Objective To establish an optimal limiting dose for dose limiting rings placed in the anterior and posterior regions of the neck for reducing head and neck lymphedema under intensity-modulated radiation therapy(IMRT)for early nasopharyngeal carcinoma(NPC)from a dosimetric perspective.Method Fifteen newly diagnosed early-stage nasopharyngeal carcinoma patients who underwent CT localization for radiotherapy at the Cancer Hospital of Guangzhou Medical University from January to September 2022 were included in the study.Each case was designed with five sets of radiotherapy plans.Plan A consisted of conventional unlimited-field plans,while Plans B-E consisted of limited-field plans with dose constraints set at 20,18,16,and 14 Gy,respectively,with the remaining parameters consistent with Plan A.The impact on target coverage and organ-at-risk constraints was evaluated through variance analysis and pairwise multiple comparisons using a randomized block design to determine the optimal dose limits.Results The gradient of 16Gy was determined as the optimal dose limiting cutoff point for achieving the balance between target coverage and organ limiting dose.Compared with the conventional plan,The plans with the placement of a cervical anterior and posterior dose limiting ring(16Gy)did not change the target dose coverage(P>0.05),but only yielded a slight change in the homogeneity index(P<0.05).It did not cause any changes of the dosage in the inner ear,mandible,and brainstem(all P>0.05),but lead to statisti-cally significant reductions in the oral cavity,throat,and thyroid(all P<0.05).It caused a slight increase of the dose in the parotid gland and spinal cord(both P<0.05),but the increased dose was anyhow within the tolerance range.Conclusion The dosimetric investigation determines an optimal dose limit cutoff point for the cervical ante-rior and posterior dose limiting rings.It is expected to provide a design method for IMRT plans to reduce head and neck lymphedema after radiotherapy for early NPC.

Objective:To explore the differences in the clinical application of different brands of infrared ear thermometers in pediatric patients,and to guide the rational use of infrared ear thermometers.Methods:A total of 164 inpatients and outpatients who received treatment in the Children's Hospital of Zhejiang University School of Medicine from May 2023 to July 2023 were randomly selected,and three different brands of ear thermometers were used to measure the ear temperature of the children in the same measurement method.The differences in temperature and time measured by different brands of ear thermometers in children of different ages were compared.Results:The temperature and time measurements of the three ear thermometers were compared,the difference was statistically significant(F=5.007,264.988,P<0.05).The temperature of children aged≤3 months was measured by the three ear thermometers,and the difference was statistically significant(F=3.868,P<0.05).there was no difference in children aged over 3 months.Conclusion:For children of different ages,medical institutions can make choices based on the comprehensive consideration of the use cost,the speed of measurement time and other factors.For children aged over 3 months,choose product B with lower cost and faster measurement time,for children aged 0-3 months,it is recommended to choose product A with more accurate temperature measurement values.

OBJECTIVE：To esta blish a UPLC fingerprint of Pyrrosia petiolosa from southwest China ，and to determine the contents of 4 kinds of phenolic acids （neochlorogenic acid ，caffeic acid ，chlorogenic acid and cryptochlorogenic acid ）. METHODS：The determination was performed on Waters Cortecs T 3 C18 column（100 mm×2.1 mm，1.6 μm）with mobile phase consisted of methanol- 0.1％ phosphoric acid （gradient elution ）at the flow rate of 0.35 mL/min. The detection wavelength was set at 326 nm. The column temperature was 30 ℃，and injection volume was 1 μL. UPLC method was used to establish the UPLC fingerprint of P. petiolosa in combination with the Similarity Evaluation System of TCM Chromatographic Fingerprints （2012 edition）. Cluster analysis and principle component analysis （PCA）were performed by using SPSS 20.0 software. The contents of 4 kinds of phenolic acids in 20 batches of P. petiolosa were determined by external standard method. RESULTS ：There were 9 common peaks for the UPLC fingerprint of P. petiolosa . Peaks 1，3，4，5 and 9 were identified as neochlorogenic acid ，caffeic acid，chlorogenic acid ，cryptochlorogenic acid and isochlorogenic acid C ，respectively. RSDs of the relative retention time of each peak in different batches of P. petiolosa were 0-0.68％，and the RSDs of the relative peak area were 0-62.35％. The similarities between the fingerprint of 20 batches of medicinal materials and the control chromatogram were not less than 0.990. The result of cluster analysis showed that P. petiolosa from different regions could be sorted into three species. Results of PCA showed the differences among P. petiolosa from different regions. The linear range of neochlorogenic acid ，caffeic acid ，chlorogenic acid and cryptochlorogenic acid were 0.61-61.41，0.18-17.60，2.00-200.11，0.62-61.51 μ g/mL （R2＞0.999 9）. RSDs of precision ， reproducibility and stability tests were all lower than 2.00％. The recoveries were 96.23％-98.17％（RSD＝0.96％-2.28％， n＝6）. Among 20 batches of samples ，the contents of above 4 kinds of phenolic acids were 0.385 3-1.891 9，0.018 0-0.129 5，2.569 5-10.676 0，0.563.5-1.860 5 mg/g. CONCLUSIONS ： The established UPL C fingerprint could reflect the main chemical constituents of P. pedunculata . Phenolic acids could be used as the main evaluation indexes for the quality of P. petiolosa . The quality order of P. petiolosa from southwest China was Chongqing product＞Sichuan product ＞Guizhou product.