Skin-sparing benefits derived from the use of megavoltage photon beams can be strongly reduced when filters are inserted between the source and the patient. The use of plastic masks for immobilizing the patient is the most important cause of this reduction in head and neck treatments. The influence of thermoplastics, commercially available for patient immobilization systems (Orfit Raycast (Luxilon Ind. Co.), Posicast (Sinmed bv) and Optimold (WFR Aquaplast Corp.)), on the patient skin dose value has been investigated by using an NE2534 'Markus' chamber. Indicative measurements with moulded masks (carried out with 2-mm Orfit and3.2-mm Optimold layers) show significant differences between masks moulded with the two thermoplastics.
- Head and neck tumors
- Plastic immobilization masks
- Skin dose
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging