PURPOSE: To compare the positioning accuracy and stability of two distinct noninvasive immobilization devices, a dedicated (D-) and conventional (C-) mask, and to evaluate the applicability of a 6-degrees-of-freedom (6D) correction, especially to the C-mask, based on our initial experience with cranial stereotactic radiotherapy (SRT) using ExacTrac (ET)/Robotics integrated into the Novalis Tx platform. MATERIALS AND METHODS: The D- and C-masks were the BrainLAB frameless mask system and a general thermoplastic mask used for conventional radiotherapy such as whole brain irradiation, respectively. A total of 148 fractions in 71 patients and 125 fractions in 20 patients were analyzed for the D- and C-masks, respectively. For the C-mask, 3D correction was applied to the initial 10 patients, and thereafter, 6D correction was adopted. The 6D residual errors (REs) in the initial setup, after correction (pre-treatment), and during post-treatment were measured and compared. RESULTS: The D-mask provided no significant benefit for initial setup. The post-treatment median 3D vector displacements (interquatile range) were 0.38 mm (0.22, 0.60) and 0.74 mm (0.49, 1.04) for the D- and C-masks, respectively (p<0.001). The post-treatment maximal translational REs were within 1 mm and 2 mm for the D- and C-masks, respectively, and notably within 1.5 mm for the C-mask with 6D correction. The pre-treatment 3D vector displacements were significantly correlated with those for post-treatment in both masks. CONCLUSIONS: The D-mask confers positional stability acceptable for SRT. For the C-mask, 6D correction is also recommended, and an additional setup margin of 0.5 mm to that for the D-mask would be sufficient. The tolerance levels for the pre-treatment REs should similarly be set as small as possible for both systems.
PURPOSE: To compare the positioning accuracy and stability of two distinct noninvasive immobilization devices, a dedicated (D-) and conventional (C-) mask, and to evaluate the applicability of a 6-degrees-of-freedom (6D) correction, especially to the C-mask, based on our initial experience with cranial stereotactic radiotherapy (SRT) using ExacTrac (ET)/Robotics integrated into the Novalis Tx platform. MATERIALS AND METHODS: The D- and C-masks were the BrainLAB frameless mask system and a general thermoplastic mask used for conventional radiotherapy such as whole brain irradiation, respectively. A total of 148 fractions in 71 patients and 125 fractions in 20 patients were analyzed for the D- and C-masks, respectively. For the C-mask, 3D correction was applied to the initial 10 patients, and thereafter, 6D correction was adopted. The 6D residual errors (REs) in the initial setup, after correction (pre-treatment), and during post-treatment were measured and compared. RESULTS: The D-mask provided no significant benefit for initial setup. The post-treatment median 3D vector displacements (interquatile range) were 0.38 mm (0.22, 0.60) and 0.74 mm (0.49, 1.04) for the D- and C-masks, respectively (p<0.001). The post-treatment maximal translational REs were within 1 mm and 2 mm for the D- and C-masks, respectively, and notably within 1.5 mm for the C-mask with 6D correction. The pre-treatment 3D vector displacements were significantly correlated with those for post-treatment in both masks. CONCLUSIONS: The D-mask confers positional stability acceptable for SRT. For the C-mask, 6D correction is also recommended, and an additional setup margin of 0.5 mm to that for the D-mask would be sufficient. The tolerance levels for the pre-treatment REs should similarly be set as small as possible for both systems.
Authors: Oliver J Gurney-Champion; Dualta McQuaid; Alex Dunlop; Kee H Wong; Liam C Welsh; Angela M Riddell; Dow-Mu Koh; Uwe Oelfke; Martin O Leach; Christopher M Nutting; Shreerang A Bhide; Kevin J Harrington; Rafal Panek; Kate L Newbold Journal: Int J Radiat Oncol Biol Phys Date: 2017-10-16 Impact factor: 7.038
Authors: Steven Babic; Young Lee; Mark Ruschin; Fiona Lochray; Alex Lightstone; Eshetu Atenafu; Nic Phan; Todd Mainprize; May Tsao; Hany Soliman; Arjun Sahgal Journal: J Appl Clin Med Phys Date: 2018-01-24 Impact factor: 2.102
Authors: Matthias Felix Haefner; Frederik Lars Giesel; Matthias Mattke; Daniel Rath; Moritz Wade; Jacob Kuypers; Alan Preuss; Hans-Ulrich Kauczor; Jens-Peter Schenk; Juergen Debus; Florian Sterzing; Roland Unterhinninghofen Journal: Oncotarget Date: 2018-01-08
Authors: Guang Li; D Michael Lovelock; James Mechalakos; Shyam Rao; Cesar Della-Biancia; Howard Amols; Nancy Lee Journal: J Appl Clin Med Phys Date: 2013-09-06 Impact factor: 2.102