Users Manual Part 1

IBA | 7-6 | Clinical User’s Guide
Volume 1 - Treatment Session
|Part II - Using Treatment Room Equipment Moving the Patient Positioning Devices |
Constant Weight on the Couch
Couch Modifications
To ensure good accuracy and collision detection, it is required to identify the mass
installed above the PPS coupling System, and the position of the center of gravity of
this mass.
Each couch is identified by a unique couch ID and the mass properties of each couch
are configured in the IBA system according to the couch ID. The patient mass
properties are measured and updated automatically by the PPS before each motion,
except for the patient Z-coordinate which is based on an assumption.
Extended Treatment Volume (ETV)
The extended treatment volume, in the case of a PPS with a couch, is a box-shaped
virtual volume attached to the table top. Its inferior surface is merged with the
horizontal top surface of the couch. The longitudinal axis of the ETV is parallel to the
longitudinal axis of the couch and intercepts orthogonally rotation axis of joint 6 of
the PPS.
This volume includes all the points that can be physically brought to the isocenter
with:
 a PPS top rotation within the interval [-95°; +95°]
 a PPS pitch value between -5° and 5°
 and a PPS roll value between 5° and -5°
CAUTION The same clinical devices must be put on the Patient Positioning
System (PPS) for every treatment day in order to maintain a constant
weight on the couch.
WARNING Define a new couch ID and related couch properties when mass
properties of the couch are changed significantly. Failure to do so may
result in an incorrect couch properties assumption.
Examples of significant changes are an unknown couch, a modified
couch, or a couch loaded with clinical equipment above 15 kg.