Juan, a self-employed medical doctor, has an office in his home where he maintains patient records and performs billing procedures. Most of his time is spent visiting patients and performing surgical procedures in the operating room at several local hospitals. Juan intends to deduct his expenses for the office in his home. What tax issues should Juan consider? Please discuss the applicable tax authority, including any relevant Supreme Court cases and changes to the Internal Revenue Code that might have come about as a result of the Supreme Court's decision.

Please elaborate as much as you can.