Robert Franklin, Associated Press
In this Sept. 5, 2014 photo, wild marijuana plants are displayed in an area southwest of South Bend, Ind. A judge will consider Tuesday whether to send a dying Iowa man to prison for a drug conviction that he says stemmed from his use of marijuana to treat terminal cancer.

DAVENPORT, Iowa — A judge will consider Tuesday whether to send a dying Iowa man to prison for a drug conviction that he says stemmed from his use of marijuana to treat terminal cancer.

Benton Mackenzie, 48, has said he faces a minimum sentence of three years in prison. Mackenzie suffers from a rare cancer of the blood vessels, and he says any prison term would amount to a death sentence.

Judge Henry Latham has the authority to suspend any prison sentence.

Latham is also expected to sentence Mackenzie's wife, 43-year-old Loretta Mackenzie, and their 23-year-old son, Cody Mackenzie, on Tuesday afternoon at the Scott County Courthouse in Davenport.

All three were charged following a June 2013 raid at the Long Grove, Iowa, home where they live with Mackenzie's parents, Dorothy and Charles Mackenzie. Sheriff's deputies found 71 marijuana plants, growing equipment, drug paraphernalia and a small amount of marijuana in Cody's room.

Mackenzie, who uses a wheelchair, said he grew the plants to obtain cannabis oil that he used to treat his angiosarcoma, which causes skin lesions. He said the oil relieved his pain and helped to reduce the size of one lesion.

At trial, Latham repeatedly barred Mackenzie from testifying about his cancer, noting that a medical necessity defense is not allowed in Iowa.

Jurors in July found Mackenzie and his wife guilty of manufacturing marijuana and related charges. Their son was found guilty of misdemeanor possession of marijuana.

Iowa has passed a law that will allow the most severe epilepsy patients to use cannabis oil for treatment. But the law doesn't apply to cancer patients and therefore didn't help Mackenzie. After the trial he traveled to buy marijuana in Oregon — one of 20 states that permits medical marijuana.

Mackenzie's supporters have organized online, and some are expected to attend Tuesday's sentencing.

More than 16,600 people have signed a petition urging the Scott County Attorney's Office to drop the case. Others are urging Gov. Terry Branstad to issue a pardon. A Branstad spokesman said it would be premature to comment since the case is still pending.

Scott County Attorney Mike Walton has defended the prosecution, saying he is enforcing the state's marijuana laws as written. He has noted that Benton Mackenzie has two prior felony drug convictions from 2000 and 2011, which makes him a "habitual offender" and subject to the three-year mandatory minimum sentence.

Walton's office recently dropped charges of hosting a drug house against Dorothy and Charles Mackenzie, who are in their 70s, stemming from the same raid.