Large In-mask Motion during Frameless Radiosurgery of a Brain Metastasis

Abstract

Frameless radiosurgery is now a common alternative to traditional in-frame treatment. Several dosimetric studies have reported small in-mask positioning inaccuracies during frameless radiosurgery. We present a case of an uncommonly large deviation in in-mask motion detected offline in a patient undergoing linear accelerator–based frameless radiosurgery. Our case illustrates how the use of a thermoplastic mask can lead to unacceptable setup errors for passive image-guided radiosurgery. The case underlines the need for correct patient preparation, adequate time between mask molding and computed tomography, and routine intrafraction imaging. Image-guided positioning is recommended to achieve clinically acceptable setup accuracy (< 1 mm) for stereotactic radiosurgery.

Keywords

frameless radiosurgery - LINAC - stereotactic radiosurgery

• References

• 1 Posner JB, Chernik NL. Intracranial metastases from systemic cancer. Adv Neurol 1978; 19: 579-592
• 2 Linskey ME, Andrews DW, Asher AL. , et al. The role of stereotactic radiosurgery in the management of patients with newly diagnosed brain metastases: a systematic review and evidence-based clinical practice guideline. J Neurooncol 2010; 96 (01) 45-68
• 3 Joseph J, Adler JR, Cox RS, Hancock SL. Linear accelerator-based stereotaxic radiosurgery for brain metastases: the influence of number of lesions on survival. J Clin Oncol 1996; 14 (04) 1085-1092
• 4 Swinson BM, Friedman WA. Linear accelerator stereotactic radiosurgery for metastatic brain tumors: 17 years of experience at the University of Florida. Neurosurgery 2008; 62 (05) 1018-1031 ; discussion 1031–1032
• 5 Jezierska D, Adamska K, Liebert W. Evaluation of results of linac-based radiosurgery for brain metastases from primary lung cancer. Rep Pract Oncol Radiother 2013; 19 (01) 19-29
• 6 Das IJ, Downes MB, Corn BW, Curran WJ, Werner-Wasik M, Andrews DW. Characteristics of a dedicated linear accelerator-based stereotactic radiosurgery-radiotherapy unit. Radiother Oncol 1996; 38 (01) 61-68
• 7 Kamath R, Ryken TC, Meeks SL, Pennington EC, Ritchie J, Buatti JM. Initial clinical experience with frameless radiosurgery for patients with intracranial metastases. Int J Radiat Oncol Biol Phys 2005; 61 (05) 1467-1472
• 8 Gevaert T, Verellen D, Tournel K. , et al. Setup accuracy of the Novalis ExacTrac 6DOF system for frameless radiosurgery. Int J Radiat Oncol Biol Phys 2012; 82 (05) 1627-1635
• 9 Gevaert T, Verellen D, Engels B. , et al. Clinical evaluation of a robotic 6-degree of freedom treatment couch for frameless radiosurgery. Int J Radiat Oncol Biol Phys 2012; 83 (01) 467-474
• 10 Fu L, Perera H, Ying X, Yu Y. Importance of CBCT setup verification for optical-guided frameless radiosurgery. J Appl Clin Med Phys 2014; 15 (03) 4487
• 11 Ramakrishna N, Rosca F, Friesen S, Tezcanli E, Zygmanszki P, Hacker F. A clinical comparison of patient setup and intra-fraction motion using frame-based radiosurgery versus a frameless image-guided radiosurgery system for intracranial lesions. Radiother Oncol 2010; 95 (01) 109-115
• 12 Badakhshi H, Barelkowski T, Wust P, Budach V, Boehmer D, Graf R. Intrafraction variations in linac-based image-guided radiosurgery of intracranial lesions. Cancer Radiother 2013; 17 (07) 664-667
• 13 Bennion NR, Malouff T, Verma V. , et al. A comparison of clinical and radiologic outcomes between frame-based and frameless stereotactic radiosurgery for brain metastases. Pract Radiat Oncol 2016; 6 (06) e283-e290
• 14 Wowra B, Muacevic A, Tonn JC. Quality of radiosurgery for single brain metastases with respect to treatment technology: a matched-pair analysis. J Neurooncol 2009; 94 (01) 69-77