Thermal simulation

As an extension of electromagnetic (EM) simulations, thermal simulations provide

  • Precise calculation of hot spots of implants and instruments
  • Advanced calculations of bioheat effects in humans
  • Advanced calculations of bioheat effects in animals

Precise calculation of hot spots of implants and instruments

The thermal solver, processed as an extention of EM simulations, is a powerful tool which provides a full calculation of the temperature distribution surrounding the implant. By performing thermal simulations, the temperature increase over time can be calculated and the location of maximum temperature hot spot at any observation time can be rigorously estimated.

Hotspot calculation 210 s    Hotspot calculation 330 s Hot spot in space domain

Time = 210 s  Time = 330 s      Observation of a hot spot in the space domain describes temperature                                                   variation in mm

Bioheat effects in humans: Thermal simulations in a human model

Thermal simulation

In order to calculate the temperature distribution inside the body tissues, a human model characterized by body size, age and gender can be simulated. In reality, a living human body generates blood flow, which removes some of the energy from the body and therefore may change temperature distribution.

Such a bio-heat effect can be considered by completing the thermal simulation for the human model with a bio-heat transfer mechanism and including the metabolism rate and the blood flow formulations. This will provide a more realistic in vivo estimation.

The simulation of the human model is performed with the goal of comparing the temperature measurement of the metrological setup with the temperature increase in the human tissues, which is recommended both in the standards ISO/TS 10974:2012 (for active implantable medical devices (AIMD)) and ASTM F2182-11a (for non-active medical devices).

Thermal simulations in human Duke model of the Virtual Family (Gosselin et al 2014 Phys. Med. Biol. 59 5287, Christ et al 2010 Phys. Med. Biol. 55 N23)

Bioheat effects in animals

An animal model provides synchronization between a numerical simulation and in-vivo experimental tests. The numerical simulation of an animal model inside the coil can be compared to the measurement of the animal under test.

SAR and temperature distribution of particular animal models inside an MRI coil can be calculated as a reference of in-vivo experiments.

Animal_model

Animal model (Antonio Orlandi, University of L'Aquila (http://orlandi.ing.univaq.it))