CLARKSTON, MICH., DEC. 13 -- A state judge dismissed a first-degree murder charge today against Dr. Jack Kevorkian, inventor of a suicide device, saying he broke no law in helping a patient with Alzheimer's disease kill herself.

District Judge Gerald McNally announced his decision after hearing a tape of Janet Adkins discussing her fight against the disease, which causes irreversible brain degeneration. "I've had enough," she said on the tape.

Adkins suffered from Alzheimer's disease but might still be alive had she not turned on Kevorkian's device June 4, McNally said at the end of Kevorkian's two-day preliminary examination.

But because Michigan law does not outlaw suicide or assisting in it, prosecutors had no case against Kevorkian, McNally said in dismissing the charge against Kevorkian, 62, a retired pathologist from Royal Oak, Mich.

There was scattered applause in the courtroom as Kevorkian turned without expression to shake the hand of his lawyer, Geoffrey Fieger. "I feel like I'm walking on a cloud," Kevorkian said on his way out of the courthouse.

Michael Modelski, chief assistant Oakland County prosecutor, said his office was considering whether to appeal to Circuit Court. That court could reinstate the first-degree murder charge or a lesser charge, such as second-degree murder or manslaughter, he said.

Despite the dismissal, Kevorkian is not free to use his device again. Three days after Adkins died, prosecutors obtained a temporary court order preventing its further use. The contraption remains in police custody pending a civil trial, probably in January, on whether that order should be made permanent, Fieger said.

Autopsy results released in late November showed that Adkins, 54, of Portland, Ore., committed suicide with an overdose of medication. Fieger said in closing arguments that Kevorkian attached an intravenous tube to her right arm but that it carried only a harmless saline solution.

The drugs that caused Adkins to lose consciousness and then stopped her heart did not enter her body until after she threw the switch on Kevorkian's device, Fieger said.