The Head Mask (RG420W) is a specialized thermoplastic head immobilization device used in radiation oncology to support precise positioning and stabilization of a patient’s head and neck during radiation therapy sessions. Manufactured from medical-grade thermoplastics that soften when heated and harden into a custom contour, the RG420W mask helps clinicians deliver radiation accurately to tumors while protecting healthy tissue. These masks are standard equipment in cancer treatment centers and radiotherapy departments. Patients are fitted by trained radiation therapists, and the mask remains part of their treatment setup to ensure reproducible positioning for every session. Because this is a clinical medical device, RG420W masks are obtained through medical equipment suppliers or facility procurement for professional healthcare use. Head Mask (RG420W) Type: Radiotherapy head immobilization mask Material: Medical-grade thermoplastic Model: RG420W Perforation: 36% Thickness: 2.4 mm Primary Use: Head immobilization during radiotherapy Setting: Cancer centers, oncology departments Prescription Required: Yes — professional clinical use only