Objective To compare the set up errors derived from different registration methods of the X-ray volume imaging (XVI) system for radiotherapy in the treatment of middle/lower-segment esophageal cancer, and to provide a reference for radiation treatment of esophageal cancer. Methods We randomly selected 63 patients with middle/lower-segment esophageal cancer, and obtained their reconstructed XVI images at the first therapy to perform automatic registration with gray-value and bone registration methods. We acquired and compared the three translation errors (along x [left to right], y [head to feet], and z [front to back] axes) and three rotation errors (around the x, y, and z axes) derived from the two registration methods. Results Gray-value registration had significantly smaller translation errors along the x and z axes than bone registration (x azes t = −2.78, z azes t = −2.15, P < 0.05), but there was no significant difference along the y axes (P > 0.05). The rotation errors around the three axes were all smaller than 1°, and were smaller with gray-value registration than with bone registration, but without significant differences (P > 0.05). Conclusion We recommend gray-value registration for radiotherapy in the treatment of middle/lower-segment esophageal cancer. Manual verification or fine-tuning is recommended after automatic registration in clinical practice. Besides translation errors, rotation errors should also be paid attention to.

Concurrent chemoradiotherapy is the main treatment for locally advanced cervical cancer, and the incidence of vaginal injury is inevitable after radiotherapy. However, insufficient attention has been paid to the treatment and prevention of acute radiation-induced vaginal injury. Therefore, the mechanism, treatment and prevention of acute vaginal side effects after radiotherapy in cervical cancer were reviewed in this article, aiming to reduce the incidence of vaginal injury, complete the course of radiotherapy and improve the quality of life.

Objective:To investigate the effect of 25 hydroxyvitamin D [25 (OH) D] on postoperative parathyroid function in patients with papillary thyroid carcinoma (PTC) .Methods:426 patients who diagnosed as PTC and underwent at least total thyroidectomy plus central lymph node dissection (including lateral lymph node dissection) in Center of Thyroid and Parathyroid Surgery of West China Hospital, Sichuan University, from Jun. 2017 to Sep. 2019 were retrospectively analyzed. Among them, 313 were women and 113 were men, they were divided into vitamin D deficient (VDD) group ( n=297) and normal group ( n=129) according to preoperative 25 (OH) D levels ≤ 20ng/ml and > 20ng/ml. SPSS 23.0 statistical software was used for data processing. Pearson χ2 test or Fisher exact test were used to compare the incidence of clinical hypoparathyroidism, biochemical temporary and biochemical permanent hypoparathyroidism between the two groups. Univariate and multivariate logistic regression analysis were used to analyze the related factors of postoperative hypoparathyroidism between the two groups. Results:Preoperative 25 (OH) D level was significantly correlated with postoperative biochemical temporary hypoparathyroidism ( P=0.04, OR=1.11) . Compared with patients with adequate preoperative vitamin D, preoperative vitamin D deficiency increased the risk of biochemical transient hypoparathyroidism by 6.67 times ( P=0.03;OR=6.67) . There was no significant correlation between preoperative vitamin D deficiency and early postoperative clinical hypoparathyroidism (2.7% vs 3.9%, P=0.55) . Conclusion:Correction of vitamin D deficiency before operation may reduce the incidence of postoperative temporary hypoparathyroidism caused by 25 (OH) D deficiency.

Objective:To explore the clinical characteristics and prognosis of metastatic sites symptom as the first manifestation in esophageal carcinoma patients with stage T 1 and T 2, and to provide a reference for clinical practice. Methods:The clinical data of 50 esophageal carcinoma patients with stage T 1 and T 2 who had lymph node or distant metastasis as the first symptom in Anyang Tumor Hospital of Henan Province from November 2007 to December 2019 were retrospectively analyzed. Survival analysis was performed by using Kaplan-Meier method. Univariate analysis was performed by using log-rank test. Results:Among 50 patients with esophageal carcinoma, lymph node metastases as the first symptom were found in 42 cases and distant organ metastases as the first symptom were found in 8 cases. The 1-, 3-, 5-year overall survival rates of patients with stage Ⅰ-Ⅱ and stage Ⅲ-Ⅳ were 58.7%, 49.0%, 16.3% and 56.1%, 12.2%, 0, respectively, and there was no statistically significant difference in OS of both groups ( P = 0.094). The 1-, 3-, 5-year overall survival rates of patients with stage N 1 and stage N 2-N 3 were 63.5%, 34.7%, 17.3% and 52.2%, 11.9%, 0, respectively, and there was no statistically significant difference in OS of both groups ( P = 0.083). The 1-, 3-, 5-year overall survival rates were 64.6%, 30.5%, 18.3%, respectively in radiotherapy group and 38.2%, 0, 0, respectively in non-radiotherapy group, and there was a statistically significant difference in OS of both groups ( P = 0.008); the progression-free survival in radiotherapy group was better than that in non-radiotherapy group ( P = 0.028). The 1-, 3-, 5-year overall survival rates were 70.8%, 35.5%, 21.3% and 33.3%, 0, 0 and 35.4%, 0, 0, respectively in concurrent chemoradiotherapy group, radiotherapy group and chemotherapy group, and there was a statistically significant difference in overall survival among three groups ( P = 0.004). The results of univariate analysis showed that radiotherapy ( χ2 = 7.112, P = 0.008) and concurrent chemoradiotherapy ( χ2 = 10.940, P = 0.004) were the main factors affecting the prognosis. Conclusions:Lymph node and distant metastasis could occur in esophageal carcinoma patients with stage T 1 and T 2. Radiotherapy can prolong the progression-free survival time and concurrent chemoradiotherapy could benefit overall survival of these patients.

Objective To investigate the health status of employees in Guangdong gas stations and analyze the factors of occupational hazards. Methods According to the records of the provincial comprehensive information system, and the division of administrative regions, a random sampling method was used to detect 22 street gas stations in the town of Xixiang, Baoan District, Shenzhen, with 335 related employees included. The hazardous factors of volatile chemical compositions were analyzed, and the results of occupational health examinations of gas station workers were evaluated. Results The occupational hazards in the volatile organic components of each oil product at 22 gas stations were analyzed, and the results showed that they all met the national standards. The occupational health status was evaluated on all employees in the gas stations in this survey. Most of them did not find any occupational hazards, but the health status of the staff in the duty room was better than that of the staff beside the tanker. Conclusion The gas station workers were at the general occupational hazard risk, but occupational protection also needs to be strengthened. Regular inspection of oil and gas recovery devices is required to improve the airtightness. Regular occupational training should be conducted to further standardize vocational operation.

Objective:To examine the correlation factors of contralateral central lymph node metastasis in unilateral papillary thyroid carcinoma with lateral cervical lymph node metastasis.Methods:The clinical data of patients with unilateral papillary thyroid carcinoma who underwent total thyroidectomy and bilateral central lymph node dissection and ipsilateral cervical lymph node dissection from June 2016 to June 2018 at Department of Thyroid Surgery, West China Hospital, Sichuan University were analyzed retrospectively. A total of 317 patients, including 87 males and 230 females, aged (41.4±12.1) years (range: 16 to 75 years), were enrolled in this study. The risk factors of contralateral central lymph node metastasis were analyzed by χ 2 test and Spearman correlation analysis. Results:There were 116, 69, 269, and 181 cases of pretracheal lymph node, prelaryngeal lymph node, ipsilateral central lymph node and contralateral central lymph node metastasis, respectively, and 16 cases of skipping metastasis. Univariate analysis showed that contralateral central lymph node metastasis was associated with gender, maximum tumor diameter, capsule invasion, pretracheal lymph node metastasis, prelaryngeal lymph node metastasis, and ipsilateral central lymph node metastasis (all P<0.05). Spearman correlation analysis showed that male ( r s=0.162, P=0.004), maximum tumor diameter>10 mm ( r s=0.184, P=0.001), capsule invasion ( r s=0.135, P=0.016), pretracheal lymph node metastasis ( r s=0.394, P<0.01), prelaryngeal lymph node metastasis ( r s=0.272, P<0.01) and ipsilateral central lymph node metastasis ( r s=0.203, P<0.01) were independent correlation factors for contralateral central lymph node metastasis. Conclusion:For patients with unilateral papillary thyroid carcinoma with ipsilateral cervical lymph node metastasis, bilateral central lymph node dissection should be considered if male, tumor diameter>10 mm, capsule invasion, pretracheal lymph node metastasis, prelaryngeal lymph node metastasis, or ipsilateral central lymph node metastasis.

Objective:To examine the correlation factors of contralateral central lymph node metastasis in unilateral papillary thyroid carcinoma with lateral cervical lymph node metastasis.Methods:The clinical data of patients with unilateral papillary thyroid carcinoma who underwent total thyroidectomy and bilateral central lymph node dissection and ipsilateral cervical lymph node dissection from June 2016 to June 2018 at Department of Thyroid Surgery, West China Hospital, Sichuan University were analyzed retrospectively. A total of 317 patients, including 87 males and 230 females, aged (41.4±12.1) years (range: 16 to 75 years), were enrolled in this study. The risk factors of contralateral central lymph node metastasis were analyzed by χ 2 test and Spearman correlation analysis. Results:There were 116, 69, 269, and 181 cases of pretracheal lymph node, prelaryngeal lymph node, ipsilateral central lymph node and contralateral central lymph node metastasis, respectively, and 16 cases of skipping metastasis. Univariate analysis showed that contralateral central lymph node metastasis was associated with gender, maximum tumor diameter, capsule invasion, pretracheal lymph node metastasis, prelaryngeal lymph node metastasis, and ipsilateral central lymph node metastasis (all P<0.05). Spearman correlation analysis showed that male ( r s=0.162, P=0.004), maximum tumor diameter>10 mm ( r s=0.184, P=0.001), capsule invasion ( r s=0.135, P=0.016), pretracheal lymph node metastasis ( r s=0.394, P<0.01), prelaryngeal lymph node metastasis ( r s=0.272, P<0.01) and ipsilateral central lymph node metastasis ( r s=0.203, P<0.01) were independent correlation factors for contralateral central lymph node metastasis. Conclusion:For patients with unilateral papillary thyroid carcinoma with ipsilateral cervical lymph node metastasis, bilateral central lymph node dissection should be considered if male, tumor diameter>10 mm, capsule invasion, pretracheal lymph node metastasis, prelaryngeal lymph node metastasis, or ipsilateral central lymph node metastasis.

Objective:To explore the application of ArcCheck system in the validation of Helical and Direct tomotherapy plans for esophageal cancer and summarize relevant experience.Methods:The Helical and Direct tomotherapy verification plans were established for 32 patients with esophageal cancer at different positions according to the doctor′s instructions, which were verified by the ArcCHECK system to compare the passing rate of the results.The correlation between the volume of the target area and the passing rate of the planned verification was analyzed. The therapeutic verification plan with a small target volume was made. The target area was placed at the center of ArcCHECK phantom and the area of detectors to statistically compare the verification passing rates.Results:Helical plan showed a significantly higher passing rate than the Direct plan ( P<0.01). The correlation coefficients between the target volume and the passing rate of the Helical and Direct plans were -0.364 and -0.042, and the P values were 0.041 and 0.819, respectively. For the Helical plan, when the 3%/2mm criterion was adopted, there was significant difference between placing the high-dose area at the center of the phantom and the area of detectors ( P=0.005), and the passing rate of the latter was higher. There was no significant difference in the other cases (all P>0.05). Conclusions:The passing rate of the Helical plan is generally higher than that of the Direct plan, which may be related to the angular response of the ArcCHECK detector and the fact that more reference points are not included for calculation due to low-dose radiation. In addition, it may also be related to the higher requirements of Direct plan for tomotherapy dose control system. In the Helical verification plan, when the 3%/3mm criterion is adopted, the larger the target volume, the higher the possibility of lower passing rate, whereas the correlation coefficient between them is relatively low. The high-dose area can be verified by the plans at the center of the phantom or the detection point. With the comprehensive consideration, we suggest putting it at the center of the phantom.

Objective To study the iodine nutritional status among the key population in Chenzhou City of Hunan Province,and to provide scientific basis for prevention and control of iodine deficiency disorders (IDD).Methods According to the "Hunan Iodized Salt Monitoring Pilot Scheme",total of 11 counties (cities,districts) were selected in Chenzhou City in 2015.One township was selected by east,west,south,north and center in each county (city,district).Four villages were drawn from each township,and 15 households were selected from each village to collect salt samples.Forty children aged 8 to 10 years old (half male half female) were selected from each primary school in each township.Urine samples were taken and the goiter was examined.Totally 20 pregnant women were selected from each township and urine samples were collected.The content of iodine in salt samples and urine samples were detected by the method of direct titration and As-Ce catalytic spectrophotometry,respectively.The status of goiter was detected using palpation.Results Totally 3 300 salt samples were detected in 2015,the median of salt iodine content was 25.2 mg/kg.The coverage and qualified iodized salt consumption rates were 99.61％ (3 287/3 300) and 95.30％ (3 145/3 300),respectively,which achieved the standard for the elimination of IDD.Totally 2 200 urine samples of children aged 8 to 10 years old were tested,the median of urinary iodine was 238.98 μg/L.There was variations of urinary iodine in children aged 8 to 10 years old in each county (H =32.25,P ＜ 0.01).Totally 2 200 children aged 8 to 10 years old were checked,and no goiter was found.Totally 1 100 urine samples of pregnant women were detected,the median of urinary iodine was 204.25 μg/L.There was variations of urinary iodine in pregnant women in each county (H =117.47,P ＜ 0.01).Conclusions Totally,the iodine nutritional status among the key population is appropriate in Chenzhou City.However,surveillance and health education should be continuously strengthened in the future.

Objective To analyze setup errors and guide the calculation of margins from clinical target volume (CTV) and planning target volume (PTV) in esophageal cancer patients treated with tomothcrapy by the MVCT image-guided system.Methods Sixty-four esophageal canccr patients trcated with tomotherapy in our hospital in 2016 were randomly selected.MVCT images were acquired after patients' positioning and co-registered with KVCT images.The setup errors of x,y,and z translations and roll rotation were analyzed with the t-test or one-way ANOVA.Meanwhile,PTV margin was calculated based on the formula of M =2.5 Σ + 0.7δ Results According to the formula,the CTV-PTV margins in the x,y and z directions are slightly different between cancers located in the cervical,upper thoracic,middle thoracic,and lower thoracic segments.In patients with upper thoracic esophageal cancer,the average setnp error in the yaxis was lower when the head-neck-shoulder thermoplastic film fixation was used than when somatic thermoplastic film fixation (P=0.000);the setup errors of z-axis with somatic thermoplastic film fixation in the fifth and sixth weeks were slightly less than those in the first several weeks (P =0.036);the setup errors acquired by three image registration patterns were similar (x-axis P=0.868,y-axis P=0.491,z-axis P=0.169,roll P=0.985).Conclusions In the treatment of patients with esophageal cancer,the setup errors are large,but the MVCT in the TOMO HD system can greatly reduce the setup errors,ensuring the accuracy of each treatment.It is further recommended that in clinical practice,different CTV-PTV margins should be used for the treatments of esophageal cancers located in different segments.Patients with upper thoracic esophageal cancer are advised to use the head-neck-shoulder thermoplastic film fixation.