Objective To evaluate the ambient dose equivalent rates of photons and neutrons inside and outside the door of a 10 MV accelerator room, and to report the shielding effect of boron-containing polyethylene as maze wall lining. Methods The ambient dose equivalent rates of photons and neutrons inside and outside the door of an accelerator room were taken as the research subject. The Kersey, Falcão, and modified Kersey methods were used to calculate the ambient dose equivalent rates of neutrons and neutron capture gamma rays inside and outside the door of the room before and after renovation. Measurements were made using an X-ray/γ-ray dose rate instrument and a neutron ambient dose equivalent rate meter. Calculated and measured results were compared. Results Before renovation, the measured neutron dose rate inside the door was 409 μSv/h, while the calculated values were 323 μSv/h (Kersey method), 428 μSv/h (Falcão method), and 219 μSv/h (modified Kersey method). The Falcão method yielded a value closest to the measured value, while the Kersey and the modified Kersey methods underestimated the value by 21% and 46%, respectively. After the installation of boron-containing polyethylene plates, the measured neutron dose rate inside the door was 190 μSv/h, with a 54% reduction. The neutron and photon ambient dose equivalent rates outside the door were 5.8 μSv/h and 6.0 μSv/h, respectively, before renovation, and 0.14 μSv/h and 1.6 μSv/h, respectively, after renovation. Conclusion For a 10 MV accelerator room, neutron shielding and protection measurements are necessary, especially for rooms with short mazes. The Falcão method provides the best estimate of neutron dose rates inside and outside the door. Using boron-containing polyethylene plates as maze wall lining is an economical and effective shielding method.

Objective To analyze the layout and shielding effectiveness of medical accelerator vaults, and to provide a reference for the layout, shielding design, and optimization of protection of medical accelerator vaults. Methods Four medical accelerator radiotherapy vaults were selected. The layouts of these vaults were compared with the layout requirements in the radiation therapy protection standards. For each vault, the dose rates at four points of interest outside the shielding were calculated, including the primary shielding area, secondary shielding area, maze outer wall, and lateral shielding area. These values were then compared with the actual measurements obtained using a dose rate meter. Results All four vaults were located on the ground floor of the building and included a maze, with the auxiliary rooms all placed outside the treatment rooms. However, one vault was not located at one end of the building, and in another vault, the control room was exposed to direct irradiation of the useful beam. The calculated dose rates outside the primary shielding area ranged from 0.04 μSv/h to 0.62 μSv/h, while the measured values ranged from 0.10 μSv/h to 0.66 μSv/h, with the measured values being higher than the calculated ones. The calculated dose rates outside the secondary shielding area ranged from 0.0005 μSv/h to 0.12 μSv/h, those outside the maze outer wall ranged from 0.06 μSv/h to 0.18 μSv/h, and those outside the lateral shielding area ranged from 0.009 μSv/h to 0.15 μSv/h; the measured values were all below the detection limit. Conclusion Inadequate layouts were observed in some of the accelerator vaults. The calculated and measured dose rates at points of interest outside the vaults were both significantly lower than the shielding protection requirements in standards, indicating that the shielding designs were overly conservative. Construction units should follow the principle of optimization of radiation protection to design the layout and shielding reasonably and pay attention to the underestimation of dose rates outside the primary shielding caused by the tenth value layer.

Objective To evaluate the effect of a multidisciplinary collaborative quality control management (hereinafter referred to as "QC management") on improving the performance of biological safety cabinets in hospital. Methods A total of 63 ClassⅡbiological safety cabinets in active use at Peking University Third Hospital were selected as the study subjects using the before-after study mode. Conventional management was implemented on the biological safety cabinets from 2018 to 2021. QC management was used in 2022. The compliance of biological safety cabinets management norm and performance differences under the two models were compared. Results The median and the 25th and 75th percentiles [M(P₂₅, P₇₅)] of the service life among these 63 biological safety cabinets were 3 (1,6) years. The overall performance pass rate and inflow velocity pass rate of biological safety cabinets were higher in the QC management than that in the conventional management (90.5% vs 65.1%, 96.8% vs 84.1%, both P<0.05). However, there was no significant difference in downflow velocity, high-efficiency particulate air filter integrity, cleanliness, airflow smoke pattern, noise, and illumination pass rates of biosafety cabinets before and after the implementation of QC management (79.4% vs 88.9%, 90.5% vs 100.0%, 96.8% vs 100.0%, 85.7% vs 100.0%, 100.0% vs 100.0%, and 85.7% vs 96.8%, respectively; all P>0.05). Conclusion sQC management improves the standardization of biological safety cabinet management and key performance indicators in hospital.

Objective To investigate the effects of glutathiones-transferase (GST) T1, GSTM1 and epoxide hydrolase (EPHX1) genes on skin injury in workers exposed to coal tar pitch. Methods Workers from a carbon manufacturing company involved in coal tar pitch production and use were selected as the study subjects using a judgment sampling method. Workers with skin injury after exposed to coal tar were selected as the case group (55 cases), and those with the same workshop and type of work but without skin abnormalities were selected as the control group (197 cases). Urine and blood samples were collected from the workers, and levels of polycyclic aromatic hydrocarbon metabolites, including 1-pyrenol (1-OH-P), 1-naphthol (1-OH-N) and 2-naphthol (2-OH-N), in urine were measured using ultra high-performance liquid chromatography tandem mass spectrometry. The GSTT1, GSTM1 and EPHX1 genes in blood were detected by polymerase chain reaction. Results In the case group, all 55 workers reported skin stinging, 25 workers reported itching and flaking, and 15 workers reported blackheads and pigmentation. Urinary levels of 1-OH-N and 2-OH-N were lower in the worker in the case group than that in the control group (all P<0.05). However, there was no significant difference in the level of 1-OH-P between the two groups (P>0.05). There were significant differences in the number of workers with GSTT1, GSTM1 and EPHX1(His139His) genes between the two groups (all P<0.01). The GSTT1 and GSTM1 genes were positively correlated with post-shift urinary levels of 1-OH-N, 1-OH-P, and 2-OH-N (all P<0.01). The EPHX1 (139Arg locus) gene was positively correlated with post-shift 2-OH-N levels (P=0.03). The GSTT1, GSTM1, and EPHX1 (139Arg locus) genes were associated with reduced skin damage among coal tar workers (all P<0.01), after controlling for age, length of service, gender, smoking, and alcohol consumption. Conclusion Exposure to coal tar pitch can cause skin injury in workers, and the GSTT1, GSTM1, and EPHX1 (139Arg locus) genes are protective factors against skin injury in those workers.

Objective To analyze the medication rules of Professor HUANG Feng for the treatment of low back pain using data mining methods.Methods The information of prescriptions for the effective cases of outpatients with low back pain treated by Professor HUANG Feng were collected and screened.Microsoft Excel 2019 was used to analyze the frequency of medication and the distribution of properties,flavors and meridian tropism of the drugs in the included prescription.IBM SPSS Modeler 18.0 was used for association rule analysis,and IBM Statistics 26.0 was used for cluster analysis.Results A total of 239 prescriptions and 75 Chinese medicines were included.There were 23 high-frequency Chinese medicines with the medication frequency being or over 20 times,and the top 10 Chinese medicines were Glycyrrhizae Radix et Rhizoma,vinegar-processed Corydalis Rhizoma,Cibotii Rhizoma,Atractylodis Macrocephalae Rhizoma,Zanthoxyli Radix,salt-processed Achyranthis Bidentatae Radix,Rehmanniae Radix,Dipsaci Radix,Coicis Semen,and Salviae Miltiorrhizae Radix et Rhizoma.The medicines were mainly warm in nature,and were sweet,bitter and pungent in flavor.Most of the drugs had the meridian tropism of liver,stomach and spleen meridians.Among the drug combinations obtained from association rule analysis with the top 20 highest support,vinegar-processed Corydalis Rhizoma,Cibotii Rhizoma,Atractylodis Macrocephalae Rhizoma and Zanthoxyli Radix were the core drugs.Cluster analysis yielded 6 clustering combinations.Conclusion For the treatment of low back pain,Professor HUANG Feng follows the principle of"treatment adapting to the climate,individuality,and environment"and"treating the root cause of the disease",usually adopts the drugs for activating blood,moving qi and relieving pain,nourishing the liver and kidney,and also uses the medicines for replenishing qi and strengthening the spleen.The ideas of HUANG Feng for the treatment of low back pain can be used as a reference for the clinical treatment.

We reported a 32 years female patient in whom lung metastasis from breast cancer was presented as solitary pulmonary pure ground-glass opacity (GGO) lesion. The patient received rational preoperative examinations and surgery though the preoperative diagnosis was not accurate. Because of different therapy strategies and purposes, it is crucial to make distinction of atypical metastases from primary cancers. Thus, for patients with a history of malignancy, possible metastasis should be taken into consideration if new GGO was found on the CT. Besides this, the follow-up interval of CT should be shortened appropriately, preoperative examinations and surgical procedures should be made according to the suggestions of multidisciplinary team.

Objective To compare the effects of two arc(TA)and dual arc(DA)techniques on the dose distribution to the planning target volume(PTV)and organs at risk(OAR)in volumetric modulated arc therapy(VMAT)for lower mid-thoracic esophageal cancer.Methods Ten patients with lower mid-thoracic esophageal cancer who received radiation therapy at some hospital from July 2020 to June 2022 were selected retrospectively.A TA radiation therapy plan and a DA radiation therapy plan were developed for each patient using the Ray Arc module of RayStation 4.7.5.4 planning system,and the two kinds of radiation plans were compared in terms of dosimetric parameters including D2,D5,D50,D95,D98,homogeneity index(HI),conformity index(CI),beam-on time and total monitor unit for PTV and lung V5,V10,V20,V30 and Dmean and heartV30,V40 and Dmean and spine cord Dmax for OAR.SPSS 22.0 was used for statistical analysis.Results TA and DA radiation therapy plans had no significant differences in PTV CI,HI,D2,D5,D50,D95 and beam-on time(P＞0.05),and DA plan had D98 and total monitor unit higher obviously than those of TA plan(P＜0.05).In terms of OARs protection,DA plan had heart V30,V40 and Dmean slightly lower than those of TA plan with non-significantly differences(P＞0.05),while lung V5,V30 and Dmean and spine cordDmax significantly lower(P＜0.05).Conclusion DA technique gains advantages over TA technique in PTV dose distribution and dose to OAR,and the involvement of DA technique in preparing the VMAT plan for esophageal cancer contributes to enhancing the treatment efficacy.[Chinese Medical Equipment Journal,2024,45(1):62-66]

Objective Viral encephalitis is an infectious disease severely affecting human health.It is caused by a wide variety of viral pathogens,including herpes viruses,flaviviruses,enteroviruses,and other viruses.The laboratory diagnosis of viral encephalitis is a worldwide challenge.Recently,high-throughput sequencing technology has provided new tools for diagnosing central nervous system infections.Thus,In this study,we established a multipathogen detection platform for viral encephalitis based on amplicon sequencing. Methods We designed nine pairs of specific polymerase chain reaction(PCR)primers for the 12 viruses by reviewing the relevant literature.The detection ability of the primers was verified by software simulation and the detection of known positive samples.Amplicon sequencing was used to validate the samples,and consistency was compared with Sanger sequencing. Results The results showed that the target sequences of various pathogens were obtained at a coverage depth level greater than 20×,and the sequence lengths were consistent with the sizes of the predicted amplicons.The sequences were verified using the National Center for Biotechnology Information BLAST,and all results were consistent with the results of Sanger sequencing. Conclusion Amplicon-based high-throughput sequencing technology is feasible as a supplementary method for the pathogenic detection of viral encephalitis.It is also a useful tool for the high-volume screening of clinical samples.

Objective:To evaluate the safety and efficacy of domestically produced magnetic sphincter augmentation (MSA) for gastroesophageal reflux disease.Method:This study is a prospective cohort study. Patients with typical heartburn and reflux symptoms (at least partial response to proton pump inhibitors), abnormal esophageal acid exposure and normal esophageal peristalsis were included, prospectively in the Department of Gastroesophageal Surgery, Rocket Force Characteristic Medical Center from June 2019 to September 2022. Patients with hiatal hernia >2 cm and severe esophagitis were excluded. The MSA was wrapped around the distal esophagus after esophageal hiatus repair by laparoscopy. A postoperative questionnaire survey was conducted to assess the relief of symptom, complications, the discontinuation rate of proton pump inhibitor, and surgical satisfaction. Gastroscopy, high-resolution esophageal pressure measurement, and pH value impedance monitoring were also reviewed. The pre- and postoperative rates were compared using the McNeinar χ2 test. Result:Currently, 23 patients with gastroesophageal reflux disease were enrolled and underwent MSA surgery. There were 20 males and 3 females, aged ( M (IQR)) 48 (14) years (range: 25 to 64 years). All cases were successfully implanted with MSA. Subjective indicators were followed for 17 (18) months (range: 14 to 53 months), while objective indicators were followed for 17 (1) months (range: 12 to 23 months). The postoperative gastrointestinal and extraesophageal symptom scores showed a significant decrease compared to preoperative levels as follows: the degree of subjective relief of overall digestive symptoms was 90 (20)% (range:0~100%), the degree of subjective relief of overall respiratory symptoms was 100(10)% (range: 10%~100%), the overall satisfaction rate was 83% (19/23), the proton pump inhibitor discontinuation rate was 70% (16/23). The proportion of esophagitis has decreased from 44% (10/23) to 9% (2/23) ( κ=0.169, P=0.039), The Hill grade of gastroesophageal valve morphology improved from 1 case of grade Ⅰ, 5 cases of grade Ⅱ, 10 cases of grade Ⅲ, and 7 cases of grade Ⅲ preoperative to 22, 1, 0, and 0 cases postoperative. The proportion of lower esophageal sphincter pressure below normal has decreased from 70% (16/23) to 35% (8/23) ( κ=0.170, P=0.012). There were 21 patients who restored normal esophageal acid exposure. Eleven patients had mild long-term dysphagia, but it didn′t affect their daily life. No postoperative device migration, erosion, or secondary surgical removal occurred. Conclusions:Laparoscopic implantation of the MSA device was safe and well tolerated. It can effectively control the symptoms of gastroesophageal reflux disease, reduce medication, restore normal cardia morphology and function, and esophageal acid exposure. The main postoperative complication was dysphagia, but it was relatively mild.

Objective:To evaluate the safety and efficacy of domestically produced magnetic sphincter augmentation (MSA) for gastroesophageal reflux disease.Method:This study is a prospective cohort study. Patients with typical heartburn and reflux symptoms (at least partial response to proton pump inhibitors), abnormal esophageal acid exposure and normal esophageal peristalsis were included, prospectively in the Department of Gastroesophageal Surgery, Rocket Force Characteristic Medical Center from June 2019 to September 2022. Patients with hiatal hernia >2 cm and severe esophagitis were excluded. The MSA was wrapped around the distal esophagus after esophageal hiatus repair by laparoscopy. A postoperative questionnaire survey was conducted to assess the relief of symptom, complications, the discontinuation rate of proton pump inhibitor, and surgical satisfaction. Gastroscopy, high-resolution esophageal pressure measurement, and pH value impedance monitoring were also reviewed. The pre- and postoperative rates were compared using the McNeinar χ2 test. Result:Currently, 23 patients with gastroesophageal reflux disease were enrolled and underwent MSA surgery. There were 20 males and 3 females, aged ( M (IQR)) 48 (14) years (range: 25 to 64 years). All cases were successfully implanted with MSA. Subjective indicators were followed for 17 (18) months (range: 14 to 53 months), while objective indicators were followed for 17 (1) months (range: 12 to 23 months). The postoperative gastrointestinal and extraesophageal symptom scores showed a significant decrease compared to preoperative levels as follows: the degree of subjective relief of overall digestive symptoms was 90 (20)% (range:0~100%), the degree of subjective relief of overall respiratory symptoms was 100(10)% (range: 10%~100%), the overall satisfaction rate was 83% (19/23), the proton pump inhibitor discontinuation rate was 70% (16/23). The proportion of esophagitis has decreased from 44% (10/23) to 9% (2/23) ( κ=0.169, P=0.039), The Hill grade of gastroesophageal valve morphology improved from 1 case of grade Ⅰ, 5 cases of grade Ⅱ, 10 cases of grade Ⅲ, and 7 cases of grade Ⅲ preoperative to 22, 1, 0, and 0 cases postoperative. The proportion of lower esophageal sphincter pressure below normal has decreased from 70% (16/23) to 35% (8/23) ( κ=0.170, P=0.012). There were 21 patients who restored normal esophageal acid exposure. Eleven patients had mild long-term dysphagia, but it didn′t affect their daily life. No postoperative device migration, erosion, or secondary surgical removal occurred. Conclusions:Laparoscopic implantation of the MSA device was safe and well tolerated. It can effectively control the symptoms of gastroesophageal reflux disease, reduce medication, restore normal cardia morphology and function, and esophageal acid exposure. The main postoperative complication was dysphagia, but it was relatively mild.