Researchers have developed a new reusable device which can help women with breast cancer in lower-income countries by using carbon dioxide, a widely available and affordable gas, to power a cancer tissue-freezing probe instead of industry-standard argon.According to the study published in the journal PLOS One, the research team wanted to create a tissue-freezing tool that uses carbon dioxide, which is already widely available in most rural areas thanks to the popularity of carbonated drinks."Innovation in cancer care doesn't always mean that you have to create an entirely new treatment. Sometimes it means radically innovating on proven therapies such that they're redesigned to be accessible to the majority of the world's population," said the study's first author Bailey Surtees from the Johns Hopkins University.For the study, the research team tested their tool in three experiments to ensure it could remain cold enough in conditions similar to the human breast and successfully kill tumour tissues.In the first experiment, the team used the tool on jars of ultrasound gel, which thermodynamically mimics human breast tissue, to determine whether it could successfully reach standard freezing temperatures killing tissues and form consistent iceballs. In all the trials, the device formed large enough iceballs and reached temperatures below -40 degrees Celsius, which meets standard freezing temperatures for tissue death for similar devices in the United States.For the second experiment, the team treated 9 rats with 10 mammary tumours. Afterwards, they looked at the tissues under a microscope and confirmed that the tool successfully killed 85 per cent or more tissues for all tumours.Finally, the team tested the tool's ability to reach temperatures cold enough for tissue destruction in the normal liver of a pig, which has a temperature similar to a human breast.The device was successfully able to stay cold enough during the entire experiment to kill the target tissue.