Design of the spacer for brachytherapy using ¹⁹⁸Au grain for carcinoma of the tongue as a tool of perioperative oral management

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Patients: Seventy-one and 73 years-old males visited a perioperative oral care support center to receive perioperative oral management during tongue cancer (T₁N₀M₀) treatment. To improve their quality of life (QOL) during brachytherapy while preventing radiation-related complications including osteoradionecrosis due to ¹⁹⁸Au grain brachytherapy, spacers for their maxilla and mandible were designed with consideration of wearing condition at an isolation ward. The spacer was created with unilateral design and with consideration of the tongue mobility during day and night. Then, the spacer was thickened on the plaster model, demonstrating the cancer lesion in the tongue in order to secure the distances from the mandibular body, maxilla and sublingual gland to the radiation sources embedded in the tongue.

Discussion: Tongue impression made the spacers as small as possible by thickening just around the cancer lesions so that the patients could wear them comfortably, while keeping adequate distance between the radiation sources and peripheral normal tissues. Breakable hard materials were avoided so that the patients were able to utilize the spacers safely without accidentally swallowing a broken fragment. Additionally, considering the upward movement of the tongue in a sleeping posture, the upper spacers were also prepared to protect the maxillae. Computer simulation revealed that the design of our spacers had enough effect on a reduction in radiation to prevent osteoradionecrosis in the maxilla as well as mandibular body.

Conclusions: This report demonstrated the importance of the spacers created with consideration of patients' wearing condition to improve their QOL during brachytherapy.