His family released a statement Tuesday night that said their hearts go out to the doctor's family and friends.
"We are praying for them and his recovery. No words can truly express how heartbroken we are by this tragedy. We are saddened and struggling to makse sense of what transpired and ask that you respect our privacy during this time."
Pasceri, who had a license to carry a firearm, was later found dead from a "self-inflicted gunshot wound," police said.
"We have a doctor from Brigham and Women's who sustained what we believe to be two gunshot wounds. He is in life-threatening condition," Boston Police Commissioner William Evans said.
Marguerite Pasceri, who died Nov. 15, was a patient of the doctor, sources told NewsCenter 5.
"We are looking at a possible motive. We know (the gunman) came into the hospital on the second floor looking for this particular doctor. There was a reason he targeted this doctor," Evans said.
Evans said the doctor's colleagues were able to get him medical help immediately. Police did not identify the victim, but said their prayers go out to his wife.
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"This evening the physician, who will remain anonymous at the request of his family, is in surgery," said hospital spokeswoman Erin McDonough.
Witnesses described the scene inside the Shaprio building, which was briefly placed on lockdown following the shooting.
"Once we were clear of the waiting room, there were police officers with their weapons drawn, yelling, 'Get down! Get down!'" said James Pittelli, whose son is undergoing a procedure at the hospital.
Roads in the area were closed for about an hour.
In 2003, a woman shot and killed prominent cardiologist Dr. Brian McGovern inside Massachusetts General Hospital before turning the gun on herself.