Polymer Photodetectors for Printable, Flexible, and Fully Tissue Equivalent X‐Ray Detection with Zero‐Bias Operation and Ultrafast Temporal Responses

2021 ◽  
pp. 2001298
Author(s):  
Jessie A. Posar ◽  
Jeremy Davis ◽  
Saree Alnaghy ◽  
Dean Wilkinson ◽  
Sophie Cottam ◽  
...  
Keyword(s):  
Zero Bias ◽  
X Ray ◽  
Tissue Equivalent

scholarly journals Influence of Different Percentages of Binders on the Physico-Mechanical Properties of Rhizophora spp. Particleboard as Natural-Based Tissue-Equivalent Phantom for Radiation Dosimetry Applications

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1868
Author(s):  
Siti Hajar Zuber ◽  
Nurul Ab. Aziz Hashikin ◽  
Mohd Fahmi Mohd Yusof ◽  
Mohd Zahri Abdul Aziz ◽  
Rokiah Hashim
Keyword(s):  
Mechanical Properties ◽  
Radiation Dosimetry ◽  
Structural Integrity ◽  
Soy Flour ◽  
Lower Percentage ◽  
Internal Bonding ◽  
X Ray ◽  
Tissue Equivalent ◽  
Tissue Equivalent Phantom ◽  
Edx Analyses

Rhizophora spp. particleboard with the incorporation of lignin and soy flour as binders were fabricated and the influence of different percentages of lignin and soy flour (0%, 6% and 12%) on the physico-mechanical properties of the particleboard were studied. The samples were characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray fluorescence (XRF) and internal bonding. The results stipulated that the addition of binders in the fabrication of the particleboard did not change the functional groups according to the FTIR spectrum. For XRD, addition of binders did not reveal any major transformation within the composites. SEM and EDX analyses for all percentages of binders added showed no apparent disparity; however, it is important to note that the incorporation of binders allows better bonding between the molecules. In XRF analysis, lower percentage of chlorine in the adhesive-bonded samples may be advantageous in maintaining the natural properties of the particleboard. In internal bonding, increased internal bond strength in samples with binders may indicate better structural integrity and physico-mechanical strength. In conclusion, the incorporation of lignin and soy flour as binders may potentially strengthen and fortify the particleboard, thus, can be a reliable phantom in radiation dosimetry applications.

scholarly journals Evaluation of scatter suppression algorithm for X-ray exposure of soft tissue equivalent phantoms over nominal energy range using FLUKA code

2021 ◽  
Vol 47 (2) ◽  
pp. 779-789
Author(s):  
Samson O Omondi ◽  
Innocent J Lugendo ◽  
Ramadhan R Kazema ◽  
Robert Kinyua
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Soft Tissue ◽  
Energy Range ◽  
Scatter Correction ◽  
Tissue Imaging ◽  
Diagnostic Image Quality ◽  
Cross Sectional ◽  
X Ray ◽  
Tissue Equivalent

Soft tissue imaging is heavily impaired by streaks and cupping effects associated with X-ray scatter. Quality of images from projection imaging may be improved by the use of enhanced anti-scatter grids’ designs with potency to reject significant scatter. However, optimization of grid characteristics requires investigation to improve diagnostic image quality. Transmitted scatter spatially distributed degrades images engendering need for effective scatter correction protocols. This study investigated the pre-scan scatter suppression algorithm for X-ray exposure of soft tissue equivalent phantoms over nominal energy range. Adipose tissue and polymethyl methacrylate phantoms of cross-sectional area (30 x 30) cm2 and of varying thickness from 2 to 8 cm in 1 cm increments were successively exposed using energy ranging between 20–50 kVp. Monte Carlo simulation based on FLUKA code and flair interface was used to generate an input file for execution. The source simulated five cycles of ten million photons each of annular X-ray photon beam of radius, r = 0.5 cm at fixed field of view (FOV) through anti-scatter grid on to gadolinium oxysulfide detector. The transmitted total, scatter and primary estimates were evaluated with and without grids over varying phantom thicknesses, energy and grid design features. The simulated and experimental results obtained were comparable and in agreement with previous literature. Pearson’s correlation coefficients for scatter fraction and scatter to primary ratio were 0.983 and 0.981, respectively. The strong correlation between simulation and experiment results indicated correctness in methodology and protocol. The algorithms and protocols in the simulation would be appropriate for designing grids with enhanced scatter rejection capabilities. Keywords: FLUKA code, Monte Carlo simulation, Scatter suppression algorithm, Scatter correction, X-ray imaging systems.  

X-ray spectrometry applied for determination of linear attenuation coefficient of tissue-equivalent materials

2019 ◽  
Vol 160 ◽  
pp. 89-95 ◽  
Author(s):  
Audrew Frimaio ◽  
Bruna C. Nascimento ◽  
Ramon M.M. Barrio ◽  
Leticia L. Campos ◽  
Paulo R. Costa
Keyword(s):  
Attenuation Coefficient ◽  
Linear Attenuation Coefficient ◽  
X Ray ◽  
Tissue Equivalent

scholarly journals Evaluation of stray radiation to the operator for five hand-held dental X-ray devices

2019 ◽  
Vol 48 (5) ◽  
pp. 20180301 ◽  
Author(s):  
Richard Smith ◽  
Richard Tremblay ◽  
Graeme M Wardlaw
Keyword(s):  
Digital Image ◽  
Protected Area ◽  
Ionization Chamber ◽  
Portable Devices ◽  
X Ray ◽  
Air Kerma ◽  
Tissue Equivalent ◽  
Stray Radiation ◽  
The Mean ◽  
Occupational Radiation

Objectives: Evaluate stray radiation to the operator, as represented by a plane within the significant zone of occupancy (SZO), produced by five models of hand-held intraoral dental X-ray devices (HIDXDs). Methods: The stray radiation for five models of HIDXDs was measured, using an anthropomorphic tissue-equivalent head phantom as a scattering object. An ionization chamber was used to measure the air kerma (μGy) at 63 positions in a 160 cm high by 60 cm wide plane that was 10 cm behind the X-ray device, identified as being within the SZO. Results: Based on the measured air kerma from stray radiation of five different HIDXDs, the estimated annual air kerma at all measured spatial positions was calculated. When calculated using a median air kerma of 0.8 mGy at the distal end of the cone, as typically required for digital image receptors, 1 the ranges for estimated annual air kerma in the SZO across the devices were 0.14–0.77 mGy for the median, 0.41–1.01 mGy for the mean, and 1.32–2.55 mGy for the maximum. Similarly, when calculated using a median air kerma of 1.6 mGy as typically required for D-speed film, 2 the ranges for estimated annual air kerma across the devices were 0.28–1.54 mGy for the median, 0.83–2.03 mGy for the mean, and 2.64–5.10 mGy for the maximum. Conclusions: From measured air kerma values of stray radiation in the SZO, estimated annual exposures to the operator for HIDXDs are expected to be greater than from conventional wall-mounted or portable devices activated from a protected area (at a distance or behind shielding). HIDXDs should therefore only be used when patient accessibility makes their use necessary and the use of a portable device on a stand or a wall-mounted device is not reasonably feasible. This approach would keep occupational radiation exposures of dental workers as low as reasonably achievable.

scholarly journals Enhanced Photocurrent of the Ag Interfaced Topological Insulator Bi2Se3 under UV- and Visible-Light Radiations

Nanomaterials ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3353
Author(s):  
Chih-Chiang Wang ◽  
Pao-Tai Lin ◽  
Fuh-Sheng Shieu ◽  
Han-Chang Shih
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Photoelectron Spectroscopy ◽  
Uv Light ◽  
Visible Range ◽  
Zero Bias ◽  
X Ray ◽  
Topological Quantum ◽  
Conductive Surface ◽  
Narrow Bandgap

Bi2Se3 is a topological quantum material that is used in photodetectors, owing to its narrow bandgap, conductive surface, and insulating bulk. In this work, Ag@Bi2Se3 nanoplatelets were synthesized on Al2O3(100) substrates in a two-step process of thermal evaporation and magnetron sputtering. X-ray diffractometer (XRD), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) revealed that all samples had the typical rhombohedral Bi2Se3. Field-emission scanning electron microscopy (FESEM)-energy dispersive x-ray spectroscopy (EDS), XPS, and HRTEM confirmed the presence of the precipitated Ag. The optical absorptance of Bi2Se3 nanoplatelets in UV-visible range decreased with the Ag contents. Results of photocurrent measurements under zero-bias conditions revealed that the deposited Ag affected photosensitivity. A total of 7.1 at.% Ag was associated with approximately 4.25 and 4.57 times higher photocurrents under UV and visible light, respectively, than 0 at.% Ag. The photocurrent in Bi2Se3 at 7.1 at.% Ag under visible light was 1.72-folds of that under UV light. This enhanced photocurrent is attributable to the narrow bandgap (~0.35 eV) of Bi2Se3 nanoplatelets, the Schottky field at the interface between Ag and Bi2Se3, the surface plasmon resonance that is caused by Ag, and the highly conductive surface that is formed from Ag and Bi2Se3. This work suggests that the appropriate Ag deposition enhances the photocurrent in, and increases the photosensitivity of, Bi2Se3 nanoplatelets under UV and visible light.

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