SURGICAL SIMULATIONS: IT

1
SURGICAL SIMULATIONS ITS ALL IN A GAME !
Gaming techniques for medical
applications. V. Kotamraju, S. Payandeh,
J. Dill Experimental Robotics Laboratory, Simon
Fraser University.
ABSTRACT
THE GRAPHICS PIPELINE
Computer games have come a long way since A.S.
Douglas' Tic-Tac-Toe in 1952, evolving into a
well-understood set of methods, including recent
developments in realism and immersiveness for
game scenarios. Surgical Simulation, on the
other hand, has barely a decade of technological
development. Surgical techniques have evolved
from direct hands-on maneuvers to indirect
minimal-access procedures like Laparoscopy,
involving video cameras to show the surgeon the
instruments and operating site. Learning these
techniques is difficult, but recent advances in
computer technology have allowed development of
virtual training environments to help the
surgeon-to-be. The common component of virtual
reality provides an opportunity to apply game
programming ideas to such training environments.
This poster outlines key techniques in 3D game
applications that can enhance current surgical
simulation technology.
Visibility determination clipping, culling,
occlusion testing.
SURGICAL SIMULATION FRAMEWORK Deformable
modeling. Collision detection and
response. Visual and haptic feedback.
pipeline
Resolution determination LOD analysis.
parallels
Transformation and lighting
Abstract
Rasterization
PERFORMANCE TUNING Analysis Profiling,
bottlenecks (time, memory). Uniprocessor
Hierarchical structures. Multiprocessors
Parallel processing.
Communication bottleneck. Graphics
Processing Unit, Parallel Processing Unit.


GEOMETRICAL TECHNIQUES Collision
detection. Point-inclusion, ray
intersection, convex hull. Sweep and
prune Variants for multiple-object
collisions. Triangle reduction Vertex or
edge collapse.
Progressive mesh.
Selection of LOD.
Load-time tuning of hardware.
USER INPUT Hardware dependency.
Keyboard, mouse. Haptics 6 DOF, force and
torque feedback. Organ-force
response to users.
function-parallel

VIRTUAL REALITY
PARTICLE
SYSTEMS Dynamic, time-dependent, unconnected
mass points. Particles originate, move
and die. Stochastic modeling used to control
particles. Velocity based on blood-vessel
properties. Particle motion influenced by
force-field. Simulation of blood-flow and
blood-clot.
DESIGN PATTERNS Abstract systems of
interaction. Between classes, objects, and
communication flow. Use object-oriented
programming. Provide model reusability.
Programming patterns Spatial index, factory,
singleton. Usability patterns State, focus,
progress.
update
control interaction
real-time data
render
computation and display
SURGICAL SIMULATIONS
GAME PROGRAMMING

TEXTURE MAPPING Wraps image on surface
model. Provides data or patient-specific
view. Adds realism.
3D texture arrays contain original
data. Dynamic
local 2D arrays contain visible
surface data.
ARTIFICIAL INTELLIGENCE Finite State
Machines Analyze surgical motions. Path
Planning Guide trajectory of tool. Fuzzy
logic Measure surgical competence.


NETWORK PROGRAMMING Client-server and
multi-player systems. Remote surgical
training. High performance computing
systems. High-speed networks, Grids.

LEVEL OF DETAIL Scene described at
multiple resolutions. Discrete
(pre-computed) or continuous (on-the-fly).
Fast and realistic rendering. Efficient GPU
utilization. Popping may occur, unsuitable
for single, large models.
SHADING Illumination (light and shadows).
Adds visual details. Components
Ambient, diffuse, specular. Per-vertex or
per-pixel. Phong model Vertex-normal
interpolation for face.
For curved surfaces. Light mapping Light
effects on base texture.
SUMMARY
Several computer game development techniques can
be adapted for surgical simulation. The choice
and implementation of a technique must be based
on application requirements.

Images reproduced from existing
publications. References provided as
handout. vkotamra_at_sfu.ca shahram_at_sfu.ca
dill_at_cs.sfu.ca