Julie Higgins, 54, claimed to be an oncologist at London's Great Ormond Street Children's Hospital.
She also falsely claimed she had located transplant organs for a terminally ill woman she befriended.
The judge said he wanted to jail her but his hands were tied by the law, and he gave her a 12-month community order.
Higgins, of Spruce Close, Poole, Dorset, previously admitted pretending to be a medical practitioner and fraud by false representation.
She was also given 20 rehab activity requirement (RAR) days, 200 hours of unpaid work, a criminal Asbo and ordered to pay a Â£140 victim surcharge.
Bournemouth Crown Court heard that Higgins, who has been diagnosed with a personality disorder, had met Angela Murray, from Swanage, through a beauty salon. She had told her to go nil-by-mouth in preparation for a life-saving heart and lung transplant, claiming she had located suitable organs in Germany.
Mrs Murray, who had been told she had five years to live without the operation, was devastated when the deception was uncovered and died three weeks later in October last year.
Higgins said she had her head shaved to make her young patients feel less self-conscious. She also sent texts claiming she was on an aid mission to Syria and promised Mrs Murray her own organs if she did not make it back alive, the court was told.
Judge Donald Tait told Higgins: "You created false hope in someone who was seriously ill.
"You are a manipulative individual and you gained, for some reason, pleasure from pretending to be a medically qualified person when you weren't."
The judge said that due to the constraints of the Medical Act 1983, he was unable to jail Higgins.
"When I first read these papers I had every intention of sentencing her to prison for what she did to you but my hands are tied."
A woman who pretended to be a doctor and gave a woman with a terminal illness "false hope" has escaped a jail sentence.