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Sakamoto M, Konishi K, Ohira K, Hirata M, Wakabayashi K, Aramaki S, Kokubo R, Nakamura K. A newly developed patient fixation system using a dedicated mouthpiece and dental impression materials for head and neck radiotherapy: a preliminary study. J Radiat Res 2022; 63:749-757. [PMID: 35818301 PMCID: PMC9494543 DOI: 10.1093/jrr/rrac044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/21/2022] [Indexed: 06/15/2023]
Abstract
We evaluated the basic characteristics and efficacy of our newly developed patient fixation system for head and neck radiotherapy that uses a dedicated mouthpiece and dental impression materials. The present investigation demonstrated that with this system, the changes in the absorbed dose to water depending on the material of the mouthpiece were small, with a maximum of 0.32% for a 10-MV photon beam. For the dental impression material, we selected a silicone material with the lowest Hounsfield unit (HU) value that had little effect on the generation of artifacts and the quality of the X-ray beam. Multiphase magnetic resonance imaging (MRI) revealed that the head-up and -down motions in the thermoplastic shell without the mouthpiece were 5.76 ± 1.54 mm, whereas the motion with the mouthpiece decreased significantly to 1.72 ± 0.92 mm (P = 0.006). Similarly, the head-left and -right motion displacement decreased from 6.32 ± 1.86 mm without the mouthpiece to 1.80 ± 0.42 mm with the mouthpiece (P = 0.003). Regarding the tongue depressor function of the mouthpiece, the median distance from the hard palate to the surface of the tongue was 28.42 mm. The present results indicate that the new immobilization device developed herein that uses a mouthpiece and a thermoplastic shell is useful for suppressing patients' head motions and tongue positions.
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Affiliation(s)
- Masataka Sakamoto
- Corresponding author. Department of Radiology, Hamamatsu University Hospital, Handayama 120-1, Higashi-ku, Hamamatsu 431-3192, JAPAN. Tel: +81-053-435-2111; E-mail:
| | - Kenta Konishi
- Department of Radiation Oncology, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Keiichi Ohira
- Department of Radiation Oncology, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Masanori Hirata
- Department of Radiation Oncology, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Kohei Wakabayashi
- Department of Radiation Oncology, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Shuhei Aramaki
- Department of Radiation Oncology, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Ryo Kokubo
- Department of Radiation Oncology, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
| | - Katsumasa Nakamura
- Department of Radiology, Hamamatsu University Hospital, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
- Department of Radiation Oncology, Hamamatsu University School of Medicine, Handayama 1-20-1, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan
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