Improved assessment of radiofrequency electromagnetic field power deposition near orthopaedic device using a bone-inclusive ASTM phantom under 1.5T and 3T MRI.

Physics in medicine and biology · 2024 · Unclear · Low evidence

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UnclearLow evidencePaper 5841

Study snapshot

PublicationPhysics in medicine and biology · 2024

Study typeengineering

Reported directionUnclear

Evidence ratingLow

Abstract

A bone-inclusive ASTM phantom is proposed to improve the assessment of radiofrequency electromagnetic field (RF-EMF) power deposition near orthopedic device under 1.5 T and 3 T magnetic resonance imaging (MRI).A phantom is created by introducing a cylindrical bone structure inside the American Society for Testing and Materials (ASTM) phantom. Four orthopaedic implant families-rod, nailing system, plate system, and hip replacement-are used in the study. RF-EMF power deposition (in terms of peak averaged specific absorption rate over 1 gram) near these implants are evaluated by placing these implants inside the standard ASTM phantom, the developed bone-inclusive ASTM phantom, and two anatomically representative human body phantoms, known as Duke and Ella. Numerical simulations are performed to calculate the RF-EMF power deposition near various orthopaedic devices within these phantoms.For devices implanted inside or near bone tissue, the evaluation of RF-EMF power deposition using the developed bone-inclusive ASTM phantom shows better correlations to the human body phantoms than the ASTM phantom. This improvement is attributed to the portion of the devices implanted within the bone tissue.The bone-inclusive ASTM phantom has the different tissue of interests surrounding the implants compared to the ASTM phantom. This variation can lead to the different resonance frequency under RF-EMF exposure. This leads to better correlation of RF-EMF power deposition near orthopaedic implants inside human body, making the bone-inclusive ASTM phantom more suitable for evaluating RF-EMF power deposition than ASTM phantom in MRI scans.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeengineering

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureRF

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Numerical simulations compared peak 1 g-averaged SAR near several orthopaedic implant families across a standard ASTM phantom, a proposed bone-inclusive ASTM phantom, and two anatomically representative human body phantoms (Duke and Ella) under 1.5 T and 3 T MRI. For devices implanted inside or near bone tissue, the bone-inclusive ASTM phantom showed better correlation to the human body phantoms than the standard ASTM phantom, and was described as more suitable for evaluating RF-EMF power deposition near orthopaedic implants in MRI scans.

Outcomes measured

RF-EMF power deposition near orthopaedic implants (peak averaged SAR over 1 g)
Correlation of phantom-based SAR estimates with anatomically representative human body phantoms (Duke, Ella)

Limitations

Study is based on numerical simulations (no experimental validation described in abstract).
Only specific implant families and phantom models (ASTM, bone-inclusive ASTM, Duke, Ella) are evaluated; generalizability to other devices/phantoms not stated.
MRI field strengths are limited to 1.5 T and 3 T; RF frequencies not reported in abstract.

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": "RF",
    "source": "MRI",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "RF-EMF power deposition near orthopaedic implants (peak averaged SAR over 1 g)",
    "Correlation of phantom-based SAR estimates with anatomically representative human body phantoms (Duke, Ella)"
  ],
  "main_findings": "Numerical simulations compared peak 1 g-averaged SAR near several orthopaedic implant families across a standard ASTM phantom, a proposed bone-inclusive ASTM phantom, and two anatomically representative human body phantoms (Duke and Ella) under 1.5 T and 3 T MRI. For devices implanted inside or near bone tissue, the bone-inclusive ASTM phantom showed better correlation to the human body phantoms than the standard ASTM phantom, and was described as more suitable for evaluating RF-EMF power deposition near orthopaedic implants in MRI scans.",
  "effect_direction": "unclear",
  "limitations": [
    "Study is based on numerical simulations (no experimental validation described in abstract).",
    "Only specific implant families and phantom models (ASTM, bone-inclusive ASTM, Duke, Ella) are evaluated; generalizability to other devices/phantoms not stated.",
    "MRI field strengths are limited to 1.5 T and 3 T; RF frequencies not reported in abstract."
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "MRI",
    "radiofrequency electromagnetic field",
    "RF-EMF",
    "specific absorption rate",
    "SAR",
    "ASTM phantom",
    "bone-inclusive phantom",
    "orthopaedic implants",
    "rod",
    "nailing system",
    "plate system",
    "hip replacement",
    "numerical simulation",
    "1.5T",
    "3T"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.2,
      "reason": "MRI-related RF exposure assessment context; no specific occupational population stated."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1088/1361-6560/ad6953
PubMed: 39079547

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