A doctor was sentenced on Tuesday to 18 years in prison for the consensual killing of a woman with amyotrophic lateral sclerosis, a rare neurological disease also known as Lou Gehrig's disease, in 2019 in Kyoto, western Japan.

The Kyoto District Court found 45-year-old Yoshikazu Okubo guilty of administering a lethal dose of a sedative to Yuri Hayashi in her apartment on Nov. 30, 2019, at her request. Prosecutors had sought a prison term of 23 years.

ALS is a progressive neurological condition for which there is currently no cure or known treatment.

Presiding Judge Hiroshi Kawakami said that Okubo was not Hayashi's attending physician and killed her after meeting her for the first time.

According to the ruling, Okubo and former doctor Naoki Yamamoto, 46, administered a fatal dose of drugs to Hayashi, who was later rushed to a hospital before dying.

Yamamoto was sentenced to two years and six months in prison last December for conspiring with Okubo for the consensual killing of Hayashi.

Prosecutors had argued that the case "did not fulfill the minimum requirement for euthanasia."

Meanwhile, Okubo's defense team argued that without euthanasia, Hayashi "would have been forced to live a life under the constant fear of death." His act fulfilled her wish, and ruling Okubo guilty of murder would violate the Constitution's right to self-determination, they said.

In Japan, euthanasia is not legally recognized. Under the Penal Code, a person who kills someone at the request of that person or with their consent can face a prison term of between six months and seven years.

Okubo was also found guilty of killing Yamamoto's 77-year-old father, Yasushi, in 2011, in conspiracy with Yamamoto.