Three-year-old Annabelle has been given just nine months to live.

Three months ago little Annabelle Potts was diagnosed with an aggressive form of brain cancer and her parents were told she might only have nine months to live.

The three-year-old has Diffuse Intrinsic Pontine Glioma (DIPG), a highly aggressive and difficult to treat tumour, found at the base of the brain.

Six months before Annabelle’s diagnosis, she began to show symptoms that made her parents, Kathie and Adam, think something wasn’t quite right. It started with sleep disturbances, dizziness, and slurred speech, before progressing to behavioural changes, vomiting and a limp.

Kathie and Adam repeatedly took Annabelle to their GP over this period, but because the tumour was hard to detect, it took months for her to be properly diagnosed.

When her parents presented Annabelle at the emergency room on Boxing Day she finally had an MRI, and they were told she had a rare form of cancer that the hospital staff had never seen before.

Annabelle was rushed to Sydney Children's Hospital, where she began an intense round of radiotherapy.

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As chemotherapy can't treat this form of cancer, and Annabelle is so young, she had to have a general anesthetic five days a week for six weeks in order to receive the radiation therapy.

"I just told her she had something growing in her head and she needed to have the magical radiation to help it shrink," explained Kathie.

In mid-February Annabelle completed the treatment. Kathie and Adam took her home to Canberra, with no guarantee of how long she would live.

"We basically had to take her home to die and just hold out hope," Kathie told Mamamia.

"It's really scary because she could wake up tomorrow and have a new symptom and that would mean the tumour has progressed."

But now Kathie and Adam have some hope. Annabelle has been accepted into a clinical trial in the UK that might extend her life and give them more time with their little girl.

The clinical trial is called Convection Enhanced Delivery (CED) and it involves the surgical implantation of very fine catheters into the brain to deliver chemotherapy directly into the tumour.

CED could extend Annabelle's life and might possibly be the life-saving treatment she so desperately needs.

Louise Griffiths, Annabelle's aunty, has started a GoFundMe campaign to help raise the $250 000 the family needs to be able to travel to the UK and take part in the clinical trial.

Since the page was set up, and thanks to the amazing support from the Canberra community, the page has already raised over $110 000. But they still need more.

Annabelle must start the trial before the end of April to have the best chance of the treatment working.

If Annabelle doesn't do the trial she will start to lose control of her senses - she won't be able to see, hear, talk, walk and lastly, she will stop breathing.

"I have to hope," said Kathie, "I need to have hope every day, otherwise I wouldn't be able to get out of bed."

You can visit Annabelle's GoFundMe page and make a donation and follow her story on Facebook.