Saliva Electrolyte Analysis Using ICP-OES in NPC Patients Following IMRT

Objectives: Saliva plays an important role in oral health. Different ions in saliva contribute to the pH of oral cavity, taste sensation and the de/remineralization of teeth. Many factors can affect the ion concentration of saliva, with radiation being one of them. This study aims to investigate the feasibility of using inductively coupled plasma-optical emission spectrophotometry (ICP-OES) for salivary electrolyte analysis in subjects with nasopharyngeal carcinoma (NPC) undergoing Intensity-Modulated Radiation Therapy (IMRT) which is considered more superior in preserving salivary gland function when compared with conventional radiotherapy.
Methods: To date, 20 subjects have been recruited from Queen Mary Hospital and Prince of Wales Hospital. Stimulated saliva were collected before IMRT as baseline and at follow-up appointments 1 month, 3 months, 6 months after IMRT. The parameters being measured include flow rate, pH, ion concentration with ICP-OES.
Results: According to the data to date, the subjects after IMRT showed significant changes in salivary flow rate and salivary pH. But no significant difference has been observed in the concentration of selected ions.
Conclusions: ICP-OES is a feasible method for measuring salivary ion concentration in NPC subjects undergoing IMRT, provided with careful pretreatment of saliva and calibration of the machine.