"Doctor" is widely used throughout the US media without repercussion.
Dr. Phil - philosophy
Dr. Drew - medical doctor
Dr. Laura - physiology (honorary in tradition and culture from a tiny college)
Dr. Ruth - education
Dr. Oz - medical doctor
M.D. or Physician means what you think "Doctor" means. https://www.law.cornell.edu/cfr/text/20/702.404
Legally, it depends on the very lenient existing laws of the land to determine if you are prohibited (or default allowed) to be referred to as a doctor when you receive a doctorate. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5026525/ (mentioned US and CAN)