Integrazione della riduzione della mobilità respiratoria nel trattamento radiante esterno conformazionale

Several methods to reduce respiratory-induced motion have been described in literature, with the goal of increasing accuracy of treatment to minimize normal tissue toxicity or increase dose to the target volume. We analyzed two different techniques of respiratory gating: the deep inspiration breath hold technique and the respiratory gating using the Real-time Position Management (RPM) system. The first method is a self-gating technique in which radiation treatment take place during a phase of breath-holding. The second technique use a reflective marker placed on the patient’s anterior surface. The motion of the marker is tracked using a camera interfaced to a computer. The gating thresholds are set when the tumor is in the desired portion of the respiratory cycle. These thresholds determine when the gating system turns the treatment beam on and off. We compared both techniques with a standard external radiation treatment. The dosimetric analysis has led to considerable advantage of these methods compared to the external radiation treatment, particularly in reducing the dose to the lung.