Document Type: Original Article
Research Institute for Nuclear Medicine, Tehran University of Medical Sciences, Tehran, Iran
Department of Radiation Oncology, Cancer Institute, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran
Introduction: Radioisotope scanning is the best method for objective assessment of salivary gland function. Thus, it was used in a randomized trial of concomitant pilocarpine for assessment of radiation-induced xerostomia, in addition to subjective evaluation by an approved questionnaire and objective standard xerostomia grading. Methods: Patients randomized in placebo-controlled trial of pilocarpine concurrent with irradiation for prevention of radiation-induced xerostomia were evaluated by salivary gland scintigraphy immediately before and 6 months after the end of head and neck radiotherapy. Salivary gland function was measured by ejection fraction (EF) of Technetium-99m pertechnetate. The mean values for pre and post-radiotherapy scans were calculated and compared. Also post-radiotherapy scan findings in the two groups of pilocarpine and placebo were compared using the student’s t-test. In addition, comparison was made between the scan results and the subjective findings and objective gradings. Results: Twenty patients underwent the pre-radiotherapy salivary scintigraphy, and also 20 post-radiotherapy scans were performed. Mean parotid EF was 60.85% in the pre-radiotherapy and 9.08% in the post-radiotherapy scans (P<0.01). The means for submandibular glands in the pre and post-radiotherapy scans were 41% and 11.2%, respectively (P<0.01). Also the mean EF was 14.5% in the pilocarpine group and 3.65 in the placebo group for parotid glands (P=0.07) and 18.3% and 4.1% respectively for submandibular glands (P<0.05). The salivary scans confirmed the subjective and objective xerostomia findings. Conclusion: Salivary gland scintigraphy is a valuable method for evaluation of xerostomia after head and neck radiotherapy, quantitatively demonstrating the protective effect of pilocarpine compared to placebo on salivary glands.