Repositioning accuracy of a novel thermoplastic mask for head and neck cancer radiotherapy

Fukao, Mari; Okamura, Keita; Sabu, Shotaro; Akino, Yuichi; Arimura, Takehiro; Inoue, Shinichi; Kado, Ryoko; Seo, Yuji

doi:10.1016/j.ejmp.2020.05.005

Cited by 5 publications

(1 citation statement)

References 24 publications

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“…Based on the available literature and our findings, we recommend that one should try to minimise the radiation dose on the cochlea as much as possible to avoid hearing loss and keep the dose on the cochlea at least below 20 Gy if possible. Currently used radiotherapy techniques such as Volumetric-Modulated Arc Therapy (VMAT) [ 45 , 46 ], Cone-beam computed tomography [ 47 ], and improved radiotherapy masks [ 48 ] can reduce inaccuracies and prevent the unnecessary irradiation of organs at risk, for example, the cochlea.…”

Section: Discussionmentioning

confidence: 99%

Patterns of Hearing Loss in Irradiated Survivors of Head and Neck Rhabdomyosarcoma

Diepstraten

Wiersma

Schoot

et al. 2022

Cancers

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Purpose: The frequency and patterns of HL in a HNRMS survivor cohort were investigated. A dose–effect relationship between the dose to the cochlea and HL was explored. Methods: Dutch survivors treated for HNRMS between 1993 and 2017 with no relapse and at least two years after the end of treatment were eligible for inclusion. The survivors were evaluated for HL with pure-tone audiometry. HL was graded according to the Muenster, Common Terminology Criteria for Adverse Events (CTCAE) v4.03 and International Society for Paediatric Oncology (SIOP) classification. We defined deleterious HL as Muenster ≥ 2b, CTCAE ≥ 2, and SIOP ≥ 2. Mixed-effects logistic regression was used to search for the dose–effect relationship between the irradiation dose to the cochlea and the occurrence of HL. Results: Forty-two HNRMS survivors underwent pure-tone audiometry. The Muenster, CTCAE and SIOP classification showed that 19.0% (n = 8), 14.2% (n = 6) and 11.9% (n = 5) of survivors suffered from HL, respectively. A low-frequency HL pattern with normal hearing or milder hearing loss in the higher frequencies was seen in four survivors. The maximum cochlear irradiation dose was significantly associated with HL (≥Muenster 2b) (p = 0.047). In our series, HL (≥Muenster 2b) was especially observed when the maximum dose to the cochlea exceeded 19 Gy. Conclusion: HL occurred in up to 19% of survivors of HNRMS. More research is needed on HL patterns in HNRMS survivors and on radiotherapy dose–effect relationships.

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Section: Discussionmentioning

confidence: 99%

Patterns of Hearing Loss in Irradiated Survivors of Head and Neck Rhabdomyosarcoma

Diepstraten

Wiersma

Schoot

et al. 2022

Cancers

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Development of a device that remotely removes a mask in the head and neck immobilization system: a prototype and demonstration experiment

Aoyama

Shimizu

Kitagawa

et al. 2022

Radiol Phys Technol

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Development of a new poly-ε-caprolactone with low melting point for creating a thermoset mask used in radiation therapy

Aoyama

Uto

Shimizu

et al. 2021

Sci Rep

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This study aimed to develop a poly-ε-caprolactone (PCL) material that has a low melting point while maintaining the deformation ability. The new PCL (abbreviated as 4b45/2b20) was fabricated by mixing two types of PCL with different molecular weights, numbers of branches, and physical properties. To investigate the melting point, crystallization temperature, elastic modulus, and elongation at break for 4b45/2b20 and three commercially available masks, differential scanning calorimetry and tensile tests were performed. The melting point of 4b45/2b20 was 46.0 °C, and that of the commercially available masks was approximately 56.0 °C (55.7 °C–56.5 °C). The elastic modulus at 60 °C of 4b45/2b20 was significantly lower than the commercially available masks (1.1 ± 0.3 MPa and 46.3 ± 5.4 MPa, p = 0.0357). In addition, the elongation at break of 4b45/2b20 were significantly larger than the commercially available masks (275.2 ± 25.0% and 216.0 ± 15.2%, p = 0.0347). The crystallization temperature of 4b45/2b20 (22.1 °C) was clinically acceptable and no significant difference was found in the elastic modulus at 23 °C (253.7 ± 24.3 MPa and 282.0 ± 44.3 MPa, p = 0.4). As a shape memory-based thermoset material, 4b45/2b20 has a low melting point and large deformation ability. In addition, the crystallization temperature and strength are within the clinically acceptable standards. Because masks made using the new PCL material are formed with less pressure on the face than commercially available masks, it is a promising material for making a radiotherapy mask that can reduce the burden on patients.

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Repositioning accuracy of a novel thermoplastic mask for head and neck cancer radiotherapy

Cited by 5 publications

References 24 publications

Patterns of Hearing Loss in Irradiated Survivors of Head and Neck Rhabdomyosarcoma

Patterns of Hearing Loss in Irradiated Survivors of Head and Neck Rhabdomyosarcoma

Development of a device that remotely removes a mask in the head and neck immobilization system: a prototype and demonstration experiment

Development of a new poly-ε-caprolactone with low melting point for creating a thermoset mask used in radiation therapy

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