scholarly journals Predicting fringe visibility in dual-phase grating interferometry with polychromatic X-ray sources

2020 ◽  
Vol 28 (6) ◽  
pp. 1055-1067
Author(s):  
Aimin Yan ◽  
Xizeng Wu ◽  
Hong Liu
Keyword(s):  
Radiation Dose ◽  
Numerical Simulations ◽  
Design Optimization ◽  
Phase Modulation ◽  
Dual Phase ◽  
X Rays ◽  
Fringe Visibility ◽  
Phase Grating ◽  
X Ray ◽  
Quantitative Theory

Dual phase grating X-ray interferometry is radiation dose-efficient as compared to common Talbot-Lau grating interferometry. The authors developed a general quantitative theory to predict the fringe visibility in dual-phase grating X-ray interferometry with polychromatic X-ray sources. The derived formulas are applicable to setups with phase gratings of any phase modulation and with either monochromatic or polychromatic X-rays. Numerical simulations are presented to validate the derived formulas. The theory provides useful tools for design optimization of dual-phase grating X-ray interferometers.

Analysis of period and visibility of dual phase grating interferometer

2021 ◽  
Author(s):  
Jun Yang ◽  
Jian-Heng Huang ◽  
Yao-Hu Lei ◽  
Jing-Biao Zheng ◽  
Yu-Zheng Shan ◽  
...  
Keyword(s):  
Theoretical Method ◽  
Field Of View ◽  
Large Field ◽  
Dual Phase ◽  
Fringe Visibility ◽  
Phase Grating ◽  
X Ray ◽  
Dose Efficiency ◽  
Grating Interferometer ◽  
Theoretical Results

Abstract Dual phase grating interferometer may simultaneously achieve large field of view and high X-ray dose efficiency. In this paper, we developed a simple theoretical method to better understand the imaging process of the dual phase grating interferometer. The derivation process of fringe period and the optimal visibility conditions of the dual phase grating interferometer were shown in detail. Then, we theoretically proved that the fringe period and optimal visibility conditions of the dual phase grating interferometer included that of the Talbot interferometer. By comparing our experimental results with those of other researchers, we found that when the positions of phase gratings were far away from the positions where the fringe visibility was optimal, the fringe period of the dual π-phase grating interferometer was twice longer than the theoretical results under the illumination of polychromatic X-ray. And this conclusion may explain the contradictory research results of dual phase grating interferometer among different researchers.

scholarly journals Optimization of X-ray Investigations in Dentistry Using Optical Coherence Tomography

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4554
Author(s):  
Ralph-Alexandru Erdelyi ◽  
Virgil-Florin Duma ◽  
Cosmin Sinescu ◽  
George Mihai Dobre ◽  
Adrian Bradu ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Radiation Dose ◽  
Imaging Techniques ◽  
Image Resolution ◽  
Optical Coherence ◽  
X Rays ◽  
High Quality ◽  
X Ray

The most common imaging technique for dental diagnoses and treatment monitoring is X-ray imaging, which evolved from the first intraoral radiographs to high-quality three-dimensional (3D) Cone Beam Computed Tomography (CBCT). Other imaging techniques have shown potential, such as Optical Coherence Tomography (OCT). We have recently reported on the boundaries of these two types of techniques, regarding. the dental fields where each one is more appropriate or where they should be both used. The aim of the present study is to explore the unique capabilities of the OCT technique to optimize X-ray units imaging (i.e., in terms of image resolution, radiation dose, or contrast). Two types of commercially available and widely used X-ray units are considered. To adjust their parameters, a protocol is developed to employ OCT images of dental conditions that are documented on high (i.e., less than 10 μm) resolution OCT images (both B-scans/cross sections and 3D reconstructions) but are hardly identified on the 200 to 75 μm resolution panoramic or CBCT radiographs. The optimized calibration of the X-ray unit includes choosing appropriate values for the anode voltage and current intensity of the X-ray tube, as well as the patient’s positioning, in order to reach the highest possible X-rays resolution at a radiation dose that is safe for the patient. The optimization protocol is developed in vitro on OCT images of extracted teeth and is further applied in vivo for each type of dental investigation. Optimized radiographic results are compared with un-optimized previously performed radiographs. Also, we show that OCT can permit a rigorous comparison between two (types of) X-ray units. In conclusion, high-quality dental images are possible using low radiation doses if an optimized protocol, developed using OCT, is applied for each type of dental investigation. Also, there are situations when the X-ray technology has drawbacks for dental diagnosis or treatment assessment. In such situations, OCT proves capable to provide qualitative images.

scholarly journals Sample phase gradient and fringe phase shift in dual phase grating X-ray interferometry

2019 ◽  
Vol 27 (24) ◽  
pp. 35437 ◽  
Author(s):  
Aimin Yan ◽  
Xizeng Wu ◽  
Hong Liu
Keyword(s):  
Phase Shift ◽  
Dual Phase ◽  
Phase Grating ◽  
Phase Gradient ◽  
X Ray

Interaction of ionizing radiations with matter

2015 ◽  
Author(s):  
Colin J Martin
Keyword(s):  
Radiation Dose ◽  
Scattered Radiation ◽  
Final Section ◽  
Radioactive Decay ◽  
Photoelectric Effect ◽  
X Rays ◽  
X Ray ◽  
Radiation Fields ◽  
Ionizing Radiations ◽  
Radiology Image

Interactions of ionizing radiations with matter are fundamental to the practice of radiation protection. They determine the magnitude and distribution of doses in tissues, the performance of detectors and imaging devices, and the attenuating properties of shielding materials. This chapter describes briefly the processes of radioactive decay and the properties of the various particles emitted, and then goes on to consider the interactions of radiation with matter. Electron interactions with metals result in bremsstrahlung and characteristic X-rays that form the basis of X-ray production. The interaction mechanisms of X-rays with tissue, particularly the photoelectric effect and Compton scattering, are inherent in the process of radiology image formation. Understanding the physics behind X-ray interactions so that scattered radiation can be taken into account is crucial in designing methods for accurately measuring radiation dose parameters. The final section deals with the dose related variables involved in measurement of radiation fields.

scholarly journals UJI KELAYAKAN PESAWAT SINAR-X TERHADAP PROYEKSI PA (POSTERO-ANTERIOR) DAN LAT (LATERAL) PADA TEKNIK PEMERIKSAAN FOTO THORAX

2017 ◽  
Vol 18 (1) ◽  
pp. 27
Author(s):  
Kadek Miniati ◽  
Gusti Ngurah Sutapa ◽  
I Wayan Balik Sudarsana
Keyword(s):  
Radiation Dose ◽  
X Rays ◽  
Tube Voltage ◽  
Limit Values ◽  
X Ray ◽  
Limit Value ◽  
Irradiation Field ◽  
Interval Distance ◽  
Dosage Guidelines ◽  
Feasibility Test

Research has been conducted to determine feasibility test of the X-ray planePA and LAT projections on chest x-ray techniques. The study using a water phantom object as a substitute for patients with variations in interval distance ofthe  100-180 cm. Measurement of radiation dose X-rays performed five repetitions , measurable doses had be read on the device electrometer. Exposition factors to the PA projection using a tube voltage of 75 kV, current and time of 3,2 mAs, the irradiation field areaof (30 x 30) cm2.For the LAT projection tube voltage of 80 kV, current and time of 6,3 mAs, and the irradiation field area of (20 x 30) cm2. It the study of the radiation dose X-ray plane projection PA and LAT is optimal is below the limit value at the level of dosage guidelines BAPETEN No 08 of 2011. Obtained PA projections are below the value of 0,4 mGy while LAT projection is below the value of 1,5 mGy. The radiation dose X-rays plane using a variation of 100-180 cm distance is still below the dose limit values ??, thus meeting the objectives anssurance quality and quality control.

Characterization of the Theorectical Radiation Dose Enhancement from Nanoparticles

2007 ◽  
Vol 6 (5) ◽  
pp. 395-401 ◽  
Author(s):  
John C. Roeske ◽  
Luis Nuñez ◽  
Mark Hoggarth ◽  
Edwardine Labay ◽  
Ralph R. Weichselbaum
Keyword(s):  
Radiation Dose ◽  
Enhancement Factor ◽  
Low Energy ◽  
External Beam ◽  
X Rays ◽  
Nanoparticle Concentration ◽  
Dose Enhancement ◽  
X Ray ◽  
Delivered Dose

Recently, nanoparticles have been considered as a method of providing radiation dose enhancement in tumors. In order to quantify this affect, a dose enhancement factor (DEF) is defined that represents the ratio of the dose deposited in tumor with nanoparticles, divided by the dose deposited in the tumor without nanoparticles. Materials with atomic numbers (Z) ranging from 25 to 90 are considered in this analysis. In addition, the energy spectrum for a number of external beam x-ray sources and common radionuclides are evaluated. For a nanoparticle concentration of 5 mg/ml, the DEF is < 1.05 for Co-60, Ir-192, Au-198, Cs-137, 6, 18, and 25 MV x-rays for all materials considered. However, relatively large increases in the DEF are observed for 50, 80, 100, and 140 KVp x-rays as well as Pd-103 and I-125. The DEF increases for all sources as Z varies from 25–35. From Z = 40–60, the DEF plateaus or slightly decreases. For higher Z materials (Z>70), the DEF increases and is a maximum for the highest Z materials. High atomic number nanoparticles coupled with low energy external beam x-rays or brachytherapy sources offer the potential of significantly enhancing the delivered dose.

WHY MEASUREMENT OF RADIATION DOSE BY MEDICAL PHYSICIST AND RADIATION ONCOLOGIST BOTH?

2021 ◽  
pp. 219-222
Author(s):  
Rubina Rubina ◽  
Baig M.Q ◽  
Kumar Dev
Keyword(s):  
Radiation Dose ◽  
Gamma Rays ◽  
Biological Effect ◽  
Radiation Energy ◽  
The Body ◽  
X Rays ◽  
Radiation Oncologist ◽  
X Ray ◽  
Γ Rays ◽  
Different Tissues

Many years after the discovery of X-ray's and gamma rays. They have been used empirically in medicine, later on realized that this approach was dangerous mainly in radiotherapy and up to some extent in diagnostic radiology. Thus Means of measuring x-ray/γ-rays had to be found in terms of unit of x-rays quantity dened and accepted. The magnitude of the biological effect desirable in case therapy and undesirable in case of diagnosis. It depends upon how much radiation energy is absorbed by irradiated material. X-ray dosimetry is the measurement of energy absorbed in any material particularly in different tissues of the body.

X-ray diffraction by phase diffraction gratings

2015 ◽  
Vol 48 (4) ◽  
pp. 1159-1164 ◽  
Author(s):  
D. V. Irzhak ◽  
M. A. Knyasev ◽  
V. I. Punegov ◽  
D. V. Roshchupkin
Keyword(s):  
Phase Shift ◽  
Diffraction Pattern ◽  
Diffraction Grating ◽  
Diffraction Gratings ◽  
X Rays ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Phase Grating ◽  
X Ray ◽  
Phase Diffraction Grating

The diffraction properties of phase gratings with the periodD= 1.6, 1.0 and 0.5 µm fabricated on an Si(111) crystal by e-beam lithography were studied by triple-axis X-ray diffraction. A 100 nm-thick tungsten layer was used as a phase-shift layer. It is shown that the presence of a grating as a phase-shift W layer on the surface of the Si(111) crystal causes the formation of a complicated two-dimensional diffraction pattern related to the diffraction of X-rays on the phase grating at the X-ray entrance and exit from the crystal. A model of X-ray diffraction on the W phase diffraction grating is proposed.

scholarly journals Generation, characterization, and medical utilization of laser-produced emission continua

2000 ◽  
Vol 18 (3) ◽  
pp. 563-570 ◽  
Author(s):  
S. SVANBERG ◽  
S. ANDERSSON-ENGELS ◽  
R. CUBEDDU ◽  
E. FÖRSTER ◽  
M. GRÄTZ ◽  
...  
Keyword(s):  
Phase Modulation ◽  
Biomedical Applications ◽  
Laser System ◽  
Laser Pulses ◽  
Medical Utilization ◽  
X Rays ◽  
Visible Radiation ◽  
X Ray ◽  
Optical Mammography ◽  
Terawatt Laser

Intense continua of electromagnetic radiation of very brief duration are formed in the interaction of focused ultra-short terawatt laser pulses with matter. Two different kinds of experiments, which have been performed utilizing the Lund 10 Hz titanium-doped sapphire terawatt laser system are being described, where visible radiation and X-rays, respectively, have been generated. Focusing into water leads to the generation of a light continuum through self-phase modulation. The propagation of the light through tissue was studied addressing questions related to optical mammography and specific chromophore absorption. When terawatt laser pulses are focused onto a solid target with high nuclear charge Z, intense X-ray radiation of few ps duration and with energies exceeding hundreds of keV is emitted. Biomedical applications of this radiation are described, including differential absorption and gated-viewing imaging.

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