title: Migration from full-head mask to "open-face" mask for immobilization of patients with head and neck cancer.
abstract: To provide an alternative device for immobilization of the head while easing claustrophobia and improving comfort, an "open-face" thermoplastic mask was evaluated using video-based optical surface imaging (OSI) and kilovoltage (kV) X-ray radiography. A three-point thermoplastic head mask with a precut opening and reinforced strips was developed. After molding, it provided sufficient visible facial area as the region of interest for OSI. Using real-time OSI, the head motion of ten volunteers in the new mask was evaluated during mask locking and 15minutes lying on the treatment couch. Using a nose mark with reference to room lasers, forced head movement in open-face and full-head masks (with a nose hole) was compared. Five patients with claustrophobia were immobilized with open-face masks, set up using OSI and kV, and treated in 121 fractions, in which 61 fractions were monitored during treatment using real-time OSI. With the open-face mask, head motion was found to be 1.0 ± 0.6 mm and 0.4° ± 0.2° in volunteers during the experiment, and 0.8 ± 0.3 mm and 0.4° ± 0.2° in patients during treatment. These agree with patient motion calculated from pre-/post-treatment OSI and kV data using different anatomical landmarks. In volunteers, the head shift induced by mask-locking was 2.3 ± 1.7 mm and 1.8° ± 0.6°, and the range of forced movements in the open-face and full-head masks were found to be similar. Most (80%) of the volunteers preferred the open-face mask to the full-head mask, while claustrophobic patients could only tolerate the open-face mask. The open-face mask is characterized for its immobilization capability and can immobilize patients sufficiently (&lt; 2 mm) during radiotherapy. It provides a clinical solution to the immobilization of patients with head and neck (HN) cancer undergoing radiotherapy, and is particularly beneficial for claustrophobic patients. This new open-face mask is readily adopted in radiotherapy clinic as a superior alternative to the standard full-head mask.
authors.affiliation: Memorial Sloan-Kettering Cancer Center. lig2@mskcc.org.
authors.forename: Guang
authors.initials: G
authors.lastname: Li
authors.forename: D Michael
authors.initials: DM
authors.lastname: Lovelock
authors.forename: James
authors.initials: J
authors.lastname: Mechalakos
authors.forename: Shyam
authors.initials: S
authors.lastname: Rao
authors.forename: Cesar
authors.initials: C
authors.lastname: Della-Biancia
authors.forename: Howard
authors.initials: H
authors.lastname: Amols
authors.forename: Nancy
authors.initials: N
authors.lastname: Lee
mesh_terms: D000368:Aged; D004867:Equipment Design; D005260:Female; D006257:Head / Q000000981:diagnostic imaging*; D006258:Head and Neck Neoplasms / Q000000981:diagnostic imaging / Q000523:psychology / Q000532:radiotherapy*; D006801:Humans; D007103:Immobilization; D008297:Male; D008397:Masks / Q000592:standards*; D008875:Middle Aged; D009038:Motion; D010698:Phobic Disorders / Q000523:psychology*; D011859:Radiography; D020266:Radiotherapy, Conformal / Q000295:instrumentation / Q000379:methods* / Q000523:psychology
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