The Relationship Between The Salivary Glands Function And The Dose-volume Effect In Nasopharyngeal Carcinoma Patients With Intensity Modulated Radiation Therapy

Objective: To study the relationship between the salivary glands function and the dose-volume effect on nasopharyngeal carcinoma(NPC)patients with Intensity Modulated Radiation Therapy(IMRT).Method: Between October 2012 and June 2015,24 patients aged 46-68 with nasopharyngeal carcinoma treated with IMRT at our hospital were included in the research.There are 3 patients in stage ?,7 patients in stage ?,8 patients in stage ?,6 in stage ?_A based-on Fuzhou 1992 Staging System.Patients in stage? and ?A were treated with radiotherapy,while stage ?_B,?and ?_A were treated with radiotherapy and chemotherapy.The functional assessment of the salivary glands in 24 NPC patients was examined by MRI diffusion weighted imaging(MRI-DWI)at 1 week before radiotherapy,the 3 months,6 months,9 months after radiotherapy.Results:1 18 of 24 patients' symptom of dry mouth at the 9 months after radiotherapy were better than that at the end of radiotherapy.2 of 18 patients encountered grade1-0;5 of 18 patients experienced grade2-1;0 of 18 patients had grade2-0;6 of 18 patients experienced grade3-1;5 of 18 patients had grade3-2.6 of 24 patients' symptom of dry mouth has no difference compared at the 9 months after radiotherapy to at the end of radiotherapy.2 Compare the apparent diffusion coefficient(ADC)(×10-3mm2/s)of salivary glands measured in all 24 patients at the 9 months after radiotherapy :0-1grade symptom of dry mouth were totle 13 patients,these were measured the ADC(1.14±0.21);?2 symptom of dry mouth were totle 11 patients,these were measured the ADC(1.37±0.19).The result of two groups showed significant difference in anaesthesia.(P=0.014<0.05).3 Analyzed the factors about the symptom of dry mouth,we found that the primary factors were mean dose and V40.The independent hazards were mean dose and V40.We suggested that the dose?30Gy and volume V40?30% is for the preservation of salivary glands function.Conclusions:1 It was the 9 months after radiotherapy that can improve the symptom of dry mouth.2 We suggested that the dose?30Gy and volume V40?30% is for the preservation of salivary glands function.3 The symptom of dry mouth could be evaluated by MRI-DWI.The salivary ADC evaluates the function of salivary glands and agrees with condition of the symptom of dry mouth.