Immobilization Using Dental Material Casts Facilitates Accurate Serial and Multimodality Small Animal Imaging

Area of Science:

• Biomedical Imaging
• Materials Science

Background:

• Reproducible patient positioning is crucial for accurate radiation therapy and imaging.
• Small-animal imaging often lacks effective immobilization, hindering serial and multimodality analysis.
• Existing methods may not provide the necessary precision for small subjects.

Purpose of the Study:

• To evaluate vinyl polysiloxane dental impression material as a cost-effective immobilization solution for mice in imaging.
• To assess potential imaging artifacts introduced by the dental material.
• To determine the material's suitability for integrating fiducial markers for enhanced image registration.

Main Methods:

• Four types of vinyl polysiloxane dental impression materials were tested.
• Magnetic resonance imaging (MRI) at 4.7 T was used to detect artifacts in a water phantom within the cast.
• Electron paramagnetic resonance (EPR) imaging at 9 mT was employed to assess signal interference.
• Fiducial markers were embedded within the dental molds.

Main Results:

• MRI showed no significant artifacts in the center of the images; effects near the coil ends were negligible.
• EPR imaging detected no signal from the dental impression materials.
• The material allowed for secure embedding of fiducial markers, facilitating image registration.

Conclusions:

• Vinyl polysiloxane dental impression material is a suitable, artifact-free medium for immobilizing mice in imaging.
• This method enhances the reproducibility of small-animal positioning.
• The integration of fiducials simplifies image registration, improving the analysis of serial and multimodality imaging data.