Treating the head and neck – Radiotherapy and its physics (3/15)


The patient is brought
into the treatment room and the procedure explained. We’ll then get the patient onto the bed in the same position as they were
in the mould room and the simulator, so that they’re in exactly the same
position for treatment. Once he’s on the bed,
we’ll position his cast on him in the same position as he was
in the mould room, and in the simulator afterwards, so he’ll already know how that feels. Once he’s comfortable and settled, we’ll dim the machine lights
in the room and move the bed up
and towards the isocentre. Using the marks previously put
onto the cast in the simulator, we will line up the lights and the lasers
in the treatment room to the correct treatment position
which we call the isocentre. Once everything’s set up and we’re happy everything’s
in the correct position, we will verbally check all the parameters
for the treatment before leaving the treatment room. OK, we’ve got a gantry of 270,
columnator of 81, which is wedged thick end ante. The radiographers will then leave
the patient in the treatment room and go outside to turn the machine on to
give the treatment. While the patient is having
their treatment, they will always be watching
and listening to them, via the close circuit television system, so that if the patient has a problem, we
can immediately turn the machine off. OK, that’s lovely. The duration of a treatment is monitored
outside in the control area, by reviewing the monitor units appearing
on the screen. A monitor unit relates to
a calibrated unit of radiation. One monitor unit corresponds to a dose of one centigray
under reference conditions.