Ethylene‐vinyl acetate foam as a new lung substitute in radiotherapy

Marqués, Enrique; Mancha, Pedro J.

doi:10.1002/mp.12781

Cited by 5 publications

(3 citation statements)

References 17 publications

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“…Previous research by Marques and Mancha reported the use of PEVA 40% as a foam sheet due to ease of manufacture and design in producing a novel lung replacement in radiotherapy. This copolymer can effectively mimic the dosimetric and physical features of ICRU lung tissue [4].…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Hybrid Pre-Dispersed Organo-Montmorillonite/ Destabilized Bentonite Nanofillers for Improving Tensile Strength of PEVA Copolymer with 40% Vinyl Acetate Composition

Fitri

Osman

Othman

et al. 2020

MSF

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In this work, soft and flexible poly (ethylene-co-vinyl acetate) (PEVA) with 40% vinyl acetate (VA) composition was used as matrix material to form nanocomposites with single nanofiller (organo-montmorillonite (OMMT) or Bentonite (Bent)) and hybrid nanofillers (OMMT+Bent in the ratios of 4:1, 3:2, 2:3 and 1:4). In order to achieve greater exfoliation and dispersion of the hybrid nanofillers in the PEVA matrix, the pre- dispersing and destabilization technique was applied to the O-MMT and Bent, respectively. The procedures were done prior to the melt compounding process of the nanocomposite. A tensile test was done to evaluate the mechanical properties of the resultant nanocomposites and to allow the selection of the best OMMT/Bent ratio for the production of the hybrid nanocomposite. The structure and fractured surfaces of the neat PEVA and nanocomposite were analyzed using Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM), respectively. Results indicated that the addition of hybrid pre-dispersed OMMT/destabilized bentonite nanofillers into the PEVA matrix resulted in greater mechanical performance as compared to the single OMMT or single Bent nanofiller. The best achievement in the tensile strength and elongation at break of the PEVA hybrid nanocomposite was obtained when the hybrid nanofillers was added in the ratio of 4:1 (OMMT: Bent). The SEM analysis showed that the PEVA hybrid nanocomposite with 4OMMT: 1Bent had greater matrix deformation than the neat PEVA when subjected to tensile load. This mechanical deformation could be related to the increased flexibility of the PEVA chains which facilitated more energy absorption during the stretching of the material. Apparently, this mechanism acted as a matrix toughening process which allowed the increment of both tensile strength and elongation at break values of the PEVA upon the addition of the hybrid nanofillers.

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Section: Introductionmentioning

confidence: 99%

Incorporation of Hybrid Pre-Dispersed Organo-Montmorillonite/ Destabilized Bentonite Nanofillers for Improving Tensile Strength of PEVA Copolymer with 40% Vinyl Acetate Composition

Fitri

Osman

Othman

et al. 2020

MSF

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“…Other studies have demonstrated that foams and other urethane‐based materials can closely model lung tissue . However, these lung phantoms were designed to work in CT imaging or radiotherapy dosimetry applications and did not require embedded radioactivity nor the corresponding short construction time needed in SPECT phantoms.…”

Section: Introductionmentioning

confidence: 99%

“…Other studies have demonstrated that foams and other urethane-based materials can closely model lung tissue. [3][4][5][6] However, these lung phantoms were designed to work in CT imaging or radiotherapy dosimetry applications and did not require embedded radioactivity nor the corresponding short construction time needed in SPECT phantoms. The purpose of this work was to create a new lung phantom using expanding polyurethane foam (EPF) that more closely models the density of actual lung tissue and exhibits a more uniform activity distribution than the polystyrene and water-based method.…”

Section: Introductionmentioning

confidence: 99%

Development and testing of SPECT/CT lung phantoms made from expanding polyurethane foam

et al. 2019

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Purpose Currently, single‐photon emission computed tomography (SPECT)/computed tomography (CT) lung phantoms are commonly constructed using polystyrene beads and interstitial radioactive water. However, this approach often results in a phantom with a density (typically −640 HU) that is considerably higher than that of healthy lung (−750 to −850 HU) or diseased lung (−900 to −950 HU). Furthermore, the polystyrene and water phantoms are often quite heterogeneous in both density and activity concentration, especially when reused. This work is devoted to examining methods for creating a more realistic lung phantom for quantitative SPECT/CT using 99mTc‐laced expanding polyurethane foam (EPF). Methods Numerous aspects of EPF utilization were studied, including stoichiometric mixing to control final foam density and the effect of water during growth. We also tested several ways of molding the foam lung phantoms. The most successful method utilized a three‐part silicone mold that allowed for creation of a two‐lobe phantom, with a different density and activity concentration in each lobe. Results The final phantom design allows for a more anatomically accurate geometry as well as customizable density and activity concentration in the different lobes of the lung. We demonstrated final lung phantom densities between −760 and −690 HU in the “healthy” phantom and −930 to −890 HU in the “unhealthy” phantom tissue. On average, we achieved 15% activity concentration nonuniformity and 12% density nonuniformity within a given lobe. Conclusions Final EPF lung phantoms closely matched the densities of both health and diseased lung tissue and had sufficient uniformities in both density and activity concentration for most nuclear medicine applications. Management of component moisture content is critical for phantom reproducibility.

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Simultaneous high‐pitch multi‐energy CT pulmonary angiography using a dual‐source photon‐counting‐detector CT: A phantom experiment

Mihailovic,

Bruesewitz,

Swicklik

et al. 2024

J Applied Clin Med Phys

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PurposeA dual‐source CT system can be operated in a high‐pitch helical mode to provide a temporal resolution of 66 ms, which reduces motion artifacts in CT pulmonary angiography (CTPA). It can also be operated in a multi‐energy (ME) mode to provide iodine maps, beneficial in the evaluation of pulmonary embolism (PE). No energy‐integrating detector (EID) CT can perform simultaneous ME and high‐pitch acquisition. This phantom study aimed to evaluate the ability of a photon‐counting‐detector (PCD) CT to perform simultaneous high‐pitch and ME imaging for CTPA.MethodsA motion phantom was used to mimic the respiratory motion. Two tubes filled with iodine with intravascular thrombus mimicked by injecting glue within the tubes were placed along with 5, 10, and 15 mg/mL iodine samples, on a motion phantom at 20 and 30 revolutions per minute. Separate high‐pitch and ME EID‐CT scans and a single high‐pitch ME PCD scan were acquired and virtual monoenergetic images and iodine maps reconstructed. Percent thrombus occlusion was measured and compared between static and moving images.ResultsWhen there was motion, EID‐CT ME suffered from significant motion artifacts. The measured iodine concentrations with PCD‐CT in high‐pitch ME were more stable when there was a motion, with a lower standard deviation than EID‐CT in ME mode. The estimated percent thrombus occlusion dropped significantly with applied motion on EID‐CT, while PCD‐CT high‐pitch ME mode showed good agreement between measurements on static or moving images.ConclusionPCD‐CT with combined ME and high‐pitch mode facilitates simultaneous accurate iodine quantification and assessment of intravascular occlusion.

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Ethylene‐vinyl acetate foam as a new lung substitute in radiotherapy

Abstract: The EVA40 is an excellent cork-like lung substitute for radiotherapy applications. From a sole material used in footwear, it is possible to obtain a lung substitute that mimics the physical and dosimetric characteristics of ICRU lung tissue even better than the RANDO commercial phantom.

Cited by 5 publications

References 17 publications

Incorporation of Hybrid Pre-Dispersed Organo-Montmorillonite/ Destabilized Bentonite Nanofillers for Improving Tensile Strength of PEVA Copolymer with 40% Vinyl Acetate Composition

Incorporation of Hybrid Pre-Dispersed Organo-Montmorillonite/ Destabilized Bentonite Nanofillers for Improving Tensile Strength of PEVA Copolymer with 40% Vinyl Acetate Composition

Development and testing of SPECT/CT lung phantoms made from expanding polyurethane foam

Simultaneous high‐pitch multi‐energy CT pulmonary angiography using a dual‐source photon‐counting‐detector CT: A phantom experiment

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