open access
Utility of intraoral stents in external beam radiotherapy for head and neck cancer
open access
Abstract
Aim
This study aimed to assess the utility and stability of intraoral stent during intensity-modulated radiation therapy (IMRT).
Background
The benefits of intraoral stents in radiotherapy are unclear.
Materials and methods
We analyzed 386 setup errors in 12 patients who received IMRT for head and neck cancers without intraoral stents (intraoral stent [−]) and 183 setup errors in 6 patients who received IMRT with intraoral stents (intraoral stent [+]). All patients were matched according to the immobilization method (masks and boards). Setup errors were measured as the distance from the initial setup based on the marking on the skin and mask to the corrected position based on bone matching on cone beam computed tomography.
Results
The mean interfractional setup errors in the right–left, craniocaudal, anterior–posterior (AP), and three-dimensional (3D) directions were −0.33, 0.08, −0.25, and 2.75[[ce:hsp sp="0.25"/]]mm in the intraoral stent (−) group and −0.37, 0.24, −0.63, and 2.42[[ce:hsp sp="0.25"/]]mm in the intraoral stent (+) group, respectively (P[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.50, 0.65, 0.01, and 0.02, respectively). The systematic errors for the same directions were 0.89, 1.46, 1.15, and 0.88[[ce:hsp sp="0.25"/]]mm in the intraoral stent (−) group and 0.62, 1.69, 0.68, and 0.56[[ce:hsp sp="0.25"/]]mm in the intraoral stents (+) group, respectively. The random errors were 1.43, 1.43, 1.44, and 1.22[[ce:hsp sp="0.25"/]]mm in the intraoral stent (−) group and 1.06, 1.11, 1.05, and 0.92[[ce:hsp sp="0.25"/]]mm in the intraoral stents (+) group, respectively.
Conclusion
Setup errors can be significantly reduced in the AP and 3D-directions by using intraoral stents.
Abstract
Aim
This study aimed to assess the utility and stability of intraoral stent during intensity-modulated radiation therapy (IMRT).
Background
The benefits of intraoral stents in radiotherapy are unclear.
Materials and methods
We analyzed 386 setup errors in 12 patients who received IMRT for head and neck cancers without intraoral stents (intraoral stent [−]) and 183 setup errors in 6 patients who received IMRT with intraoral stents (intraoral stent [+]). All patients were matched according to the immobilization method (masks and boards). Setup errors were measured as the distance from the initial setup based on the marking on the skin and mask to the corrected position based on bone matching on cone beam computed tomography.
Results
The mean interfractional setup errors in the right–left, craniocaudal, anterior–posterior (AP), and three-dimensional (3D) directions were −0.33, 0.08, −0.25, and 2.75[[ce:hsp sp="0.25"/]]mm in the intraoral stent (−) group and −0.37, 0.24, −0.63, and 2.42[[ce:hsp sp="0.25"/]]mm in the intraoral stent (+) group, respectively (P[[ce:hsp sp="0.25"/]]=[[ce:hsp sp="0.25"/]]0.50, 0.65, 0.01, and 0.02, respectively). The systematic errors for the same directions were 0.89, 1.46, 1.15, and 0.88[[ce:hsp sp="0.25"/]]mm in the intraoral stent (−) group and 0.62, 1.69, 0.68, and 0.56[[ce:hsp sp="0.25"/]]mm in the intraoral stents (+) group, respectively. The random errors were 1.43, 1.43, 1.44, and 1.22[[ce:hsp sp="0.25"/]]mm in the intraoral stent (−) group and 1.06, 1.11, 1.05, and 0.92[[ce:hsp sp="0.25"/]]mm in the intraoral stents (+) group, respectively.
Conclusion
Setup errors can be significantly reduced in the AP and 3D-directions by using intraoral stents.
Keywords
Intensity modulated radiation therapy; Setup error; Head and neck cancer; Bite block immobilization; Radiotherapy
About this articleTitle
Utility of intraoral stents in external beam radiotherapy for head and neck cancer
Journal
Reports of Practical Oncology and Radiotherapy
Issue
Pages
310-318
Published online
2017-07-01
DOI
10.1016/j.rpor.2017.03.002
Bibliographic record
Rep Pract Oncol Radiother 2017;22(4):310-318.
Keywords
Intensity modulated radiation therapy
Setup error
Head and neck cancer
Bite block immobilization
Radiotherapy
Authors
Hiroshi Doi
Masao Tanooka
Toshihisa Ishida
Kuniyasu Moridera
Kenji Ichimiya
Kazuo Tarutani
Kazuhiro Kitajima
Masayuki Fujiwara
Hiromitsu Kishimoto
Norihiko Kamikonya