Development of a semi-customized tongue displacement device using a 3D printer for head and neck IMRT

Chae-Seon Hong,Dongryul Oh,Dong Yeol Kwon,Cheol Chong Kim,Cho Hee Na,Sang Gyu Ju,Yong Chan Ahn

doi:10.1186/s13014-019-1289-x

Abstract

PurposeTo reduce radiation doses to the tongue, a patient-specific semi-customized tongue displacement device (SCTDD) was developed using a 3D printer (3DP) for head and neck (H&N) radiation therapy (RT). Dosimetric characteristics of the SCTDD were compared with those of a standard mouthpiece (SMP).Materials and methodsThe SCTDD consists of three parts: a mouthpiece, connector with an immobilization mask, and tongue displacer, which can displace the tongue to the contralateral side of the planning target volume. Semi-customization was enabled by changing the thickness and length of the SCTDD. The instrument was printed using a 3DP with a biocompatible material. With the SCTDD and SMP, two sets of planning computed tomography (CT) and tomotherapy plans were obtained for seven H&N cancer patients. Dosimetric and geometric characteristics were compared.ResultsUsing the SCTDD, the tongue was effectively displaced from the planning target volume without significant tongue volume change compared to the SMP. The median tongue dose was significantly reduced (29.6 Gy vs. 34.3 Gy). The volumes of the tongue receiving a dose of 15 Gy, 30 Gy, 35 Gy, 45 Gy, and 60 Gy were significantly lower than using the SMP.ConclusionThe SCTDD significantly decreased the radiation dose to the tongue compared to the SMP, which may potentially reduce RT-related tongue toxicity.

Highlights

Radiation therapy (RT) has played an important role as a standard treatment for head and neck squamous cell carcinoma (HNSCC) [1,2,3,4] with surgery and chemotherapy
Using the semi-customized tongue displacement device (SCTDD), the tongue was effectively displaced from the planning target volume without significant tongue volume change compared to the standard mouthpiece (SMP)
It is not an easy task to meet the aim of RT, which delivers a curable dose to a target volume while minimizing the dose to organs at risk (OARs) near the target volume because head and neck (H&N) tumors usually overlap or are adjacent to normal organs

Summary

Introduction

Radiation therapy (RT) has played an important role as a standard treatment for head and neck squamous cell carcinoma (HNSCC) [1,2,3,4] with surgery and chemotherapy. There are many OARs of concern in the RT planning for H&N cancer, such as the brain, brainstem, optic apparatus, The tongue is a subsite of the OC and is not separately described in the OAR delineation guidelines [8]. It plays important roles in taste, saliva production, speech, and swallowing [5, 7, 9, 10], so it is important to minimize the radiation dose to the tongue for better quality of life following RT. Shi. et al reported that significant impaired threshold of taste was revealed at 30 Gy [12]

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Results

Conclusion