Height compensation system for patient table

A height compensation system for a patient table, controlling a relative position between a patient table and a gantry of a medical device, the height compensation system comprising:

• a light reflection block, which is disposed on a gantry side of the medical device or a patient table side, and is configured to reflect a received optical signal;
• a photoelectric detector, which is disposed on the gantry side or the patient table side opposite to the light reflection block, and is configured to emit an optical signal outward and detect a reflected signal of the optical signal;
• and
• a controller, which is communicably connected to the photoelectric detector, and is configured to control, when the photoelectric detector detects a reflected signal reflected by the light reflection block, the patient table to move upward in a vertical direction until the photoelectric detector does not detect the reflected signal reflected by the light reflection block.