Open AccessIntra‐fractional motion error during HyperArc stereotactic radiosurgery on patients with brain metastases: Comparison of open and full‐face clamshell‐style immobilization devices
Author(s) -
Ohira Shingo,
Komiyama Riho,
Kanayama Naoyuki,
Ueda Yoshihiro,
Inui Shoki,
Miyazaki Masayoshi,
Koizumi Masahiko,
Konishi Koji
Publication year - 2022
Publication title -
journal of applied clinical medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.83
H-Index - 48
ISSN - 1526-9914
DOI - 10.1002/acm2.13536
Subject(s) - radiosurgery , face (sociological concept) , motion (physics) , stereotactic radiotherapy , medical physics , nuclear medicine , medicine , computer science , radiology , artificial intelligence , radiation therapy , social science , sociology
Purpose To compare the intrafractional motion error (IME) during stereotactic irradiation (STI) in patients with brain metastases immobilized using open‐ (Encompass) and full‐face (DSPS) clamshell‐style immobilization devices. Methods Encompass (38 patients) and DSPS (38 patients) were used for patient immobilization, and HyperArc plans with three to four non‐coplanar beams were generated to deliver 25 to 35 Gy in three to five fractions. Cone‐beam computed tomography (CBCT) was performed on patients before and after the treatment. Moreover, the difference in patient position between the two CBCT images was considered as the IME. The margins to compensate for IME were calculated using the van Herk margin formula. Results For Encompass, the mean values of IME in the translational setup were 0.1, 0.2, and 0.0 mm in the anterior–posterior, superior–inferior, and left–right directions, respectively, and the mean values of IME about rotational axes were −0.1, 0.0, and 0.0° for the Pitch, Roll, and Yaw rotations, respectively. For DSPS, the mean values of IME in the translational setup were 0.2, 0.2, and 0.0 mm in the anterior–posterior, superior–inferior, and left–right directions, respectively, and the mean values of IME about rotational axes were −0.1, −0.1, and 0.0° for the Pitch, Roll, and Yaw rotations, respectively. No statistically significant difference was observed between the IME of the two immobilization systems except in the anterior–posterior direction ( p = 0.02). Moreover, no statistically significant correlation was observed between three‐dimensional IME and treatment time. The margin compensation for IME was less than 1 mm for both immobilization devices. Conclusions The IME during STI using open‐ and full‐face clamshell‐style immobilization devices is approximately equal considering the adequate accuracy in patient positioning.