Effect of immobilization materials on surface dose

The accuracy of the radiotherapy treatment depends mainly on immobilization of patients during treatment. Commercially available immobilisation materials like plaster of paris, acrylic and thermoplastics are being used for immobilisation at our centre. Patients treated with above said materials developed increased skin reactions. Our objective is to determine the effect of incidence dose on the skin and skin sparing effect of megavoltage beam, while using the above materials as immobilization