A radiographer at a private Bristol hospital was found drinking neat gin from a Lucozade bottle, a disciplinary panel heard.
The Health and Care Professions Council said Anne M Clews was seen by her line manager drinking in a locker area after disappearing from her post at the Spire Bristol Hospital on Redland Hill, next to Durdham Down.
She has been suspended for a year by the independent healthcare regulator at a hearing in Cardiff.
An HCPC Conduct and Competence Committee panel heard Mrs Clews was working in the hospital's MRI department, where diagnostic scans are carried out.
Mrs Clews did not attend and was not represented at the hearing in London last week.
The panel found that by a fortnight into Mrs Clews' employment at the Spire Bristol Hospital in January last year her line manager, Simon Holmes, had noticed her performance was not improving and she "made persistent errors in tasks where only very basic MRI skills were required".
Despite constant supervision, the panel heard, Mr Holmes "felt unable to leave her unsupervised, because otherwise her work fell short of the required standards and she lacked the ability to concentrate".
On April 30, Mr Holmes had noticed Mrs Clews was unable to perform a "basic task" on three occasions. He described her as "especially vacant" throughout that day.
In its finding, the HCPC panel said: "At 6pm the Registrant went missing. Simon Holmes found her in a locker area, kneeling down drinking from a Lucozade bottle. Mr Holmes was suspicious because she usually kept her drinks in the MRI control room.
"The liquid she was drinking was clear rather than orange and she placed the bottle back into her bag when she saw him. He examined the bottle ... (she) had been drinking from later and found it appeared to contain neat gin."
It was reported to the human resources department.
Three days later, the panel heard, Mr Holmes again found a soft drink bottle which appeared to be full of neat gin in Mrs Clews' bag. He accused her of drinking on duty. She denied drinking that day but admitted drinking on the previous occasion. She was formally suspended and escorted off the premises.
The HCPC said Mrs Clews "realises the matters are serious and that she has been highly unprofessional".
Finding Mrs Clews' guilty of misconduct and her fitness to practise impaired, she was formally suspended for a year, although the panel was told she had already resigned from her post last May.