Editing Isocentric technique (section)

==Working==
The movements of the [[linear particle accelerator]] (or linac) are threefold:
# the [[Gantry crane|gantry]] rotates (like a big crane arm)
# the [[collimator]] twists in the head of the gantry
# the bed swings around on the floor
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All of these movements in the modern linac occur around an axis that runs through the isocenter. In this way, if the centre of the target area in the patient's body is moved to coincide with the [[isocenter]], then all motions of the machine will remain centred on the target. This way, non-target areas will only receive short durations of [[radiation]], reducing damage to them, while the target area receives constant radiation.