Breathing air in (inhale) or out (exhale), and then holding your breath (breath hold) can help keep internal anatomy in the same position. This limits radiation to normal tissue and thereby minimises side effects from radiation therapy. This is particularly beneficial for patients receiving treatment to the chest or abdomen region.

ARO has a simple yet sophisticated system to help patients achieve dependable breath hold.

Patients breathe through a snorkel like device which is connected to a computer. The device/computer system is called the Active Breathing Coordinator (ABC) and helps patients hold their breath.  If at any time patients wish to breathe normally they can release a control button and the ABC system allows air to travel through the snorkel.  The ABC system prevents treatment being delivered if the patient is not in the required breath hold state.

In more detail

Assisted breath hold techniques:

  • Move structures away from (or into) the treatment area 
  • Reduce radiation volumes and margins allowing higher doses to be delivered with less risk to the health of normal tissue.


Assisted Breath hold (inhale) is often used for patients receiving treatment to the left breast or chest wall to reduce dose to the heart.  It has also been used for lung lesions that are close to other organs at risk, too small to see with normal breathing, or if the target moves too much.
Assisted Breath hold (exhale) has been used when treating the liver and pancreas.

See below documents for specific instructions