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 15 minutes 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 (< 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.PACS numbers: 87.19.xj, 87.63.L‐, 87.59.‐e, 87.55.tg, 87.55.‐x

Assessment of the use of different imaging and delivery techniques for cranial treatments on the Halcyon linac

“…In this work we have shown the advantages of using SGRT for initial setup of cranial treatments using the Halcyon linac. However there are other sites that could also benefit from this technique such as head and neck, extremities, breast and prostate as has been shown for C‐arm linacs . We identified two limitations of the current SGRT setup.…”

“…Surface Guided Radiation Therapy (SGRT) provides an option for improved patient setup and real‐time monitoring and has been used previously for intracranial and extracranial regions . SGRT is a nonradiographic localization technique that uses a system of 3D cameras to detect a light pattern projected onto the patient and use the information to reconstruct a 3D surface image.…”

Prospective treatment plan‐specific action limits for real‐time intrafractional monitoring in surface image guided radiosurgery

“…These observations were similar to the head motion described by various authors using a number of frameless SRS imaging systems. 2,3,6,8,9,[14][15][16][17][18][19][20] Finally, the degree with which any particular transformation compromises target coverage will depend on the treatment planning strategy and conformity of the treatment. While the patients described by Peng et al were treated with up to nine noncoplanar beams, our treatments utilized multiple VMAT arcs, including coplanar and noncoplanar arcs.…”

Development of a novel remote‐controlled and self‐contained audiovisual‐aided interactive system for immobilizing claustrophobic patients

“…A number of diverse motion management techniques for brain/H&N (head and neck) immobilization have been proposed such as the simple face mask, bite block, and more aggressive head frame, (3‐5) but most of the systems are intolerable for claustrophobic patients. For example, only a few immobilization systems such as open‐face mask and head mold with a bite plate are available for the claustrophobic patient, (4,6) but they are mainly mask‐based and make the patients passive recipients of care with a certain degree of discomfort.…”