Performance evaluation of lead-monoxide dosimeter with parylene coating for quality assurance of brachytherapy devices

2021 ◽  
Vol 16 (11) ◽  
pp. P11017
Author(s):  
S.W. Yang ◽  
M.J. Han ◽  
J.H. Jung ◽  
C.W Mun ◽  
H.L. Cho ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Performance Improvement ◽  
Angular Dependence ◽  
Electromagnetic Waves ◽  
High Probability ◽  
Signal Stability ◽  
Naked Eye ◽  
Lead Monoxide ◽  
Interval Distance ◽  
The Difference

Abstract The source position of irradiation is identified using a method that uses rulers and films for quality assurance (QA) in brachytherapy. However, this method involves a high probability of errors, because the scales are checked using the naked eye, and QA is indirectly performed using photographs. Lead monoxide (PbO) is widely used as a semiconductor dosimeter, because it is a photoconductor that generates electrons in response to electromagnetic waves. Moreover, PbO has excellent sensitivity to reflected rays, owing to its high atomic number (Z Pb: 82, Z O: 8) and density (ρPbO: 9.53 g/cm3). We applied PbO to a dosimeter for QA in a brachytherapy device and attempted to increase the signal stability with a parylene coating for performance improvement. Subsequently, a comparative analysis was performed with a PbO dosimeter that was not coated with parylene to determine whether the fabricated dosimeter is applicable as a dosimeter for QA of the brachytherapy device, by analyzing the reproducibility, linearity, percentage interval distance (PID), and angular dependence in the 192Ir source used for brachytherapy. The RSD of the non-parylene PbO dosimeter was 0.85%, and the RSD of the parylene PbO dosimeter was 0.40% in the reproducibility results. In the linearity evaluation results, the R 2 value of the non-parylene PbO dosimeter was 0.9996, and that of the parylene PbO dosimeter was 0.9997 In the PID evaluation results, the difference in the intensity distribution measured according to the distance due to the dose was attenuated at the coated parylene in the case of the parylene PbO dosimeter. Therefore, adjustments using correction coefficients are required for suitable performance. In the angular dependence evaluation results, the parylene PbO dosimeter had 3.44% less angular dependence than the non-parylene dosimeter at an angle of 45°. The parylene-coated PbO dosimeter showed better performance than the non-parylene-coated PbO dosimeter in terms of the reproducibility, linearity, and angular dependence. Therefore, it is considered that the parylene-coated PbO dosimeter can be implemented for QA of brachytherapy devices.

Development and evaluation of lead(II) iodide-based polycrystalline digital dosimeter for quality assurance in brachytherapy

2021 ◽  
Vol 16 (11) ◽  
pp. P11021
Author(s):  
S.W. Yang ◽  
M.J. Han ◽  
S.K. Park
Keyword(s):  
Quality Assurance ◽  
Angular Dependence ◽  
Radioactive Isotope ◽  
The Body ◽  
Evaluation Criterion ◽  
High Dose ◽  
Video Monitor ◽  
Dose Rates ◽  
Relative Standard ◽  
Interval Distance

Abstract Brachytherapy is a cancer treatment that involves intensively irradiating a tumor by placing a sealed radioactive isotope inside the body. Determining the position of the source through accurate quality assurance (QA) is important, because brachytherapy uses radioactive isotope sources with high dose rates. However, in clinical practice, the source position is determined with the naked eye through the use of a ruler, autoradiograph, video monitor, etc., which yields inaccurate results. Therefore, in this study, a lead (II) iodide (PbI2) based polycrystalline digital dosimeter that can measure the relative dose was developed for the QA of the brachytherapy device, and its applicability was evaluated in terms of reproducibility, linearity, percentage interval distance (PID), and angular dependence. Reproducibility evaluation yielded a relative standard deviation value of 1.41%, which satisfied the evaluation criterion of 1.5%. The linearity evaluation yielded an R2 value of 0.9993, which satisfied the evaluation criterion of 0.9990. The PID evaluation revealed that, as the distance from the source increased, the signal decreased according to the inverse-square law. When the PbI2-based digital dosimeter was rotated up to 45°, a difference of up to 13.20% in the angular dependence was observed. Thus, the dosimeter fabricated in this experiment met all the criteria of the aforementioned evaluations. Therefore, it is considered to be highly applicable as a dosimeter for the QA of brachytherapy devices.

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

The Difference in Sensing Properties Towards Anions between Two Pyridinium Amide-Based Receptors with a Subtle Change of H-Bond Position

2020 ◽  
Vol 17 (6) ◽  
pp. 472-478
Author(s):  
Wei-tao Gong ◽  
Wei-dong Qu ◽  
Guiling Ning
Keyword(s):  
Fluorescence Enhancement ◽  
Small Difference ◽  
Fluorescence Emission ◽  
Subtle Change ◽  
Sensing Properties ◽  
Naked Eye ◽  
Recognition Ability ◽  
The Difference ◽  
L1 And L2

Two pyridinium amide-based receptors L1 and L2 with a small difference of H-bond position of the amide have been synthesized and characterized. Interestingly, they exhibited a huge difference in sensing towards AcO- and H2PO4 -, respectively. Receptor L1 was found to be ‘naked-eye’ selective for AcO- anions, while receptor L2 showed clear fluorescence enhancement selective to H2PO4 - anion. The recognition ability has been established by fluorescence emission, UV-vis spectra, and 1HNMR titration.

scholarly journals Effect of Citric Acid on Color Changes of Calcium Silicate-Based Cements an In Vitro Study

2021 ◽  
Vol 11 (5) ◽  
pp. 2339
Author(s):  
Joanna Metlerska ◽  
Till Dammaschke ◽  
Mariusz Lipski ◽  
Irini Fagogeni ◽  
Anna Machoy-Mokrzyńska ◽  
...  
Keyword(s):  
Citric Acid ◽  
Calcium Silicate ◽  
In Vitro Study ◽  
Vitro Study ◽  
Color Measurement ◽  
Color Changes ◽  
Naked Eye ◽  
Root Canal Irrigants ◽  
The Difference

The aim of the present in vitro study was to investigate the effects of 10% and 40% citric acid (CA) on the color of calcium silicate–based cements (CSCs) in comparison to the effects of common root canal irrigants. Samples of six CSCs (n = 6)—ProRoot MTA (Dentsply, Tulsa, OK, USA), Biodentine (Septodont, Saint-Maur-des-Fossés, France), MTA Plus (Avalon Biomed Inc, by Prevest Denpro Limited, Jammu, India), MTA Repair HP (Angelus, Londrina, PR, Brazil), Ortho MTA (BioMTA, Seoul, Korea), and Retro MTA (BioMTA, Seoul, Korea)—were immersed in 10% and 40% CA as well as 15% EDTA, 2% NaOCl, 2% CHX, and 0.9% NaCl for 15 min, 1 h, and 24 h. ΔE values, representing the difference between the final and baseline values of the color components, were then determined using a VITA Easyshade Compact 5.0 spectrophotometer. Naked-eye evaluation of the changes in color and structures of the materials was performed using our own scale. Upon immersion of the materials in both 10% and 40% CA, there were statistically significant differences between spectrophotometric color measurement results for all CSCs (P < 0.05). However, CA does not cause dark discoloration, observable with the naked eye, of any of the materials, such as NaOCl and CHX. Significant statistical differences were also found between all CSCs in terms of submersion duration (P < 0.05). CA, which could be an alternative to EDTA use, caused greater CSCs discoloration and changed some of their structures. Unless required by the therapeutic procedure, clinicians should pay attention to the fact that the irrigant may affect the CSCs discoloration and minimize the contact time of irrigant with CSCs.

Make Use of the Difference of Failure and Exit to Improve the Operation Efficiency

2020 ◽  
pp. 164-184
Author(s):  
Yangyang Chen ◽  
Weiwei Dong ◽  
Dixuan Zhang ◽  
Mingwei Jin
Keyword(s):  
High Probability ◽  
Business Failure ◽  
Entrepreneurial Ecosystem ◽  
Operation Efficiency ◽  
Know How ◽  
Serial Entrepreneurship ◽  
Financial Condition ◽  
The Difference ◽  
Failure Experience ◽  
Entrepreneurial Exit

As business failure is a high probability event that influences the operation efficiency of the entrepreneurial ecosystem, it is necessary to know how to manage business failure experience to promote serial entrepreneurship and improve circulation in the ecosystem. While most scholars agree that it is different between failure and exit, DeTienne suggests that exit could be a way to avoid failure and protect the passion and financial condition of entrepreneurs. Therefore, this chapter analyzes the difference of failure and exit and conducts a model to help entrepreneurs decide whether to exit and how to choose a better way to exit entrepreneurship. In the meantime, this chapter analyzes why entrepreneurial exit can improve the operation efficiency of entrepreneurial ecosystem, and also it would give some ideas about how to bound from failure and benefit from failure to do better next time. After reading this chapter, entrepreneurs have the idea that failure is controllable and exit may be a restart to do business more successfully.

The Triple-Point Planet

2016 ◽  
Author(s):  
Ben McFarland
Keyword(s):  
Middle English ◽  
Family Resemblance ◽  
The Moon ◽  
The Road ◽  
Naked Eye ◽  
Third Phase ◽  
The Family ◽  
The Us ◽  
Let's Move ◽  
The Difference

Let’s move to a vantage point a little quieter: the surface of the moon. It is so still that Neil Armstrong’s footprints remain undisturbed. The only reason the US flag there appears to “fly” is that a wire holds it up. The moon and Mercury stayed still as Mars, Venus, and Earth moved on down the road of geological development. The moon is a “steady” environment, a word whose Middle English roots are appropriately tangled with the word for “sterile.” Nothing moves on the moon, but in its sky Mars, Venus, and Earth move in their orbits, just as they moved on in complexity 4 billion years ago. Out of the whole solar system, Mars and Venus are the most like Earth in size, position, and composition. Mars is smaller, but Venus could be Earth’s twin in size. If Earth and Venus were separated at birth, then something happened to obscure the family resemblance: liquid water brought life. To chemists, liquid is the third phase of matter, between solid and gas, and its presence made all the difference. Mars gleams a bright blood red even to the naked eye, while Venus is choked with thick yellow bands of clouds. Mars is cold enough to have carbon dioxide snow, while Venus is hot enough to melt tin and boil water. Earth’s blue oceans and green continents provide a bright, primary contrast. These three siblings have drastically different fortunes. At first, they looked the same, colored with black mafic basalt and glowing red magma. The original planets were all so hot that their atmospheres were driven off into space. The oceans and the air came from within. Steam condensed into oceans on each planet’s cool basalt surface. Oceans changed the planet. Water is a transformative chemical, small yet highly charged, seeping into the smallest cracks, dissolving what it can and carrying those things long distances. Venus, Earth, and Mars do not look like the moon because they have been washed in water. Mars is dry now, but the Curiosity rover left no doubt that the red planet was first blue with water.

scholarly journals Monopulse Antenna Based on Singular Spoof Surface Plasmon Polariton Structure for Angle Measurement

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2156
Author(s):  
Shunli Li ◽  
Qiuyi Zhang ◽  
Jinlun Li ◽  
Hongxin Zhao ◽  
Xiaoxing Yin ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Electromagnetic Waves ◽  
Surface Plasmon Polariton ◽  
Coplanar Waveguide ◽  
Direction Finding ◽  
High Accuracy ◽  
Angle Measurement ◽  
Waveguide Transition ◽  
Plasmon Polariton ◽  
The Difference

Direction finding and target tracking make demanding requirements on the measurement of incoming angles of electromagnetic waves. A monopulse antenna, based on the singular symmetric spoof surface plasmon polariton (SSPP) structure, is proposed for high-accuracy angle sensing. The singular SSPP structure is composed of periodic corrugated grooves for the confinement of the electromagnetic fields. Due to the microstrip–coplanar waveguide transition, the fields along both sides of the SSPP add constructively to form the endfire beam at the sum port and destructively to form the null radiation in the endfire direction at the difference port. An optimization based on the team progress algorithm is adopted to facilitate this antenna design. A prototype is designed and fabricated to validate the design principle, and measured results agree with the simulation. The proposed antenna shows a wide bandwidth ranging from 5.0 GHz to 7.5 GHz for both the sum and difference ports with the return loss greater than 10 dB, realizing a relative bandwidth of 40%. The isolation for the sum and difference ports is higher than 21 dB, and the null depth is larger than 20 dB over the entire operating range, which is favorable for the high accuracy angle sensing and measurement. This monopulse antenna has broad prospect in angle measuring systems such as direction finding and radar tracking scenes.

scholarly journals Casimir force induced by electromagnetic wave polarization in Kerr, Gödel and Bianchi–I spacetimes

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Felipe A. Asenjo ◽  
Sergio A. Hojman
Keyword(s):  
Electromagnetic Waves ◽  
Casimir Force ◽  
Polarized Light ◽  
Casimir Forces ◽  
Circularly Polarized Light ◽  
Bianchi I ◽  
Phase Velocities ◽  
Light Waves ◽  
Waves Propagation ◽  
The Difference

AbstractElectromagnetic waves propagation on either rotating or anisotropic spacetime backgrounds (such as Kerr and Gödel metrics, or Bianchi–I metric) produce a reduction of the magnitude of Casimir forces between plates. These curved spacetimes behave as chiral or birefringent materials producing dispersion of electromagnetic waves, in such a way that right– and left–circularly polarized light waves propagate with different phase velocities. Results are explicitly calculated for discussed cases. The difference on the wavevectors of the two polarized electromagnetic waves produces an abatement of a Casimir force which depends on the interaction between the polarization of electromagnetic waves and the properties of the spacetime.

An efficient non-reaction based colorimetric and fluorescent probe for the highly selective discrimination of Pd0 and Pd2+ in aqueous media

RSC Advances ◽  
2016 ◽  
Vol 6 (65) ◽  
pp. 60546-60549 ◽  
Author(s):  
Lubna Rasheed ◽  
Muhammad Yousuf ◽  
Il Seung Youn ◽  
Genggongwo Shi ◽  
Kwang S. Kim
Keyword(s):  
Fluorescent Probe ◽  
High Selectivity ◽  
Aqueous Media ◽  
Oxidation States ◽  
Probe Molecule ◽  
Naked Eye ◽  
Fluorogenic Probe ◽  
The Difference

A novel anthraquinone-imidazole based colorimetric and fluorogenic probe 1 discriminates the oxidation states of Pd0 and Pd2+ by naked eye with high selectivity in aqueous media due to the difference in coordination in the pocket of probe molecule.

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