Objective To investigate the data of outpatient children,survey on the clinical characteristics of vertigo and provide baseline information for clinical diagnosis and treatment.Methods The questionnaires and clinical tests data of 553 children with vertigo were retrospectively analyzed.Results All the children and their parents received interviews,otological examinations and clinical audiological tests. Their ages were between 4 and 15,with the average at 9.51?2.83. ①The males were 341(61.66%) and female 212 (38.34%),with the gender ratio of male to female as 1.61:1. ②The peak of the age curves of treatment and the first onset of vertigo was 9.51 and 8.62-year-old,respectively. ③20.98% of children with vertigo had normal results with peripheral vertigo more common in the rest.④The semicircular canals were more likely to dysfunction if their relatives had vertigo or car sickness.Conclusion The age of children mostly with vertigo is between 6 and 11 years with more males than females. Vertigo itself can be a symptom but on the other hand,some show no positive signs even with vertigo.

Magnetic resonance imaging (MRI) simulator (MRI-Sim) can provide superior images for radiotherapy.Due to the complexity of MRI technology and the safety problem caused by strong magnetic field, the acquisition and implementation of MRI simulation is more complicated than CT simulation.In order to ensure the introduction of MRI-Sim, this paper reviews the selection, installation, and acceptance test of MRI-Sim, including the selection of host and auxiliary equipment, installation site preparation, and safety precautions,as well as MRI-Sim acceptance test and commissioning.

Objective:Continuous acquisition of swallowing images of head and neck cancer patients by using MRI technique was performed to observe and measure the movement regularity and maximum displacement of the soft palate, tongue and larynx.Methods:From July 2018 to October 2018, 20 patients with primary head and neck cancer were chosen randomly, 17 male and 3 female. The median age was 58.5 years (28 to 78 years). Among the 20 patients, 7 patients were diagnosed with nasopharyngeal carcinoma, 3 patients with oral cancer, 5 patients with oropharyngeal cancer, 3 patients with hypopharyngeal cancer, and 2 patients with nasal and paranasal sinuses cancer. Two patients were classified as stage Ⅰ-Ⅱ, 8 patients as stage Ⅲ and 10 patients as stage Ⅳ according to the eighth edition of AJCC.Results:The displacement of the upward movement of the soft palate during swallowing was (1.06±0.31) cm and followed the pattern normal distribution. The displacement of backward movement of the soft palate was (0.83±0.24) cm, which also almost normally distributed. The displacement of backward tongue movement was (0.77±0.22) cm and followed the normal distribution pattern. The displacement of upward tongue movement was 0 in patients with tongue depressor for image acquisition. The mediandisplacement of upward tongue movement in patients without tongue depressor was 1.23 cm (0.59 to 1.41 cm). The displacement of upward laryngeal movement was (1.14±0.22) cm and followed the normal distribution pattern, and the median displacement of forward laryngeal movement was 0.4 cm (0.27 to 0.90 cm).Conclusions:Swallowing movement may occur in head and neck cancer patients during radiotherapy. It can also cause the movement of gross tumor volume (GTV) and surrounding normal tissues. Therefore, extensive attention should be paid to the individual distance between GTV and planning gross tumor volume (PGTV) when making radiotherapy plans, aiming to ensure the prescription dose of cancer.