Study type: Technical/dosimetric study (experimental study)

MRI monitoring of interstitial microwave-induced heating and thermal lesions in rabbit brain in vivo tech./dosim.

By: Moriarty JA, Chen JC, Purcell CM, Ang LC, Hinks RS, Peters RD, Henkelman RM, Plewes DB, Bronskill MJ, Kucharczyk W
Published in: J Magn Reson Imaging 1998; 8 (1): 128-135
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Aim of study (acc. to author)

To use MRI to monitor microwave heating and thermal damage induced by an interstitial microwave antenna in an in vivo animal model.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 915 MHz
Exposure duration: 400 sec
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General information

Microwave antenna was impanted in the brain in order to cause local heating. Power was 30 to 100 W ('Power density' and '65' 'W/cm²' (see above) entered because correct input type not supported by dialog mask). Due to power loss through the conduction pas

Exposure 1

Main characteristics
Frequency 915 MHz
Type
Waveform
Exposure duration 400 sec
Exposure setup
Exposure source
  • helix (length 12 mm; diameter 1mm)
Distance between exposed object and exposure source 0 m
Setup Antenna was inserted into the cerebral hemisphere through the first burrhole.
Additional info the head of the animal were immobilized in an MR compatible acrylic frame and three burrholes (2.5 mm) were drilled.
Parameters

No parameters are specified for this exposure.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

MRI can be accomplished during interstitial microwave heating with minimal image degradation from the in situ antenna. Near-real-time temperature-related signal changes can be observed on the MR images. The phase changes correlate closely with local tissue temperature modifications. Given these attributes of MRI to monitor temperature changes within a target volume, further development of this technique may improve control of thermal ablation. Accurate data concerning the thermal dose-response curve is still required and is not available from the current pilot study.

Study character:

Study funded by