The Clinical Significance Of Radiation-induced Brain Injury Early Warning During Radiotherapy Of Nasopharyngeal Carcinoma On Somatosensory Evoked Potentials

Objective: The radiatiotherapy is a main treatment for patients with nasopharyngeal carcinoma and often causes radiation-induced brain injury, which usually has no early clinical symptoms and radiological abnormalities. In this study, we observe changes of SLSEP during the radiotherapy of patients with nasopharyngeal carcinoma by monitoring of the upper limbs short latency somatosensory potentials(SLSEP), further to explore the clinical value of early warning radiation brain damage, to guide radiotherapy programs, early intervention, and to reduce the severity of radiation-induced brain injury occurring.Methods: We select patients pathologically diagnosed NPC in our hospital radiotherapy department from October 2014 to March 2016, which meets the inclusion and exclusion criterias. Before radiotherapy,during radiotherapy,radiotherapy ending and 6 months after radiotherapy SLSEP examination were performed. N9 as monitoring potential,we observe the N9, N20 peak latency( PL), amplitude(Amp) and N9-N20 inter peak latency( IPL), and are going to self-control before and after the analysis. A total of 30 cases completed. While at the end of radiotherapy patients with nasopharyngeal carcinoma clinically suspected radiation-induced brain injury accept routine brain MRI,to comparative analysis with SLSEP.Result:1. In this study, we have completed a total of 30 cases, including 17 male patients and13 female patients, aged 28 to 72 years, average age(47.73 ± 14.65) years old.2. During radiotherapy, radiotherapy ending and 6 months after radiotherapy SLSEP abnormal rates are respectively 28.3%, 56.7%, 73.3%, Comparison of multiple samples rates, the difference is statistically significant(P<0.05);During radiotherapy,radiotherapy ending and 6 months after radiotherapy are compared with before radiotherapy, N20’s PL and N9-N20’s IPL are prolonged during radiotherapy, which the difference is statistically significant(P <0.05).3. In the 30 th day of radiotherapy, the total exposure dose of patients with nasopharyngeal is 46.2Gy, abnormal rate of SLSEP is 28.3%, while at the end of radiotherapy, a total exposure dose is 70 Gy, the error rate of SLSEP has increased to56.7%.3. According to the clinical diagnostic criteria of radiation brain damage: at the end of radiotherapy nasopharyngeal carcinoma patients suspected radioactive brain damage,the total of patients 13 cases accept routine brain MRI, sequence on T1 Wl, T2 WI,FLAIR, there were no obvious abnormalities on the resultant image signal,however,their SLEEP were abnormal, showing N9-N20 peak interval prolongation,accompanied by varying degrees N20 amplitude changes, the performance of N20 amplitude flat, incomplete differentiation.Conclusion:1. Nasopharyngeal carcinoma patients after receiving radiatiotherapy can damage normal brain tissue, and somatosensory evoked potentials may reflect the existence of the early radiation of brain damage.2. The N9-N20 amplitude peak latency of SLSEP may be as the sensitive indicators and warning value early stage of radiation-induced brain injury, to early intervention,radiotherapy adjustment programs, early treatment, the overall increase in patients with nasopharyngeal carcinoma efficacy and quality of life, and provide clinicians with valuable information on clinical diagnosis; N9-N20’s IPL SLEEP can expect further quantitative research, which willl be a worthwhile research direction.