Truth Cube

Establishing Physical Standards for Real Time Soft Tissue Simulation

Division of Engineering and Applied Sciences, Biorobotics Laboratory, Harvard University
CIMIT Simulations Group, Massachusetts General Hospital
Support provided by Unites States Army Medical Research and Material Command

Motivation:

Similar to how real-time flight simulators changed the way pilots learned how to safely fly and brought aviation to a new level, real-time surgical simulators are being developed that will change the way surgeons train and plan for minimally invasive surgeries. There are well characterized man-made materials used to validate the accuracy and predictability of the flight simulators. There are no such standards for biological soft tissues. Currently real-time modeling is at best validated against FEM models that have their own intrinsic limitations. This site is dedicated to an ongoing study to develop physical standards resulting in a database of relevant information used to validate real-time tissue deformation.
 

What you'll find on this site:


 

Truth Cube 

 In this proof of concept study, a simple 8x8x8 cm3 of silicone rubber with an exact pattern of embedded Teflon beads was tested under controlled loading conditions while CT images were taken. The known material properties, geometry, and carefully controlled boundary conditions resulted in a complete set of volumetric displacement data. Uniaxial compression and spherical indentation test results are listed.

Accurate Organ 

 In round 2, we hope to similarly test a whole organ (porcine liver) that has embedded CT fiducials to provide volumetric displacement data. Initial concept data presented.

Rubber Liver 

 Lastly, we hope to modify our truth cube by incorporating the same techniques but using a more complex and appropriate geometry (i.e. a liver model). The complex geometry will bring the "cube" beyond the useful limits of FEM analysis for real time modeling. This together with the models known material properties and controlled boundary conditions will provide a valuable physical standard to real time soft tissue simulations.