Pub Date : 2022-06-01DOI: 10.1016/j.phmed.2021.100043
Michiel Postema
In a recent issue of Physics in Medicine, Akashi et al. demonstrated increased mortality of HeLa cells in combination with phospholipid-shelled microbubbles under high-amplitude sonication in an in-vitro experimental setup [1]. The authors attributed the increased mortality to cell damage caused by microbubble dynamics and mentioned the term sonoporation early in their paper. Their findings are a most valuable contribution with regards to ultrasonic imaging safety standards. However, the findings would be even more beneficial to the drug delivery community, provided they could be linked to previous outcomes on in-vitro experimental sonoporation. The purpose of this paper is to briefly underscore previous works with similar setups, highlighting the many agreements between early and recent work.
{"title":"A brief note on experimental setups for in-vitro optical observations of HeLa cells and phospholipid-shelled microbubbles subjected to ultrasound","authors":"Michiel Postema","doi":"10.1016/j.phmed.2021.100043","DOIUrl":"10.1016/j.phmed.2021.100043","url":null,"abstract":"<div><p>In a recent issue of Physics in Medicine, Akashi et al. demonstrated increased mortality of HeLa cells in combination with phospholipid-shelled microbubbles under high-amplitude sonication in an in-vitro experimental setup [1]. The authors attributed the increased mortality to cell damage caused by microbubble dynamics and mentioned the term sonoporation early in their paper. Their findings are a most valuable contribution with regards to ultrasonic imaging safety standards. However, the findings would be even more beneficial to the drug delivery community, provided they could be linked to previous outcomes on in-vitro experimental sonoporation. The purpose of this paper is to briefly underscore previous works with similar setups, highlighting the many agreements between early and recent work.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352451021000093/pdfft?md5=c52dbbffd544f11dc796a8c240881694&pid=1-s2.0-S2352451021000093-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44089979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-01DOI: 10.1016/j.phmed.2021.100046
Manuel Feurhuber , Ralf Neuschwander , Thomas Taupitz , Carsten Frank , Christoph Hochenauer , Valentin Schwarz
In this study, inactivation kinetics of Geobacillus stearothermophilus spores were evaluated in different sterilization environments. The kinetics were analysed and mathematically modelled based on experimental data collected. The inactivation kinetics were measured precisely in moist heat environments using different sterilization temperatures and holding times. All measured inactivation times were shorter than the inactivation time indicated by the Biological Indicator (BI) manufacturer. Increasing sterilization efficiency was found in the following environments: air, saturated steam, wet steam, liquid water, dialysis solutions. Applying first- and second-order reaction kinetics approaches, formulas were derived from measured data that enabled bacterial inactivation to be modelled. A mathematical first-order reaction kinetic modelling approach could be taken to effectively predict inactivation kinetics for G. stearothermophilus spores based on the experimentally measured data collected in wet steam and air environments. A second-order reaction kinetics approach could be taken, however, to model measured data more accurately in liquid water and dialysis-solution environments. The mathematical models presented here can be applied to describe inactivation kinetics for G. stearothermophilus spores in different sterilization test environments or for any given sterilization temperature profile. These findings can be used to improve the quality of sterilization processes.
{"title":"Mathematically modelling the inactivation kinetics of Geobacillus stearothermophilus spores: Effects of sterilization environments and temperature profiles","authors":"Manuel Feurhuber , Ralf Neuschwander , Thomas Taupitz , Carsten Frank , Christoph Hochenauer , Valentin Schwarz","doi":"10.1016/j.phmed.2021.100046","DOIUrl":"10.1016/j.phmed.2021.100046","url":null,"abstract":"<div><p>In this study, inactivation kinetics of <em>Geobacillus stearothermophilus</em> spores were evaluated in different sterilization environments. The kinetics were analysed and mathematically modelled based on experimental data collected. The inactivation kinetics were measured precisely in moist heat environments using different sterilization temperatures and holding times. All measured inactivation times were shorter than the inactivation time indicated by the Biological Indicator (BI) manufacturer. Increasing sterilization efficiency was found in the following environments: air, saturated steam, wet steam, liquid water, dialysis solutions. Applying first- and second-order reaction kinetics approaches, formulas were derived from measured data that enabled bacterial inactivation to be modelled. A mathematical first-order reaction kinetic modelling approach could be taken to effectively predict inactivation kinetics for <em>G. stearothermophilus</em> spores based on the experimentally measured data collected in wet steam and air environments. A second-order reaction kinetics approach could be taken, however, to model measured data more accurately in liquid water and dialysis-solution environments. The mathematical models presented here can be applied to describe inactivation kinetics for <em>G. stearothermophilus</em> spores in different sterilization test environments or for any given sterilization temperature profile. These findings can be used to improve the quality of sterilization processes.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352451021000123/pdfft?md5=3e35a1cfdfcb4b275f928cd1b47a5f45&pid=1-s2.0-S2352451021000123-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45867903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100040
Lennart Guntenhöner, Katharina Foremny, Jan Stieghorst, Michaela Kreienmeyer, Theodor Doll
Scientific efforts towards nerve regeneration and nerve-electrode interfaces depend on the possibility of guided neurite growth. The quantification and tracing of neurite growth during experiments is therefore essential. While tracing is possible under 2D cell culture conditions, it gets more complex when analysing three dimensionally orientated neurite pathways resulting in the ongoing development of 3D neuron tracing software. However, the quantification of short vertical neurite sprouts remains complicated due to difficult distinction from small cell body parts. With this study, we present a new method for precise identification and quantification of short neurite sprouts growing vertically from the surface of a track-etched membrane into 8 μm diameter pores of the membrane. Based on collected radius data from identified horizontally orientated neurites, a 95% reference interval for average radii of neurites was established and the limits were applied to trace neurite sprouts in the membrane's pores. Following this procedure, neurites were successfully distinguished from small cell body parts. This study demonstrates how to identify short neurite sprouts by assessing number, length, and radius with an additional checkpoint for bias detection.
{"title":"3D quantification of short vertical neurites in membrane pores and their differentiation from other cell parts","authors":"Lennart Guntenhöner, Katharina Foremny, Jan Stieghorst, Michaela Kreienmeyer, Theodor Doll","doi":"10.1016/j.phmed.2021.100040","DOIUrl":"10.1016/j.phmed.2021.100040","url":null,"abstract":"<div><p>Scientific efforts towards nerve regeneration and nerve-electrode interfaces depend on the possibility of guided neurite growth. The quantification and tracing of neurite growth during experiments is therefore essential. While tracing is possible under 2D cell culture conditions, it gets more complex when analysing three dimensionally orientated neurite pathways resulting in the ongoing development of 3D neuron tracing software. However, the quantification of short vertical neurite sprouts remains complicated due to difficult distinction from small cell body parts. With this study, we present a new method for precise identification and quantification of short neurite sprouts growing vertically from the surface of a track-etched membrane into 8 μm diameter pores of the membrane. Based on collected radius data from identified horizontally orientated neurites, a 95% reference interval for average radii of neurites was established and the limits were applied to trace neurite sprouts in the membrane's pores. Following this procedure, neurites were successfully distinguished from small cell body parts. This study demonstrates how to identify short neurite sprouts by assessing number, length, and radius with an additional checkpoint for bias detection.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.phmed.2021.100040","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45224032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100045
Florian Pfaffeneder-Mantai , Cezarina Cela Mardare , Dritan Turhani , Achim Walter Hassel , Christoph Kleber
Objectives
Without rotating instruments, for example diamond-coated drills with a core made of stainless steel, the dental routine would be unimaginable, since these are used in almost every dental activity and are thus indispensable for the professional practice. Unfortunately, such drills release Nickel particles to a high content into the cooling water of the drill. Values up to 1.3 mg/l Nickel were found by ICP – OES in the cooling water of the drillers which is of course also transferred into the patient's oral cavity with possible severe negative effects. Therefore, novel plating procedures have to be developed to increase the patients (and dentists) safety during treatment.
Methods
Dispersion layers with the hard metal Tungsten carbide (WC) particles on stainless steel blanks were deposited following two synthesis routines (i) Plasma-Electrolytic Oxidation (PEO) and (ii) galvanic plating out of a Watts bath. Both were accomplished using water-based electrolytes.
Results
In order to verify the dental applicability of the developed coatings, tests-drills were accomplished under defined conditions on plastic teeth for the sake of reproducibility.
Commercially produced drills were compared with the newly plated ones by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and the drilling cooling water was examined for heavy metal residues using Inductively Coupled Plasma (ICP) analytics. The resulting grinding patterns in the plastic teeth were investigated by light microscopy and SEM.
It could be shown that dispersion layers plated by a galvanic procedure showed a reduced Nickel release compared to a commercial driller by factor 7.6 and 13.4 compared to PEO plated ones during dental treatments.
Conclusions
Following the clinical significance the Watts bath plated drillers showed a better WC particle distribution on the surface and better abrasive properties during the drilling experiments compared to PEO plated drillers. In addition the Nickel release during dental use is much less from the galvanic treated ones. By optimising the plating condition from the Watts dispersion bath further novel drilling devices with significantly reduced release of Nickel particles can be developed for the benefit of the patients.
{"title":"Development of dispersion layers for dental drills with reduced nickel release","authors":"Florian Pfaffeneder-Mantai , Cezarina Cela Mardare , Dritan Turhani , Achim Walter Hassel , Christoph Kleber","doi":"10.1016/j.phmed.2021.100045","DOIUrl":"10.1016/j.phmed.2021.100045","url":null,"abstract":"<div><h3>Objectives</h3><p>Without rotating instruments, for example diamond-coated drills with a core made of stainless steel, the dental routine would be unimaginable, since these are used in almost every dental activity and are thus indispensable for the professional practice. Unfortunately, such drills release Nickel particles to a high content into the cooling water of the drill. Values up to 1.3 mg/l Nickel were found by ICP – OES in the cooling water of the drillers which is of course also transferred into the patient's oral cavity with possible severe negative effects. Therefore, novel plating procedures have to be developed to increase the patients (and dentists) safety during treatment.</p></div><div><h3>Methods</h3><p>Dispersion layers with the hard metal Tungsten carbide (WC) particles on stainless steel blanks were deposited following two synthesis routines (i) Plasma-Electrolytic Oxidation (PEO) and (ii) galvanic plating out of a Watts bath. Both were accomplished using water-based electrolytes.</p></div><div><h3>Results</h3><p>In order to verify the dental applicability of the developed coatings, tests-drills were accomplished under defined conditions on plastic teeth for the sake of reproducibility.</p><p>Commercially produced drills were compared with the newly plated ones by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and the drilling cooling water was examined for heavy metal residues using Inductively Coupled Plasma (ICP) analytics. The resulting grinding patterns in the plastic teeth were investigated by light microscopy and SEM.</p><p>It could be shown that dispersion layers plated by a galvanic procedure showed a reduced Nickel release compared to a commercial driller by factor 7.6 and 13.4 compared to PEO plated ones during dental treatments.</p></div><div><h3>Conclusions</h3><p>Following the clinical significance the Watts bath plated drillers showed a better WC particle distribution on the surface and better abrasive properties during the drilling experiments compared to PEO plated drillers. In addition the Nickel release during dental use is much less from the galvanic treated ones. By optimising the plating condition from the Watts dispersion bath further novel drilling devices with significantly reduced release of Nickel particles can be developed for the benefit of the patients.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352451021000111/pdfft?md5=83bdf00db3151e51c488218c73e36ba0&pid=1-s2.0-S2352451021000111-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46803357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100041
Ryuta Akashi , Arisa Hirayama , Daisuke Koyama
Drug delivery systems (DDS) using ultrasound and microbubbles have been proposed to enhance drug efficacy and reduce undesirable side effects. While several researchers have reported the vibrational characteristics of lipid-coated microbubbles under ultrasound irradiation and the effects on cell damage, it is necessary to quantitatively evaluate the effects to establish the safety criteria of ultrasound DDS. In this paper, the effects of the microbubble behavior on adhesive HeLa cells under ultrasound irradiation were evaluated. Microbubbles coated with a phospholipid shell were fabricated and two size distributions of bubbles were prepared. The HeLa cells were exposed to pulsed ultrasound at 1 MHz with microbubbles in a water tank, and the cell mortality rate was measured quantitatively under fluorescent observation. The collapse of the microbubbles with a resonance size of approximately 2 μm enhanced the cell mortality rate. Greater sound pressure amplitude produced a higher collapsing rate of the microbubble and cell mortality rate, implying the destruction of microbubbles with resonance size generated a shock wave or microjet, inducing cell damage. While the cell mortality rate decreased exponentially with the increase in distance between cells and microbubbles, a smaller distance induced a higher cell mortality rate: 84% of the HeLa cells died within 2.5 μm of microbubbles produced by a pulsed ultrasound with 1.0 MPa at 1 MHz.
{"title":"Quantitative evaluation of the mortality rate of HeLa cells induced by microbubble vibration and collapse under pulsed ultrasound irradiation","authors":"Ryuta Akashi , Arisa Hirayama , Daisuke Koyama","doi":"10.1016/j.phmed.2021.100041","DOIUrl":"10.1016/j.phmed.2021.100041","url":null,"abstract":"<div><p>Drug delivery systems (DDS) using ultrasound and microbubbles have been proposed to enhance drug efficacy and reduce undesirable side effects. While several researchers have reported the vibrational characteristics of lipid-coated microbubbles under ultrasound irradiation and the effects on cell damage, it is necessary to quantitatively evaluate the effects to establish the safety criteria of ultrasound DDS. In this paper, the effects of the microbubble behavior on adhesive HeLa cells under ultrasound irradiation were evaluated. Microbubbles coated with a phospholipid shell were fabricated and two size distributions of bubbles were prepared. The HeLa cells were exposed to pulsed ultrasound at 1 MHz with microbubbles in a water tank, and the cell mortality rate was measured quantitatively under fluorescent observation. The collapse of the microbubbles with a resonance size of approximately 2 μm enhanced the cell mortality rate. Greater sound pressure amplitude produced a higher collapsing rate of the microbubble and cell mortality rate, implying the destruction of microbubbles with resonance size generated a shock wave or microjet, inducing cell damage. While the cell mortality rate decreased exponentially with the increase in distance between cells and microbubbles, a smaller distance induced a higher cell mortality rate: 84% of the HeLa cells died within 2.5 μm of microbubbles produced by a pulsed ultrasound with 1.0 MPa at 1 MHz.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.phmed.2021.100041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43221766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100039
Manuel Feurhuber , Ralf Neuschwander , Thomas Taupitz , Valentin Schwarz , Carsten Frank , Christoph Hochenauer
The aim of this study was to develop a Computational Fluid Dynamics (CFD) model to simulate the inactivation of bacterial spores of Geobacillus stearothermophilus inside a Peritoneal Dialysis Bag System (PDBS). The presented CFD model has three significant modifications in comparison to current state-of-the-art simulations of sterilization processes. (i) The CFD simulation can be used to consider the multiphase flow (water, steam, different dialysis solutions, non-condensable gases (NCGS)) inside the PDBS, the natural convection as well as the steam penetration. (ii) Experimentally obtained inactivation kinetics were added to the CFD code to enable simulation of the inactivation of G. stearothermophilus spores. (iii) The inactivation process of G. stearothermophilus spores was simulated in different sterilization environments which are present inside a PDBS. The CFD model was verified with measurements using Biological Indicators (BIs). Results showed that on the pre-CFD-simulated “worst case locations” CFD simulations and the BI-based verification were in well accordance.
By using the presented CFD model, the simulation of a moist heat sterilization process can be performed for any given sterilization cycle. In addition, the model is a powerful tool that can be used to optimize steam sterilization processes and guarantee a high level of sterilization efficiency and product safety.
{"title":"A Computational Fluid Dynamics (CFD) model to simulate the inactivation of Geobacillus stearothermophilus spores in different moist heat sterilization environments","authors":"Manuel Feurhuber , Ralf Neuschwander , Thomas Taupitz , Valentin Schwarz , Carsten Frank , Christoph Hochenauer","doi":"10.1016/j.phmed.2021.100039","DOIUrl":"10.1016/j.phmed.2021.100039","url":null,"abstract":"<div><p>The aim of this study was to develop a Computational Fluid Dynamics (CFD) model to simulate the inactivation of bacterial spores of <em>Geobacillus stearothermophilus</em> inside a Peritoneal Dialysis Bag System (PDBS). The presented CFD model has three significant modifications in comparison to current state-of-the-art simulations of sterilization processes. (i) The CFD simulation can be used to consider the multiphase flow (water, steam, different dialysis solutions, non-condensable gases (NCGS)) inside the PDBS, the natural convection as well as the steam penetration. (ii) Experimentally obtained inactivation kinetics were added to the CFD code to enable simulation of the inactivation of <em>G. stearothermophilus</em> spores. (iii) The inactivation process of <em>G. stearothermophilus</em> spores was simulated in different sterilization environments which are present inside a PDBS. The CFD model was verified with measurements using Biological Indicators (BIs). Results showed that on the pre-CFD-simulated “worst case locations” CFD simulations and the BI-based verification were in well accordance.</p><p>By using the presented CFD model, the simulation of a moist heat sterilization process can be performed for any given sterilization cycle. In addition, the model is a powerful tool that can be used to optimize steam sterilization processes and guarantee a high level of sterilization efficiency and product safety.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.phmed.2021.100039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43865928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100036
Mohammad Ali Saghiri , Devyani Nath , Onyeka Oguagha , Ali Mohammad Saghiri , Steven M. Morgano
Objective
To propose a method to develop 3-dimensional (3D) models of regular and orthodontic typodonts by using their 2-dimensional (2D) images, as an alternate method to 3D scanners.
Materials and methods
The mandibles of two typodonts, regular occlusion and malocclusion, were scanned by using a 3D scanner to generate their models. Captured scans were used to determine the accuracy of the existing method. One hundred images of each mandible were made by using a smartphone from various angles five times to create required and generate 3D models through the software. The percentage overlap of the hard tissues of the scans and the models superimposed within the group (repeatability test), and with each other (accuracy test) gathered the proposed method's accuracy and precision. The data were analyzed by using the Student's t-test.
Results
Ten scans and ten models were overlapped among themselves and each other and evaluated. Repeatability test; significant overlap in scans for both mandibles (regular and maloccluded), and their 3D model's counterparts (P < 0.05, CI 95%). Accuracy tests; significant overlap between both methods for both mandibles (P < 0.05, CI 95%).
Conclusion
The 2D images were successfully used to model the teeth (both regular and maloccluded) non-invasively. The proposed method showed high reproducibility as well as accuracy when compared to a commercially available 3D scanner.
Clinical significance
The 3D models for both regular teeth and teeth with malocclusions were modeled by using 2D images taken with a smartphone by using the novel method which was both reproducible and accurate.
目的提出一种利用常规正畸型牙的二维图像建立正畸型牙的三维模型的方法,作为三维扫描仪的替代方法。材料与方法采用三维扫描仪对正常咬合和错咬合两种类型的下颌进行扫描,生成其模型。捕获的扫描被用来确定现有方法的准确性。每个下颌骨用智能手机从不同角度拍摄了100张图像,共5次,通过软件创建所需的3D模型。扫描的硬组织与组内叠加的模型重叠的百分比(重复性测试)和相互重叠的百分比(准确性测试)汇总了所提出方法的准确性和精密度。采用学生t检验对数据进行分析。结果10个模型与10个扫描结果相互重叠并进行评价。可重复性测试;在扫描中,两个下颌骨(正常的和错咬合的)和它们的3D模型(P <0.05, ci 95%)。精度测试;两种方法在两个下颌骨的显著重叠(P <0.05, ci 95%)。结论二维图像可以成功地对正常牙和错颌牙进行无创建模。与市售的3D扫描仪相比,所提出的方法具有很高的再现性和准确性。临床意义利用智能手机拍摄的二维图像建立正常牙和错颌牙的三维模型,该方法重现性好,准确性高。
{"title":"A new reliable alternate method to an intraoral scanner (in-vitro study)","authors":"Mohammad Ali Saghiri , Devyani Nath , Onyeka Oguagha , Ali Mohammad Saghiri , Steven M. Morgano","doi":"10.1016/j.phmed.2021.100036","DOIUrl":"10.1016/j.phmed.2021.100036","url":null,"abstract":"<div><h3>Objective</h3><p>To propose a method to develop 3-dimensional (3D) models of regular and orthodontic typodonts by using their 2-dimensional (2D) images, as an alternate method to 3D scanners.</p></div><div><h3>Materials and methods</h3><p>The mandibles of two typodonts, regular occlusion and malocclusion, were scanned by using a 3D scanner to generate their models. Captured scans were used to determine the accuracy of the existing method. One hundred images of each mandible were made by using a smartphone from various angles five times to create required and generate 3D models through the software. The percentage overlap of the hard tissues of the scans and the models superimposed within the group (repeatability test), and with each other (accuracy test) gathered the proposed method's accuracy and precision. The data were analyzed by using the Student's t-test.</p></div><div><h3>Results</h3><p>Ten scans and ten models were overlapped among themselves and each other and evaluated. Repeatability test; significant overlap in scans for both mandibles (regular and maloccluded), and their 3D model's counterparts (P < 0.05, CI 95%). Accuracy tests; significant overlap between both methods for both mandibles (P < 0.05, CI 95%).</p></div><div><h3>Conclusion</h3><p>The 2D images were successfully used to model the teeth (both regular and maloccluded) non-invasively. The proposed method showed high reproducibility as well as accuracy when compared to a commercially available 3D scanner.</p></div><div><h3>Clinical significance</h3><p>The 3D models for both regular teeth and teeth with malocclusions were modeled by using 2D images taken with a smartphone by using the novel method which was both reproducible and accurate.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.phmed.2021.100036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43289198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100044
Morad El Kafhali , Mohammed Khalis , Marziyeh Tahmasbi , Rajaa Sebihi , Lida Velasquez Sierra
Background
With increasing application of Volumetric Modulated Arc Therapy (VMAT) and the complexity of treatment plans, necessity of patient-specific quality assurance procedures is raised. Therefore, this study aimed to perform VMAT plan control using the ArcCHECK® (Sun Nuclear) and the EPID (Electronic Portal Imaging Device) A-Si1000 and make a comparison.
Methods
The study was carried out at AL KAWTAR Oncology Center (Fez-Meknes/Morocco) with the TrueBeamTM accelerator and EclipseTM Treatment Planning System (TPS). GeoGebra 6.0 and Origin 2019 software were applied to statistical analysis and to reconstruct the dose distribution maps for ArcCHECK® Phantom, respectively. Gamma index test with the 3%/3 and 2%/2 mm criteria applied to compare two pretreatment quality control instrumentation.
Results
Although the EPID A-Si1000 and the ArcCHECK® phantom both were capable of performing VMAT plan control, results of gamma index analysis revealed some differences in the quality of the reviewed plans with the two devices.
Conclusion
based on the results, a single device to implement patient QA for complex VMAT plans may not be reliable. Therefore, to ensure patient protection against machine or human errors, applying the EPID A-Si1000 and the ArcCHECK® phantom both are proposed to evaluate the quality of complex VMAT plans for different cancer types.
{"title":"Clinical experiment on quality control comparison of complex treatment plans of the VMAT technique using a diode-based cylindrical phantom (ArcCHECK) and an amorphous silicon-based planar detector (A-Si1000)","authors":"Morad El Kafhali , Mohammed Khalis , Marziyeh Tahmasbi , Rajaa Sebihi , Lida Velasquez Sierra","doi":"10.1016/j.phmed.2021.100044","DOIUrl":"10.1016/j.phmed.2021.100044","url":null,"abstract":"<div><h3>Background</h3><p>With increasing application of Volumetric Modulated Arc Therapy (VMAT) and the complexity of treatment plans, necessity of patient-specific quality assurance procedures is raised. Therefore, this study aimed to perform VMAT plan control using the ArcCHECK® (Sun Nuclear) and the EPID (Electronic Portal Imaging Device) A-Si1000 and make a comparison.</p></div><div><h3>Methods</h3><p>The study was carried out at AL KAWTAR Oncology Center (Fez-Meknes/Morocco) with the TrueBeam<sup><em>TM</em></sup> accelerator and Eclipse<sup><em>TM</em></sup> Treatment Planning System (TPS). GeoGebra 6.0 and Origin 2019 software were applied to statistical analysis and to reconstruct the dose distribution maps for ArcCHECK® Phantom, respectively. Gamma index test with the 3%/3 and 2%/2 mm criteria applied to compare two pretreatment quality control instrumentation.</p></div><div><h3>Results</h3><p>Although the EPID A-Si1000 and the ArcCHECK® phantom both were capable of performing VMAT plan control, results of gamma index analysis revealed some differences in the quality of the reviewed plans with the two devices.</p></div><div><h3>Conclusion</h3><p>based on the results, a single device to implement patient QA for complex VMAT plans may not be reliable. Therefore, to ensure patient protection against machine or human errors, applying the EPID A-Si1000 and the ArcCHECK® phantom both are proposed to evaluate the quality of complex VMAT plans for different cancer types.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S235245102100010X/pdfft?md5=55272846f70a53b9690a59d770782cfd&pid=1-s2.0-S235245102100010X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42970830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100038
Derick Yongabi , Nathalie Mertens , Ronald Peeters
T1 mapping is crucial for many quantitative magnetic resonance imaging (MRI) procedures. However, studies have reported wide T1 variations, both in vivo and in vitro. Since clinical decisions depend on T1 relaxation times, evaluating the factors affecting their reproducibility is necessary. Available studies are limited in that they do not provide a comparative perspective on the variation of T1 relaxation times as a function of relevant parameters, such as pulse sequence type, magnetic field strength and how their interplay with the scanner model affects the resulting T1 values. To address these gaps, we imaged two phantoms modelling T1 of different samples at 1.5 T and 3.0 T using fast and slow inversion recovery (IR) sequences. The results show that T1 relaxation times from 3.0 T scanners are accurate and reproducible in terms of the expected reference values and when compared between different scanner models. Similarly, T1 values measured with the two pulse sequences were similar for all 3.0 T scanners. On the contrary, 1.5 T scanners exhibited larger discrepancies in the measured T1 compared with the reference values. In addition, 1.5 T scanners displayed less reproducibility in T1 relaxation time measurements across different 1.5 T scanners, and pulse sequences.
{"title":"Reproducibility of T1 relaxation times in diagnostic MRI: A phantom study","authors":"Derick Yongabi , Nathalie Mertens , Ronald Peeters","doi":"10.1016/j.phmed.2021.100038","DOIUrl":"10.1016/j.phmed.2021.100038","url":null,"abstract":"<div><p>T<sub>1</sub> mapping is crucial for many quantitative magnetic resonance imaging (MRI) procedures. However, studies have reported wide T<sub>1</sub> variations, both <em>in vivo</em> and <em>in vitro</em>. Since clinical decisions depend on T<sub>1</sub> relaxation times, evaluating the factors affecting their reproducibility is necessary. Available studies are limited in that they do not provide a comparative perspective on the variation of T<sub>1</sub> relaxation times as a function of relevant parameters, such as pulse sequence type, magnetic field strength and how their interplay with the scanner model affects the resulting T<sub>1</sub> values. To address these gaps, we imaged two phantoms modelling T<sub>1</sub> of different samples at 1.5 T and 3.0 T using fast and slow inversion recovery (IR) sequences. The results show that T<sub>1</sub> relaxation times from 3.0 T scanners are accurate and reproducible in terms of the expected reference values and when compared between different scanner models. Similarly, T<sub>1</sub> values measured with the two pulse sequences were similar for all 3.0 T scanners. On the contrary, 1.5 T scanners exhibited larger discrepancies in the measured T<sub>1</sub> compared with the reference values. In addition, 1.5 T scanners displayed less reproducibility in T<sub>1</sub> relaxation time measurements across different 1.5 T scanners, and pulse sequences.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.phmed.2021.100038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41961033","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1016/j.phmed.2021.100042
Manuel Feurhuber , Ralf Neuschwander , Thomas Taupitz , Valentin Schwarz , Carsten Frank , Christoph Hochenauer
Little is known about the steam content in mixtures of steam and NCGs (Non-Condensable Gases), also referred to as steam-air mixtures, required for successful sterilization and about the contribution of additional liquid water in the sterilization chamber to this process. In this study, sterilization efficiency was assessed with Geobacillus stearothermophilus spores in different steam-NCGs mixtures and under different temperatures and holding times. For each experiment, water, air and bioindicators (BIs) were placed in a gas-tight metal box which then underwent one pre-defined sterilization cycle. The initial water amount, sterilization temperatures and holding times were varied. The volume fractions of steam were calculated by applying thermodynamic laws, and the steam distribution was simulated using Computational Fluid Dynamics (CFD). The inactivation of the BIs was represented as a function of different steam-NCG mixtures. The main finding is that the steam volume in the gas phase is of little importance, but the amount of liquid water available to wet BIs during sterilization is crucial. This study represents the first investigation on bacterial inactivation during the sterilization process in different steam-NCG mixtures using different amounts of liquid water. The previously unknown inactivation kinetics results may prove useful for developers and researchers and enhance medical safety.
{"title":"Inactivation kinetics of Geobacillus stearothermophilus spores during the sterilization in steam-NCGs (steam-air) mixtures","authors":"Manuel Feurhuber , Ralf Neuschwander , Thomas Taupitz , Valentin Schwarz , Carsten Frank , Christoph Hochenauer","doi":"10.1016/j.phmed.2021.100042","DOIUrl":"10.1016/j.phmed.2021.100042","url":null,"abstract":"<div><p>Little is known about the steam content in mixtures of steam and NCGs (Non-Condensable Gases), also referred to as steam-air mixtures, required for successful sterilization and about the contribution of additional liquid water in the sterilization chamber to this process. In this study, sterilization efficiency was assessed with <em>Geobacillus stearothermophilus</em> spores in different steam-NCGs mixtures and under different temperatures and holding times. For each experiment, water, air and bioindicators (BIs) were placed in a gas-tight metal box which then underwent one pre-defined sterilization cycle. The initial water amount, sterilization temperatures and holding times were varied. The volume fractions of steam were calculated by applying thermodynamic laws, and the steam distribution was simulated using Computational Fluid Dynamics (CFD). The inactivation of the BIs was represented as a function of different steam-NCG mixtures. The main finding is that the steam volume in the gas phase is of little importance, but the amount of liquid water available to wet BIs during sterilization is crucial. This study represents the first investigation on bacterial inactivation during the sterilization process in different steam-NCG mixtures using different amounts of liquid water. The previously unknown inactivation kinetics results may prove useful for developers and researchers and enhance medical safety.</p></div>","PeriodicalId":37787,"journal":{"name":"Physics in Medicine","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2352451021000081/pdfft?md5=2d1038b5892b41668f2830ad785c02eb&pid=1-s2.0-S2352451021000081-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48019640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}