View in EDS HTML Full Text PDF Full Text

Assessment of thermochromic phantoms for characterizing microwave ablation devices.

Saved in:
Bibliographic Details
Title: Assessment of thermochromic phantoms for characterizing microwave ablation devices.
Authors: Zia, Ghina1 (AUTHOR), Lintz, Amber1 (AUTHOR), Hardin, Clay1 (AUTHOR), Bottiglieri, Anna1 (AUTHOR), Sebek, Jan1 (AUTHOR), Prakash, Punit1 (AUTHOR) prakashp@ksu.edu
Source: Medical Physics. Nov2024, Vol. 51 Issue 11, p8442-8453. 12p.
Subjects: Dielectric measurements, Colorimetric analysis, Permittivity, Microwave devices, Microwave antennas
Abstract: Background and purpose: Thermochromic gel phantoms provide a controlled medium for visual assessment of thermal ablation device performance. However, there are limited studies reporting on the comparative assessment of ablation profiles assessed in thermochromic gel phantoms against those in ex vivo tissue. The objective of this study was to compare microwave ablation zones in a thermochromic tissue‐mimicking gel phantom and ex vivo bovine liver and to report on measurements of the temperature‐dependent dielectric and thermal properties of the phantom. Methods: Thermochromic polyacrylamide phantoms were fabricated following a previously reported protocol. Phantom samples were heated to temperatures in the range of 20°C–90°C in a temperature‐controlled water bath, and colorimetric analysis of images of the phantom taken after heating was used to develop a calibration between color changes and the temperature to which the phantom was heated. Using a custom, 2.45 GHz water‐cooled microwave ablation antenna, ablations were performed in fresh ex vivo liver and phantoms using 65 W applied for 5 min or 10 min (n = 3 samples in each medium for each power/time combination). Broadband (500 MHz–6 GHz) temperature‐dependent dielectric and thermal properties of the phantom were measured over the temperature range of 22°C–100°C. Results: Colorimetric analysis showed that the sharp change in gel phantom color commences at a temperature of 57°C. Short and long axes of the ablation zone in the phantom (as assessed by the 57°C isotherm) for 65 W, 5 min ablations were aligned with the extents of the ablation zone observed in ex vivo bovine liver. However, for the 65 W, 10 min setting, ablations in the phantom were on average 23.7% smaller in the short axis and 7.4 % smaller in the long axis than those observed in ex vivo liver. Measurements of the temperature‐dependent relative permittivity, thermal conductivity, and volumetric heat capacity of the phantom largely followed similar trends to published values for ex vivo liver tissue. Conclusion: Thermochromic tissue‐mimicking phantoms provides a controlled, and reproducible medium for comparative assessment of microwave ablation devices and energy delivery settings. However, ablation zone size and shapes in the thermochromic phantom do not accurately represent ablation sizes and shapes observed in ex vivo liver tissue for high energy delivery treatments (65 W, 10 min). One cause for this limitation is the difference in temperature‐dependent thermal and dielectric properties of the thermochromic phantom compared to ex vivo bovine liver tissue, as reported in the present study. [ABSTRACT FROM AUTHOR]
Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Full text is not displayed to guests.
FullText Links:
  – Type: pdflink
Text:
  Availability: 1
Header DbId: egs
DbLabel: Engineering Source
An: 180622954
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Assessment of thermochromic phantoms for characterizing microwave ablation devices.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Zia%2C+Ghina%22">Zia, Ghina</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Lintz%2C+Amber%22">Lintz, Amber</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Hardin%2C+Clay%22">Hardin, Clay</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Bottiglieri%2C+Anna%22">Bottiglieri, Anna</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Sebek%2C+Jan%22">Sebek, Jan</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Prakash%2C+Punit%22">Prakash, Punit</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> prakashp@ksu.edu</i>
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Medical+Physics%22">Medical Physics</searchLink>. Nov2024, Vol. 51 Issue 11, p8442-8453. 12p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Dielectric+measurements%22">Dielectric measurements</searchLink><br /><searchLink fieldCode="DE" term="%22Colorimetric+analysis%22">Colorimetric analysis</searchLink><br /><searchLink fieldCode="DE" term="%22Permittivity%22">Permittivity</searchLink><br /><searchLink fieldCode="DE" term="%22Microwave+devices%22">Microwave devices</searchLink><br /><searchLink fieldCode="DE" term="%22Microwave+antennas%22">Microwave antennas</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Background and purpose: Thermochromic gel phantoms provide a controlled medium for visual assessment of thermal ablation device performance. However, there are limited studies reporting on the comparative assessment of ablation profiles assessed in thermochromic gel phantoms against those in ex vivo tissue. The objective of this study was to compare microwave ablation zones in a thermochromic tissue‐mimicking gel phantom and ex vivo bovine liver and to report on measurements of the temperature‐dependent dielectric and thermal properties of the phantom. Methods: Thermochromic polyacrylamide phantoms were fabricated following a previously reported protocol. Phantom samples were heated to temperatures in the range of 20°C–90°C in a temperature‐controlled water bath, and colorimetric analysis of images of the phantom taken after heating was used to develop a calibration between color changes and the temperature to which the phantom was heated. Using a custom, 2.45 GHz water‐cooled microwave ablation antenna, ablations were performed in fresh ex vivo liver and phantoms using 65 W applied for 5 min or 10 min (n = 3 samples in each medium for each power/time combination). Broadband (500 MHz–6 GHz) temperature‐dependent dielectric and thermal properties of the phantom were measured over the temperature range of 22°C–100°C. Results: Colorimetric analysis showed that the sharp change in gel phantom color commences at a temperature of 57°C. Short and long axes of the ablation zone in the phantom (as assessed by the 57°C isotherm) for 65 W, 5 min ablations were aligned with the extents of the ablation zone observed in ex vivo bovine liver. However, for the 65 W, 10 min setting, ablations in the phantom were on average 23.7% smaller in the short axis and 7.4 % smaller in the long axis than those observed in ex vivo liver. Measurements of the temperature‐dependent relative permittivity, thermal conductivity, and volumetric heat capacity of the phantom largely followed similar trends to published values for ex vivo liver tissue. Conclusion: Thermochromic tissue‐mimicking phantoms provides a controlled, and reproducible medium for comparative assessment of microwave ablation devices and energy delivery settings. However, ablation zone size and shapes in the thermochromic phantom do not accurately represent ablation sizes and shapes observed in ex vivo liver tissue for high energy delivery treatments (65 W, 10 min). One cause for this limitation is the difference in temperature‐dependent thermal and dielectric properties of the thermochromic phantom compared to ex vivo bovine liver tissue, as reported in the present study. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>Copyright of Medical Physics is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=180622954
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1002/mp.17404
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 12
        StartPage: 8442
    Subjects:
      – SubjectFull: Dielectric measurements
        Type: general
      – SubjectFull: Colorimetric analysis
        Type: general
      – SubjectFull: Permittivity
        Type: general
      – SubjectFull: Microwave devices
        Type: general
      – SubjectFull: Microwave antennas
        Type: general
    Titles:
      – TitleFull: Assessment of thermochromic phantoms for characterizing microwave ablation devices.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Zia, Ghina
      – PersonEntity:
          Name:
            NameFull: Lintz, Amber
      – PersonEntity:
          Name:
            NameFull: Hardin, Clay
      – PersonEntity:
          Name:
            NameFull: Bottiglieri, Anna
      – PersonEntity:
          Name:
            NameFull: Sebek, Jan
      – PersonEntity:
          Name:
            NameFull: Prakash, Punit
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 11
              Text: Nov2024
              Type: published
              Y: 2024
          Identifiers:
            – Type: issn-print
              Value: 00942405
          Numbering:
            – Type: volume
              Value: 51
            – Type: issue
              Value: 11
          Titles:
            – TitleFull: Medical Physics
              Type: main
ResultId 1