Users Manual Part 6
Clinical User’s Guide
IBA | 46-5|
Volume 1 - Treatment Session
|Part XI
- Patient Positioning and Alignment Introducing Patient Positioning and Alignment
|
Prescribed and Corrected Setup Position
The relationship between the prescribed Setup position and the required Setup
position evolves as follows:
With the patient on the couch or chair, the RTT will verify and finely adjust
(correct) the Setup position and then save it. Until the first beam tuning request
is made, the RTT may perform as many positioning and adjusting iterations as
necessary and then save the results. The difference between the Prescribed and
the Corrected Setup positions will be propagated to the treatment beams.
Treatment Position
While the Setup position is specific to the setup beam, a Treatment position is
specific to a treatment beam. The configuration of the Treatment position orients the
treatment site (tumor) to receive the beam.
The Treatment position is a labeled position; you must perform an Auto or Manual
motion to bring the Patient Positioning Devices (PPDs) to this Treatment position.
To ensure an acceptable patient setup timeline, small adjustments in the beam
direction/position relative to the patient must be accomplished without large changes
in patient positioning setup. Small adjustments in beam angle normal to the plane of
rotation of the nozzle cannot be accomplished by small changes in the available
translation and rotation variables. Maintaining the accuracy of the original setup point
in this case will be achieved by including pitch and roll degrees of freedom with small
dynamic range.
Couch pitch and roll articulations permit the fine adjustment of patient position with
respect to the horizontal plane.
Important The change of couch position involving pitch and/or roll rotation may
involve a translation along the Z-axis. This is normal behavior of the
Patient Positioning System (PPS).
Couch movements are expressed in the IEC Table Top coordinate
system; these movements are performed following the International
Standard IEC 61217, Ed2.0, 2011-12, Radiotherapy Equipment -
Coordinates, Movement, and Scales.
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