Fig 2 - available from: Radiation Oncology
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(a) Scanning Acoustic Microscopy (SAM) System (b) Schematic representation of tissue sectioning (cutting points from enamel and longutidunal direction) and localization for the measurement. (c) Schematic representation of acoustic impedance measurement mode. In this case, water is used as substrate. Tooth sample is not necessarily thin sliced. Just front surface must be polished to be very flat for the acoustic impedance measurement of the tooth sample
Source publication
Background:
On the elastic profiles of human teeth after radiotherapy for head and neck cancers, generation of dental complications, which may bring several side effects preventing the quality of life, has not well clarified. Thus, we aimed to show the applicability of using 320 MHz Scanning Acoustic Microscopy (SAM) in the evaluation of the tooth...
Contexts in source publication
Context 1
... from 200 to 400 MHz was focused on the junction between the tooth and the substrate, and passed through the substrate. The 320 MHz transducer was positioned under the sample on the X-Y stage where linear servo motors drove the both X-scan and Y-scan. Polystyrene petri dish holding the tooth sample was placed above the transducer as shown in Fig. 2 (created by BioRender), in which the front surface of the tooth was in contact with the transducer. Acoustic impedance of tooth was figured out using water as a substrate. The acoustic impedance of water as a substrate was 1.5 MRayl. Each tooth sample was irradiated and scanned along the X-Y axes in a frame with 300 × 300 pixels. ...
Context 2
... from 200 to 400 MHz was focused on the junction between the tooth and the substrate, and passed through the substrate. The 320 MHz transducer was positioned under the sample on the X-Y stage where linear servo motors drove the both X-scan and Y-scan. Polystyrene petri dish holding the tooth sample was placed above the transducer as shown in Fig. 2 (created by BioRender), in which the front surface of the tooth was in contact with the transducer. Acoustic impedance of tooth was figured out using water as a substrate. The acoustic impedance of water as a substrate was 1.5 MRayl. Each tooth sample was irradiated and scanned along the X-Y axes in a frame with 300 × 300 pixels. ...
Citations
... The authors of one study [38] observed an increased number of visible macrofractures in the enamel. Notably, most selected-study results agreed that 60-Gy-irradiated enamel exhibited micromorphological damage, such as appearance of porosities, microcracks and prismatic structure disappearance [17,21,[24][25][26]31,37,[39][40][41][42]. No or only minor changes were observed in two studies [28,36]. ...
... Radiation impact on the structural properties of coronal dentin is summarized in Table 7. According to all studies [19,25,26,39,41,42], the dentinal tubular structure disappeared, with tubule obliteration and formation of cracks, assessed with two methods (scanning electron microscopy (SEM) or laser confocal microscopy). ...
... The elastic modulus was measured in two investigations that reported different results [18,21]. Acoustic impedance (representing the tissue elastic mechanical properties) was decreased after 60-Gy irradiation according to another study [39]. ...
Objectives
The conventional radiotherapy protocol to treat head-and-neck cancer is usually followed by tooth-decay onset. Radiation impact on mineralized tooth structures is not well-understood. This systematic review aimed to collect the recorded effects of therapeutic radiation on tooth chemical, structural and mechanical properties, in relation with their means of investigation.
Data
Systematic search (January 01 2012 – September 30 2021) terms were “Radiotherapy”, “Radiation effects”, “Dental enamel”, “Dentin”, “Human” and “Radiotherapy” NOT “Laser”.
Sources
PubMed, DOSS and Embase databases were searched.
Study selection
Selected studies compared dental enamel, coronal and root dentin properties before and after in vitro or in vivo irradiation up to 80 Gy.
Results
The systematic search identified 353 different articles, with 28 satisfying inclusion criteria. Their reference lists provided two more. Twenty-two studies evaluated dental enamel evolution, nine assessed coronal dentin and eight concerned root dentin. Coronal and root dentin results indicate a major impact of the radiation on their organic matrix. Dental enamel’s chemical properties are less modified. Enamel and root dentin’s hardness are decreased by therapeutic radiation, but no consensus arises for coronal dentin.
Conclusions
Our findings revealed some interesting information about enzymatic degradation mechanisms of dentin organic matrix and highlighted that dental hard-tissue characterization requires highly specific expertise in materials science. That scientific knowledge is necessary to design suitable protocols, adequately analyze the obtained data, and, thus, provide relevant conclusions.
Clinical Significance statement
Better knowledge and understanding of the mechanisms involved in the degradation of enamel and dentin would enable development of new preventive and therapeutic methods for improved medical care of patients undergoing radiotherapy.
... For each irradiation, the position accuracy of the tubes inside the rice phantom was controlled by comparing DRR and kV images. 78 ...
Radiation therapy is widely used as a treatment tool for malignancies. However, radiation-related complications are still unavoidable risks for off-target cells. Little is known about radiation therapy's possible effects on mechanical features of the off-target cells such as human red blood cells (RBCs). RBCs are nucleus-free circulating cells that can deform without losing functionality in healthy conditions. Thus, to evaluate in vitro effects of radiation therapy on the healthy plasma membrane of cells, RBCs were selected as a primary test model. RBCs were exposed to clinically prescribed radiotherapy doses of 2 Gy, 12 Gy and, 25 Gy, and each radiotherapy dose group was compared to a non-irradiated group. Cells were characterized by stretching using dual-beam optical tweezers and compared using the resulting deformability index. The group receiving the highest radiation dose was found statistically distinguishable from the control group (DI 0Gy ¼ 0.33 AE 0.08), and revealed the highest deformability index (DI 25Gy ¼ 0.38 AE 0.11, p ¼ 0.0068), while no significant differences were found for 2 Gy (DI 2Gy ¼ 0.33 AE 0.08, p ¼ 0.9) and 12 Gy (DI 12Gy ¼ 0.31 AE 0.09, p ¼ 0.2) dose groups. Based on these findings, we conclude that radiotherapy exposure may alter the deformability of red blood cells depending on the dose amount, and measurement of deformability index by dual-beam optical tweezers can serve as a sensitive biomarker to probe responses of cells to the radiotherapy.
... The acoustic waves propagate through the lens body ( Fig. 1) and are focused sharply by the spherical cavity of the lens into a diffraction limited point at the interface between a coupling fluid and the sample. Reflection occurs when a mismatch in the acoustic impedance is realized at interfaces (Demirkan et al., 2020). For normal incidence, it is the product of the mechanical density and velocity of ultrasound. ...
Scanning acoustic microscopy (SAM) is used to characterize welds in a trade thermoplastic polymer (ABS) manufactured by injection-molding, particularly at the locations of weld-lines known to form as unavoidable significant defects. Acoustic micrographs obtained at 420 MHz clearly resolve the weld lines with morphological deformations and microelastic heterogenity. This is also where terahertz (THz) measurements, carried out in support of the SAM study, reveal enhanced birefringence corresponding to the location of these lines enabling verification of the SAM results. Rayleigh surface acoustic waves (RSAW), quantified by V(z) curves (with defocusing distance of 85 µm), are found to propagate slower in regions close to the weld lines than in regions distant from these lines. The discrepancy of about 100 m/s in the velocity of RSAW indicates a large variation in the micro-elastic properties between areas close to and distant from the weld lines. The spatial variations in velocity (VR) of RSAWs indicate anisotropic propagation of the differently polarized ultrasonic waves.
Scanning Acoustic Microscopy (SAM) emerges as a versatile label-free imaging technology with broad applications in biomedical imaging, non-destructive testing, and material research. This article resents a framework for the estimation of stochastic impedance through SAM, with a particular focus on its application to the salmon fish scale. The framework leverages uncertain reflectance, marking its pioneering application to uncertainty quantification in the acoustic impedance of fish scales through acoustic responses. The study uses maximal overlap discrete wavelet transform, to decompose acoustic responses effectively and is further processed to predict the acoustic impedance. To establish the effectiveness of the proposed framework, well-known materials like a pair of target medium (polyvinylidene fluoride) and reference medium (polyimide) are employed for impedance characterization. Results demonstrate over 90% accuracy in PVDF impedance estimation, validating the framework. A stochastic impedance map, using Kriging with a Gaussian variogram, offers insights into the complex biomechanics of a
fish scale.
In the current study, silicon was utilized as the substrate material and, then, the TiO2 depositions with 100 nm, 300 nm, 500 nm and 700 nm were done onto substrates as thin films at room temperature by a radio frequency (rf) magnetron sputtering method. The binding energy, the surface roughness, elemental analysis and the specific acoustic impedance have been determined via X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) and scanning acoustic microscopy (SAM), respectively. AFM analysis represented that the root mean square roughness values changed in the range of 0.72 nm–1.22 nm, gradually by the increase in thickness. Two-dimensional acoustic images were recorded by SAM with 80 MHz transducer. The mean and standard deviation values of acoustic impedance were found as 3.151 ± 0.080 MRayl for 100 nm, 3.366 ± 0.080 MRayl for 300 nm, 3.379 ± 0.067 MRayl for 500 nm and, 3.394 ± 0.065 MRayl for 700 nm. SAM results pointed out that the hardness of films increased with increasing thickness. Moreover, the surface defects at the micrometer level were demonstrated. The success of imaging films indicated the potential of SAM in monitoring as well as the inspection of flat two-dimensional surfaces.
