Predictive value of posttreatment whole body scan for radiation damage to the salivary glands in patients with differentiated thyroid carcinoma

Objective: To evaluate the predictive value of posttreatment whole body scan (Rx-WBS) for radiation damage to the salivary glands in patients with differentiated thyroid carcinoma (DTC). Methods: From April 2015 to June 2015, 24 patients (8 males, 16 females; age: 26-64 years) with DTC, who accepted ¹³¹I therapy only one time and underwent Rx-WBS 2-4 d after ¹³¹I treatment, were recruited from the First Hospital of China Medical University. All patients had normal salivary glands function on salivary gland scintigraphy (SGS) performed on the day before ¹³¹I treatment, and 21 patients underwent SGS again 3 months after ¹³¹I treatment. The SGS results and clinical manifestations were used to evaluate the function of salivary glands after ¹³¹I therapy. Rx-WBS was analyzed by visual analysis and quantitative analysis (salivary gland to background uptake ratios, SUR). The SUR was compared between patient groups with different function of salivary glands. Mann-Whitney u test was used. Receiver operating characteristic (ROC) curve analysis was used to calculate the sensitivity of SUR for predicting the salivary gland damage. Results: The SUR in dysfunctional parotid glands (n = 12) was significantly higher than that in other glands with normal function (n = 30; 3.60 (2.55, 4.33) vs 2.75 (2.33, 3.29); z = -2.005, P < 0.05). The SUR was not different between submandibular glands with lower function (n = 15) and those with normal function (n = 27; z = -0.144, P > 0.05). The SUR of parotid glands (n = 32) in patients with parotitis was significantly higher than that in others (n = 16; 3.16 (2.53, 4.01) vs 2.49 (206, 281); z = -3.073, P < 0.05). The SUR of submandibular glands (n = 28) in patients with sialadenitis was significantly higher than that in others (n = 20; 4.43 (2.67, 7.61) vs 2.93 (1.92, 4.65); z = -2.740, P < 0.05). When 2.97 and 3.66 were selected as cutoff values, the sensitivities of SUR for predicting parotitis and sialadenitis were 59% (19/32) and 64% (18/28), respectively. Conclusion: Rx-WBS may play a role in predicting radiation damage to the salivary glands. (authors)