Users Manual Part 2

Clinical User’s Guide
IBA | 22-3|
Volume 1 - Treatment Session
|Part III
- The Pencil Beam Scanning (PBS) Suite PBS Multiple Repainting
|
In-Layers Repainting
From the distal to the proximal edge of the target volume, each defined layer is
scanned by the proton beam (or painted) as many times as prescribed until the total
dose prescribed for that layer is delivered. A different number of re-paintings may be
prescribed for each layer in the plan.
The PTS software divides the total dose to be delivered to each spot within a given
layer by the number of re-paintings requested for that layer. If the dose to be
delivered to a given spot in one re-painting falls below a threshold (close to 0.05MU),
the number of re-paintings for that spot decreases to the greatest number such that
the dose for each re-painting is above the threshold. As such, different spots within
the same layer may be re-painted a different number of times.
Only when all the spots within a given layer have received their full dose, the
scanning process progresses on to the next layer.
Identification
This repainting type is labelled PBS-IL in the (Delivery) Technique fields on the
adaPTprescribe and adaPTdeliver screens.
Representation
This repainting type is represented by an icon on adaPTdeliver screens.
Figure 22-3. In-Layers Icon