Leaving hospital after being diagnosed with a brain tumour, Ted Kennedy showed today that his drive and energy have not deserted him.

Smartly dressed and with his hair immaculately groomed, the Massachusetts Senator  -  the last living Kennedy brother  -  looked every inch the politician as he waved to well-wishers.

The only clue to his medical troubles was a square bandage on the back of his head.

Brave: The Senator waves to well-wishers

Enlarge 

Relief: Edward Kennedy gets a hug from his niece Caroline Kennedy. A dressing can be seen on his head

It covered the spot where doctors performed a biopsy on Monday to confirm their diagnosis of a type of brain cancer called glioma.

Experts say Kennedy is unlikely to survive for more than a year.

However, the 76-year-old Democrat seemed in good spirits as he posed for photographs in the family room of Massachusetts General Hospital on Tuesday.

With him were his sons Teddy Jr and Patrick, his daughter Kara and his stepson Curran Raclin.

Kennedy will await further test results while convalescing at home in Cape Cod.

His doctors are considering chemotherapy and radiation, but they did not mention surgery  -  a possible indication the tumour is inoperable.

Dr Keith Black, a prominent neurosurgeon, said that without surgery 'as kind of a ballpark figure you're probably looking at a survival of less than a year'.

The Senator's wife, Vicki, told friends the grim diagnosis was 'a real curveball' that left his family stunned. However, she expressed pride in how her husband was handling the news.

'Teddy is leading us all, as usual, with his calm approach to getting the best information possible,' she wrote in an email to friends.

'He's also making me crazy (and making me laugh) by pushing to race in the Figawi this weekend.' She was referring to the annual sailing race from Cape Cod to Nantucket.

Kennedy, the Senate's secondlongest serving member, is the younger brother of President John F. Kennedy, who was assassinated in 1963, and Senator Robert Kennedy, who was gunned down five years later.

The oldest Kennedy brother, Joseph, died in a plane crash in the Second World War. The tragedies thrust 'Uncle Teddy' into the role of surrogate parent to his brothers' children.

The Senator was re-elected in 2006 and is not up for election again until 2012.

If he were to resign or die in office, state law requires a special election for the seat within 145 to 160 days.

"As a general rule, at 76, without the ability to do a surgical resection, as kind of a ballpark figure you're probably looking at a survival of less than a year," said Dr. Keith Black, chairman of neurosurgery at Cedars-Sinai Medical Center in Los Angeles.

In a statement, Dr. Lee Schwamm, vice chairman of neurology at Massachusetts General, and Dr. Larry Ronan, Kennedy's primary physician, said the senator "has had no further seizures, remains in good overall condition, and is up and walking around the hospital."

Enlarge 

Dynasty: Ted, centre, with brothers Robert (left) and JFK

"He remains in good spirits and full of energy," the physicians said.

Kennedy, the Senate's second-longest serving member, was re-elected in 2006 and is not up for election again until 2012. Were he to resign or die in office, state law requires a special election for the seat 145 to 160 days afterward.

Kennedy has left his stamp on a raft of health care, pension and immigration legislation during four decades in the Senate.

In a statement, President George W. Bush saluted Kennedy as "a man of tremendous courage, remarkable strength and powerful spirit."

The Kennedy family has been frequently struck by tragedy. Kennedy's oldest brother, Joseph, died in a World War II plane crash; President John F. Kennedy was assassinated during in 1963; and Sen. Robert F. Kennedy was assassinated in 1968.

Enlarge 

Backing: Barack Obama is supported by the senator

The tragedies thrust "Uncle Teddy" into the role of surrogate parent to his brothers' children.

In 1980, Kennedy challenged Jimmy Carter for the Democratic presidential nomination. He eventually bowed out with a stirring speech in which he declared, "The cause endures, the hope still lives and the dream shall never die."

In 1969, Kennedy drove a car off a bridge on Chappaquiddick Island off Martha's Vineyard. The accident killed aide Mary Jo Kopechne.

Kennedy at the time was married to his first wife, Joan, whom he later divorced. His failure to promptly report the accident, and questions about his relationship with the young woman, may have cost him the presidency.