Users Manual Part 1

IBA | 3-2 | Clinical User’s Guide
Volume 1 - Treatment Session
|Part I - Explaining Essential Safety Aspects Emergency Procedures in Case of Irradiation Hazard |
A Patient is in the Treatment Room and the
Beam Fails to Stop when Requested
The following situations can be distinguished whereby a patient can be subjected to
a dose higher than requested:
 The preset dose has been reached and the beam fails to shut off automatically
 A Radiation Therapy Technologist (RTT) requests the beam to pause and the
beam fails to pause
 A RTT requests the beam to stop and the beam fails to stop
The Preset Dose Has Been Reached and the Beam Fails
to Shut off Automatically
The normal end to a treatment is triggered by the dose count from ionization
chamber 2 (IC2) to the Therapy Control System (TCS). The irradiation normally stops
when the dose read by IC2 equals the required dose.
In the PBS beam delivery technique the setpoint of each magnet is progressively
modified for each map (i.e., each layer) to reach the setpoint of the first spot to
irradiate; that setpoint is kept constant until the spot is fully irradiated and then it is
adapted to reach the setpoint for the next spot, until the last spot is irradiated. All the
setpoints are calculated by Scanalgo and are then applied by the scanning controller.
If treatment is not intended to be resumed, a RTT also has the option to stop an
irradiation by clicking Pause followed by Stop from the I
RRADIATION SCREEN.
A Radiation Therapy Technologist (RTT) Requests the
Beam to Pause (or Stop) and the Beam Fails to Pause (or
Stop)
A pause interrupts the beam and prevents it from entering the TR.
If, as a RTT, you interrupt the irradiation from the TCR by clicking Pause from the
I
RRADIATION SCREEN and the irradiation does not pause, immediately perform the
procedure that follows.
Irradiation Emergency Procedure
If the beam does not pause (or stop):
 when the preset dose count has been reached
 when the user requires it