Dr. Peter Goodwin died at 82 after taking lethal medication legal in Oregon.

One of the first physicians to voice support for Oregon's controversial assisted-suicide legislation in the early 1990s has used the state's Death with Dignity Act to end his own life.

Dr. Peter Goodwin died March 11 after taking lethal medication. He was 82 and suffered from a fatal brain disease.

Goodwin was surrounded by his four children and their spouses, according to the advocacy group Compassion & Choices, which announced his death. The medication - a fast-acting barbituate - gave Goodwin a "peaceful death" in less than 30 minutes, they said.

"It was a good death and the family appreciated that," organization spokesman Steve Hopcraft told ABCNews.com. "Peter was unique."

Hopcraft said the family was "grieving" and not yet giving interviews.

In 2006, Goodwin had been diagnosed with a rare and fatal brain disease known as corticobasal degeneration, which can affect balance, muscle control and speech, as well as cognition. By January, his doctors estimated he had six months to live.

Last year, he had talked about how he wanted to find the right time to end his own life, according to the Oregonian newspaper.

"I don't want to die," he said then. "No way do I want to die. I enjoy life; I enjoy company; I enjoy my friends. I have many, many, many friends."

Under the Oregon law, doctors can prescribe medication to hasten the death of a terminally ill patient with a six-month prognosis. The patients must be mentally competent and administer the medication themselves.

More than 500 people have used the Oregon law to end their lives. The initiative - the first in the country - has survived a Supreme Court challenge. Physician-assisted death is also legal in Washington state.

Born in London and raised in South Africa, Goodwin practiced as a family physician in Oregon and Washington for five decades.  In the fight to pass Oregon's Death With Dignity Act in the early 1990s, he was widely credited for neutralizing the Oregon Medical Association, which could have seen the measure fail at the ballot.

Goodwin has said he first became interested in the cause 20 years ago when a  patient asked for his help. The patient had a fatal spinal tumor and was in severe pain.

The patient's wife asked Goodwin if she could administer a prescription, but he ultimately refused, telling her it was against the law.

He retold the story to the Oregon legislature, saying his inability to act when the man was in such pain made Goodwin feel like a coward, according to the Oregonian.

"We cannot deal compassionately with people if we limit their options," he reportedly said.

Goodwin later served as was the first medical director of Compassion & Choices, which continues to fight for "death with dignity" efforts in states like Massachusetts and Hawaii.

"I was  honored to call Peter Goodwin a compatriot and a friend," said its president Barbara  Coombs Lee. "Our hearts are broken at this loss. The state of Oregon, medicine and the world have lost a great leader. Most of all, our sympathies are with  his family, whom he dearly loved."