Users Manual Part 6

Clinical User’s Guide IBA | 48-1 |
Volume 1 - Treatment Session
Chapter 48
Using the Universal Beam Triggering
• • • • • •
Interface
Introducing Triggering
Why Use Triggering With the Proton Beam?
When treating patients using particle therapy, it is important to deliver a high dose to
a target volume while minimizing the dose to surrounding healthy tissues.
Physiological movements of the patient, such as the patient's respiratory
movements, among others, may cause the target volume to move during irradiation,
which can result in insufficient dose delivery to the target volume and unwanted
dose delivery to surrounding healthy tissues.
A gating system helps to overcome the problem of intrafraction motion in proton
therapy. Beam triggering is the capability to switch the beam On and Off.
Why Use Triggering With the Patient Positioning
Verification System (PPVS)?
The same physiological movements can affect the effectiveness of X-ray images that
are taken during patient alignment for the setup or treatment position.
Prior to beam irradiation, the position of the target volume is verified using a PPVS.
With the X-ray system, X-ray images are taken and compared with a set of reference
radiographs and corrections can be made to the patient's position.
The PPVS can also be sensitive to physiological motions of the patient. To solve this
problem, the PPVS can be enabled/disabled following a triggering signal from a
physiological cycle measuring device.