Wii Transrectal Ultrasound Simulator

 

Background/Problem

Transrectal ultrasound is invasive and poses a challenge to training using live models. Virtual reality (VR) models can provide objective learning data and feedback, and further relieve concerns of subject discomfort or injury during training.
We have developed a high-fidelity, low-cost prototype VR simulator intended to train the skills necessary in order to perform transrectal Ultrasonography (TRUS) of the prostate.

Approach

Actual ultrasound images have been acquired in the sagittal and axial views, and then registered in virtual space. We use several infrared and accelerometer sensors in a commercial gaming interface, the Wii set, to track motions for each degree of freedom (DoF).
One programmable Wii remote is mounted on a dummy probe, and the second is deployed laterally to the probe. The simulation software program reads and translates the outputs of the tracking sensors, calculates the orientation of the hand-held probe, registers its scanning plane with the pre-built ultrasound data model, processes and manipulates the pixels on the plane, and accordingly updates the images on the monitor as the final visual output.
A rubber rectum with lubrication serves to provide the appropriate force-feedback. Wii buttons are utilized to simulate ultrasound transducer probe features.

Results/Conclusions

Using the Wii interface, integrated with our virtual TRUS software, we have built a high-fidelity basic simulator with force-feedback for transrectal ultrasound. Currently, a limitation exists if the scanning plane of probe is manipulated out of the volume of the virtual model, with only part of the ultrasound image being represented. The creation of a curriculum along with the capability for more complex procedures such as biopsy that require model deformation and penetration will transform this simulator into a robust trainer worthy of clinical validation studies.

Team Members:

• Dr. Rob Sweet
• Dr. Pat Fulgham MD
• Dr. Sijo Parekattil MD
• Dr. Yunhe Shen
• Dr. Ravi Chitvala
• Dan Burke

Project View

Ultrasound Data

Wiimote

Prototype