Post

Evaluation of Thermal Effects from Medical Devices on Human Tissue (DRAFT)

This guidance focuses on evaluating thermal effects of medical devices that produce tissue temperature changes (heating and/or cooling) as either an intended or unintended consequence of device use. This includes devices that: - Deliver radiofrequency, microwave, light, or other electromagnetic energy - Deliver ultrasound - Use electroporation - Produce temperature changes through contact - Have electrical components that can heat surrounding tissue

This is a draft guidance. Not for implementation.

  1. Determine appropriate testing methodology based on device characteristics and intended use
  2. Conduct verification testing of device parameters before thermal effects assessment
  3. Perform experimental assessment using appropriate model (phantom, ex vivo, in vivo)
  4. Document temperature-time history and dimensions of thermally affected tissue
  5. Validate any computational models used for evaluation
  6. Consider need for clinical testing if non-clinical results insufficient
  7. Develop comprehensive labeling with thermal effect dimensions and parameters
  8. Submit Pre-Submission to FDA for feedback on testing approach if needed
  9. Ensure testing covers full range of device specifications and use conditions
  10. Document scientific rationale for chosen testing methods and acceptance criteria

Key Considerations

Clinical testing

  • Clinical data may be needed when non-clinical and animal studies are insufficient
  • Studies should test full range of device parameters in intended population
  • Must include safety measures and monitoring of target/non-target organs
  • Results should document thermal injury and temperature-time history

Non-clinical testing

  • Verification of device parameters through bench testing required
  • Testing should cover full range of specifications with predefined acceptance criteria
  • Must be done before assessment of tissue effects
  • Deviations from acceptance criteria need scientific rationale

Labelling

  • Include chart/graph showing dimensions of thermally affected tissue region
  • Show relationship between power settings, activation duration and tissue types
  • Document expected damage to facilitate safe use

Safety

  • Assessment of tissue effects and thermal energy spread required
  • Testing should evaluate minimum, average and worst-case temperature-time history
  • Must allow tissue to return to baseline temperature
  • Consider immediate and long-term tissue effects

Other considerations

  • IEC 60601-2-33 Ed.4.0: Medical electrical equipment - Part 2-33: Particular requirements for the basic safety and essential performance of magnetic resonance equipment for medical diagnosis

Original guidance

  • Evaluation of Thermal Effects from Medical Devices on Human Tissue
  • HTML / PDF
  • Issue date: 2024-03-15
  • Last changed date: 2024-03-14
  • Status: DRAFT
  • Official FDA topics: Medical Devices
  • ReguVirta summary file ID: 2b870935558abdd30d61656187799d4c
This post is licensed under CC BY 4.0 by the author.