ELAINE DAVIDSON was 15 when doctors said she must be pregnant. She was suffering severe bouts of sickness and a constant headache and doctors made her take repeated pregnancy tests.

But her mum Maureen refused to believe them and, after almost four months, doctors finally sent Elaine to Glasgow Royal Infirmary for further tests. There, they discovered what was wrong - she had a brain tumour the size of a golf ball.

Elaine, who is now 17, became ill in June 2006, just after finishing her Standard grades at Bannerman High School.

She was constantly being sick and had a sensitivity to light. Her mum says she took her to Baillieston Health Centre almost a dozen times, but was told her daughter had a migraine and was sent away.

When Elaine made further visits to an out-of-hours clinic at Easterhouse Health Centre she was told she must be pregnant.

Maureen, 43, of Baillieston, said: "Elaine must have had five or six pregnancy tests.

"Every time we went the doctors said she was pregnant. Sometimes she was so ill she couldn't even take the test. They even gave her a sick bowl, which she filled. It was all black and they still did not refer her."

Elaine said: "I told them I had been lying on the couch all summer and had not even been out of the door because I was too ill, so how could I be pregnant?"

Her health had got so bad she could not leave the house, she had to be lifted in and out of the bath, and could, not dress herself Maureen said: "We wanted it to be migraines, but we knew she was really ill. One day, I promised Elaine we would not leave the doctor's surgery until we got an answer."

Staff at the Royal Infirmary gave Elaine a scan and, on September 11, 2006, they diagnosed a tumour.

She was rushed to the Southern General and, two days later, surgeons removed the tumour.

Her mum, dad George, 44, who is a delivery driver, and sister Nicola, 20, were shocked to find it was cancerous.

Maureen said: "It was devastating. But I knew how ill she was."

Elaine missed her fifth year at school as she battled the disease. She had chemotherapy for a year in the Schiehallion Ward at Yorkhill Hospital For Sick Children and radiotherapy at the Beatson West of Scotland Cancer Centre.

However, there was some relief from her gruelling treatment. Fundraiser Les Hoey arranged for Elaine to meet pop band Westlife and X Factor judges Simon Cowell and Dannii Minogue.

Last month, Elaine was given the all-clear and now she is fighting a new battle - to help raise money for the Teenage Cancer Trust to build a new hospital unit at Yorkhill especially for young patients.

Although she often has to use a wheelchair because the chemotherapy affected her feet muscles, Elaine has been out in the city's East End trying to persuade firms to take collecting tins to help gather cash. It is part of her role of the charity's West of Scotland committee.

She is also holding a race night in aid of the unit and her dad and his pals from the Centaur Bar, Easterhouse, will run the freshnlo half marathon in September to raise funds.

Elaine was given the choice of being treated at the children's hospital at Yorkhill or with adults.

And she said if there had been a teenage unit while she was ill, like the one at the Beatson, it would have made things a lot more pleasant.

"When I was in Yorkhill I did not like it that there was nothing for people my age, so I want to improve it. There will be the internet and a television and it will be away from the babies and children crying," she said.

Elaine is also getting her life back on track. She is going to Cardonald College next month to take Highers in English, maths, modern studies and administration and hopes to become a teacher.

Simon Davies, Teenage Cancer Trust chief executive, said, "Elaine is an inspiring young lady. Her involvement will help us ensure other young people like Elaine, will have access to a specialised treatment centre in the region."

An NHS Greater Glasgow and Clyde spokeswoman said: "This patient was seen by our out-of-hours service in September 2006.

"We have had no communication from the family around their daughter's care. However, we would be happy to discuss with the patient or her family the treatment and advice given."