The invention relates to a system (1) for compressing the diaphragm and abdominal area of a patient to prevent movements that could produce a lack of precision in the area being treated during treatments such as radiotherapy. The invention comprises a support structure (2) from which protrude two rear projections (4a, 4b) intended to be applied against the renal areas of the patient and two lateral projections (5a, 5b) intended to be applied on or below the last floating ribs of the patient.
