Investigating the displacement of radio-active sources during gold-198 grain brachytherapy for hospitalized oral cancer patients

PURPOSE: This study aimed to investigate status of displacement of gold-198 ((198)Au) grains in patients with oral cancers as well as factors and countermeasures for the displacement of (198)Au grains. MATERIAL AND METHODS: The present study included 34 patients with oral cancers, who were exclusively treated with (198)Au grain brachytherapy between 2013 and 2019. Timing and duration of the (198)Au grain displacement from the oral cavity and reduction in radiation dose were estimated. Location of the displaced grain was classified as either inside or outside of gross tumor volume. Number and location of the displacement of (198)Au grains, primary lesion, and growth type were evaluated. RESULTS: Of the 34 patients included in this study, (198)Au grains were displaced in 4 patients (11.8%) during hospitalization. A total of 5 grains (1.4%) were displaced out of an overall count of 367 grains implanted in these 34 patients. Of the four patients who experienced displacement of (198)Au grains, three had tongue cancer, and one had lip cancer. All four patients whose grains were displaced had superficial lesions. CONCLUSIONS: When performing brachytherapy with (198)Au grains for superficial lesions on the tongue or lips, care should be taken to avoid grain displacement.