Prospective investigation and literature review of tolerance dose on salivary glands using quantitative salivary gland scintigraphy in the intensity-modulated radiotherapy era.

BACKGROUND The purpose of this study was to prospectively evaluate the scintigraphic results on patients who undergo intensity-modulated radiotherapy (IMRT) to investigate the tolerance doses for the salivary glands. METHODS Salivary scintigraphy was performed on 35 patients with head and neck cancer before the beginning of radiotherapy (RT), and then at 6 weeks and again at 3 months after the completion of RT. Xerostomia was recorded according to the Radiation Therapy and Oncology Group (RTOG) grade. Salivary function was evaluated by calculating the excretion rate changes (ΔF) for each salivary gland before and after RT. RESULTS The parotid mean dose was significantly related to parotid ΔF and the submandibular gland mean dose to the submandibular gland ΔF. The parotid mean dose of 23 Gy was best correlated with the RTOG grades. The submandibular gland mean dose significantly related to ΔF ≤-50% and ≤-75% was 42 Gy. CONCLUSION The parotid mean dose of 23 Gy and the submandibular gland mean dose of 42 Gy is feasible for salivary function preservation in the IMRT era. © 2016 Wiley Periodicals, Inc. Head Neck 38: E1746-E1755, 2016.