Migration from full-head mask to "open-face" mask for immobilization of patients with head and neck cancer

Guang Li, D Michael Lovelock, James Mechalakos, Shyam Rao, Cesar Della-Biancia, Howard Amols, Nancy Lee, Guang Li, D Michael Lovelock, James Mechalakos, Shyam Rao, Cesar Della-Biancia, Howard Amols, Nancy Lee

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 (< 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.

Figures

Figure 1
Figure 1
An open‐face mask and a conventional full‐head mask molded on two volunteers. An arbitrary alignment point was marked on the masks. For the open‐face mask (a), the open area was set to be the region of interest for AlignRT motion monitoring. For the conventional mask (b), the nose area was open, allowing alignment between a skin mark and the room laser in a forced motion test. A raw reference image (c), where the open area is clearly seen; the ROI (d) drawn on the reference image.
Figure 2
Figure 2
A video‐based optical surface imaging system (AlignRT) with three ceiling‐mounted stereoscopic camera pods in a treatment room with a linear accelerator (Trilogy).
Figure 3
Figure 3
Demonstration of the forced motion in four directions of a volunteer subject wearing the open‐face mask. The colored lines are movements in vertical (D.VRT), longitudinal (D.LNG), and lateral (D.LAT) directions or rotational axes. The gray line is the motion amplitude. Note that after a forced motion, the subject's position tends to fall back to within 1.5 mm of its original baseline.
Figure 4
Figure 4
Translational and rotational motion (vector) average with standard deviation (error bar) in 15 minutes for ten volunteers. The mean is 1.0 ± 0.6 mm and 0.4° ± 0.4°.
Figure 5
Figure 5
The head motion (vector) of four patients during radiation treatment in 11 to 16 fractions per patient. The mean for all patients and fractions is 1.5 mm and 0.5°, which is consistent with the volunteer data shown in Fig. 4. Although patient weight loss was observed as the mask fit more loosely in later fractions, no significant increase in motion was observed. The linear regression fit (dotted line) is shown in each graph. In the first 2 patients, the shift difference between before and after (B&A) SIC images is provided.

References

    1. Verhey LJ, Goitein M, McNulty P, Munzenrider JE, Suit HD. Precise positioning of patients for radiation therapy. Int J Radiat Oncol Biol Phys. 1982;8(2):289–94.
    1. Thornton AF, Jr. , Ten Haken RK, Gerhardsson A, Correll M. Three‐dimensional motion analysis of an improved head immobilization system for simulation, CT, MRI, and PET imaging. Radiother Oncol. 1991;20(4):224–28.
    1. Willner J, Flentje M, Bratengeier K. CT simulation in stereotactic brain radiotherapy ‐ analysis of isocenter reproducibility with mask fixation. Radiother Oncol. 1997;45(1):83–88.
    1. Gilbeau L, Octave‐Prignot M, Loncol T, Renard L, Scalliet P, Gregoire V. Comparison of setup accuracy of three different thermoplastic masks for the treatment of brain and head and neck tumors. Radiother Oncol. 2001;58(2):155–62.
    1. Tsai JS, Engler MJ, Ling MN, et al. A non‐invasive immobilization system and related quality assurance for dynamic intensity modulated radiation therapy of intracranial and head and neck disease. Int J Radiat Oncol Biol Phys. 1999;43(2):455–67.
    1. Tryggestad E, Christian M, Ford E, et al. Inter‐ and intrafraction patient positioning uncertainties for intracranial radiotherapy: a study of four frameless, thermoplastic mask‐based immobilization strategies using daily cone‐beam CT. Int J Radiat Oncol Biol Phys. 2011;80(1):281–90.
    1. Velec M, Waldron JN, O'Sullivan B, et al. Cone‐beam CT assessment of interfraction and intrafraction setup error of two head‐and‐neck cancer thermoplastic masks. Int J Radiat Oncol Biol Phys. 2010;76(3):949–55.
    1. Kang H, Lovelock DM, Yorke ED, Kriminski S, Lee N, Amols HI. Accurate positioning for head and neck cancer patients using 2D and 3D image guidance. J Appl Clin Med Phys. 2011;12(1):3270.
    1. Ohtakara K, Hayashi S, Tanaka H, et al. Clinical comparison of positional accuracy and stability between dedicated versus conventional masks for immobilization in cranial stereotactic radiotherapy using 6‐degree‐of‐freedom image guidance system‐integrated platform. Radiother Oncol. 2012;102(2):198–205.
    1. Kim S, Akpati HC, Li JG, Liu CR, Amdur RJ, Palta JR. An immobilization system for claustrophobic patients in head‐and‐neck intensity‐modulated radiation therapy. Int J Radiat Oncol Biol Phys. 2004;59(5):1531–39.
    1. Sharp L, Lewin F, Johansson H, Payne D, Gerhardsson A, Rufgvist LE. Randomized trial on two types of thermoplastic masks for patient immobilization during radiation therapy for head‐and‐neck cancer. Int J Radiat Oncol Biol Phys. 2005;61(1):250–56.
    1. Lee N, Chuang C, Quivey JM, et al. Skin toxicity due to intensity‐modulated radiotherapy for head‐and‐neck carcinoma. Int J Radiat Oncol Biol Phys. 2002;53(3):630–37.
    1. Schulte RW, Fargo RA, Meinass HJ, Slater JD, Slater JM. Analysis of head motion prior to and during proton beam therapy. Int J Radiat Oncol Biol Phys. 2000;47(4):1105–10.
    1. Ryken TC, Meeks SL, Pennington EC, et al. Initial clinical experience with frameless stereotactic radiosurgery: analysis of accuracy and feasibility. Int J Radiat Oncol Biol Phys. 2001;51(4):1152–58.
    1. Cervino LI, Pawlicki T, Lawson JD, Jiang SB. Frame‐less and mask‐less cranial stereotactic radiosurgery: a feasibility study. Phys Med Biol. 2010;55(7):1863–73.
    1. Li G, Ballangrud A, Kuo LC, et al. Motion monitoring for cranial frameless stereotactic radiosurgery using video‐based three‐dimensional optical surface imaging. Med Phys. 2011;38(7):3981–94.
    1. Peng JL, Kahler D, Li JG, et al. Characterization of a real‐time surface image‐guided stereotactic positioning system. Med Phys. 2010;37(10):5421–33.
    1. Li S, Liu D, Yin G, Zhuang P, Geng J. Real‐time 3D‐surface‐guided head refixation useful for fractionated stereotactic radiotherapy. Med Phys. 2006;33(2):492–503.
    1. Linthout N, Verellen D, Tournel K, Storme G. Six dimensional analysis with daily stereoscopic x‐ray imaging of intrafraction patient motion in head and neck treatments using five points fixation masks. Med Phys. 2006;33(2):504–13.

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