Radiation therapy can be a very effective way to treat cancer – tumour are zapped with a very accurate and very sharp beam of radiation. However, despite the machines being incredibly precise, the treatment might be compromised by the patient’s movement. Now scientists from the University of Birmingham demonstrated that it is possible to safely help patient not breathe for multiple four-minute periods during treatment.
Radiation treatment is very effective, but only if the patient manages to stay very calm. Excessive movement reduces the accuracy and damages healthy surrounding tissue. Image credit: Wikimedia (CC BY-SA 3.0)
When tumours are in the chest, radiation therapy is simply not very accurate due to the person moving too much. Although humans can hold their breath for a while without much of a problem, therapy sessions last for quite a while. No one can hold their breath for the entire duration of the radiotherapy session. Unless they are provided with some help – scientists showed that increasing oxygen levels in the lungs and removing carbon dioxide from blood helps patients hold their breath for longer, making treatment more precise.
When you are laying down and breathing normally, you chest and abdomen can lift by up to 4cm every time you are inhaling. This is a problem when it comes to radiation therapy, because more of the healthy tissue gets in the way of the radiation beam. The tumour has to be attacked several times from different angles and that requires a significant amount of time when the patient should not be breathing. Usually people have no issue holding their breath for 30-60 seconds, but there really is no reason why they shouldn’t be able to stop breathing for up to 5 minutes. We just need to help them a little.
Scientists invited 30 volunteers to breathe oxygen-enriched air for several minutes. This increased the level of oxygen in their lungs and lowered the blood carbon dioxide level in their blood. This allowed participants to hold their breath for about 6 minutes without much problem. With practice they were able to do multiple four-minute periods of holding their breath with breaks for hyperventilation. In other words, patients can safely breath-hold for a total of about 13 minutes (3 breath-holds) within a treatment session lasting just under 20 minutes or for about 41 minutes (9 breath-holds) within a 65 minute session.
Scientists say that this is both possible and safe. In fact, it is much better than what is being done now. By holding their breath patients could make the treatment a little more accurate and safer for the healthy tissues. The most important finding is that it is safe and medical professionals can go ahead and start using this method.
Source: University of Birmingham