic field strength, slice thickness, and 2D or 3D contrast-enhanced T1-weighted imaging.

Assessment of Natural and Climatic Factors (the Earth’s Magnetic Field) in Selected Territories: Report 1

2021 ◽  
pp. 16-22
Author(s):  
SN Noskov ◽  
EG Golovina ◽  
OM Stupishina ◽  
GB Yeremin ◽  
NN Krutikova
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Climatic Factors ◽  
Local Population ◽  
Climatic Conditions ◽  
Monitoring Methods ◽  
Earth’S Magnetic Field ◽  
Significant Difference ◽  
Earth's Magnetic Field

Background: A man is constantly exposed to numerous environmental factors, including meteorological conditions of the earth and space weather. The study of human health effects of these factors is of increasing interest both for science and practice. Objective: To compare instrumental and computational methods for assessing the Earth’s magnetic field in selected territories for further identification of priority natural and climatic factors and development of region-specific measures for adaptation of the local population to climate change, which should be taken into account when conducting social and hygienic monitoring. Methods: Instrumental measurements of the Earth’s magnetic field strength were carried out on the territories of the Moscow, Voronezh, Rostov, and Krasnodar regions of the Russian Federation, in August 2020. The total number of measurements was at least 15 at each point. The studies were conducted in accordance with the existing approved standard. Results and discussion: The territories for the study were selected taking into account changes in the latitude of the area, which has a priority importance in the formation of natural and climatic conditions of these regions. During the research, it was found that there was no significant difference in the values of the Earth’s magnetic field strength during the day and at night, which is associated with the main error of the device (MTM-01 three-component magnetometer). The obtained instrumental values of the magnetic field strength index ranged from 37.1 to 40.51 A/m. When analyzing the results obtained, there is a tendency to increase the intensity of the Earth’s magnetic field in the direction from South to North (Krasnodar Territory, Rostov, Voronezh, Moscow regions). The range of calculated values of the intensity indicator was from 39.9 to 42.19 A/m. The obtained instrumental data correlate with the calculated values of the Earth’s magnetic field. Conclusions: We conducted instrumental studies complying with existing models for estimating the Earth’s magnetic field strength, thus enabling application of our estimates in scientific research.

scholarly journals Models for the Formation of Binary and Millisecond Pulsars

1996 ◽  
Vol 165 ◽  
pp. 243-256
Author(s):  
D. Bhattacharya
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
List Type ◽  
Radio Pulsars ◽  
Millisecond Pulsars ◽  
Spin Period ◽  
Low Magnetic Field

Under the name “binary and millisecond pulsars” are grouped a number of radio pulsars, forming roughly 10% of the known pulsar population, which distinguish themselves on three counts: — Short spin period— Low magnetic-field strength— Presence of an evolved binary companion

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