Objective To investigate the differences in radiation dose during chest CT examinations among children of different age groups and establish dose estimation regression models. Methods Chest CT data from 135 children aged 4 to 15 years were retrospectively collected from the First Affiliated Hospital of Soochow University between January 2022 and December 2023. The children were divided into three age groups: 4-5 years, 6-10 years and 11-15 years. CT scanning parameters (tube voltage, tube current, scan range) and dosimetry parameters including volume CT dose index (CTDI_vol) dose length product (DLP), and size-specific dose estimate (SSDE) were recorded. The Kruskal-Wallis test was used to compare intergroup differences. A Pearson correlation analysis was performed to assess the relationship between age and dose indicators. Both linear and nonlinear regression models were constructed. Results Age showed a weak positive correlation with CTDI_vol (r = 0.27), a moderate positive correlation with DLP (r = 0.60), and a moderate negative correlation with SSDE (r = −0.55). Linear regression analysis revealed that DLP increased with age (y = 117.85 + 9.81x, R² = 0.36), while SSDE decreased with age (y = 12.4 − 0.18x, R² = 0.32). Using orthogonal distance regression, the goodness-of-fit of the nonlinear models for DLP and SSDE significantly improved (R² = 0.99 and 0.94, respectively). Conclusion In pediatric chest CT dose assessment, CTDI_vol underestimates radiation dose compared to SSDE and fails to account for patient body size. The dose estimation models constructed with orthogonal distance regression outperform those established using the least squares method, demonstrating higher fitting accuracy, and can serve as a reference for personalized dose management in pediatric CT examinations.

Objective To develop and validate risk prediction models utilizing five machine learning algorithms for assessing postoperative pulmonary infection(PPI)risk in lung cancer patients undergoing grade Ⅳ thoracoscopic surgery.Methods A retrospective cohort study included 2,380 lung cancer patients who underwent grade Ⅳ thoracoscopic surgery at a tertiary hospital in Shanghai(January 2022 to June 2024).Patients were stratified into training(n=1,665)and validation(n=715)cohorts.Five machine learning algorithms—Logistic regression(LR),artificial neural network(ANN),support vector machine(S VM),random forest(RF),and extreme gradient boosting(XGB)—were employed to construct predictive models.A nomogram was developed for clinical utility.Results Among 2,380 patients,226(9.5％)developed PPI.The Least Absolute Shrinkage and Se-lection Operator(LASSO)regression identified eight predictive variables:daily cigarette consumption,diabetes history,preoperative diffusing capacity,maximal tumor diameter,24-hour postoperative chest drainage volume,perioperative oral nutritional supplementation(ONS),postoperative urinary cathe-terization,and intraoperative pleural adhesion severity.All models demonstrated robust discrimina-tion,with area under the curve(AUC)values ranging from 0.862 to 0.947.The XGB model a-chieved superior performance(AUC=0.947,95％CI,0.937 to 0.962),followed closely by the LR model(AUC=0.926,95％CI,0.918 to 0.933).Conclusion Machine learning-based algo-rithms models effectively stratify PPI risk in lung cancer patients following grade Ⅳ thoracoscopic surgery.The derived nomogram provides a practical tool for perioperative risk management by healthcare providers.

Solar proton event(SPE)is the major concern for astronauts in space radiation environment.With the coming of solar activity peak of the 25th solar cycle,the frequency of occurrence of solar proton event is increasing,as well as the intense of the events.Two SPEs of the most flux in March 23rd,2024 and June 8th,2003 and one with extra-large geomagnetic storm in May 10th,2004 were used to analysis the astronaut dose both in China Space Station orbit and lunar environment.First,radiation particle spectrum outside TianHe module was used to calculate astronauts dose inside the station,which was compared with the measured dose;second,the fitting result of proton spectrum from GOES16 satellite was used to calculate astronaut dose in lunar orbit,which was compared with the dose measured by CRaTER.Besides,the change of dose with extra shield of different material was calculated.The results indicate when no extra-large geomagnetic storm occurs,middle level SPE has no influence to astronaut in station,but an obvious dose increase happens in lunar environment,approaching ten or more mGy in skin.When shielded by Al or water of 10g/cm2,the astronaut's dose could be reduced to mGy or below.Extra energetic protons would observe on station orbit when an SPE with extra-large geomagnetic storm occurs,however when the amount of energetic protons is small,the extra dose is about several 1 nGy to 1 μGy in skin,which was negligible compared with daily dose.When a middle or above level SPE occurs,the influence to astronaut in LEO needs judge immediately,which is mostly based on the geomagnetic activity,but extra shield are needed for manned lunar exploration to ensure astronaut safety.

Objective:To investigate the predictive value of thrombus enhancement (TE) and thrombus permeability in cardioembolic thrombus with acute middle cerebral artery occlusion based on CT.Methods:The clinical and image data of 93 patients with acute middle cerebral artery occlusion who were admitted to the First Affiliated Hospital of Soochow University within 12 hours after onset from January 2020 to July 2022 were retrospectively analyzed. According to the TOAST criteria, the patients were divided into the cardioembolism (CE) group (43 cases) and the large artery atherosclerosis (LAA) group (50 cases). All patients received noncontrast CT and CT angiography, and then thrombus permeability [thrombus attenuation increase (TAI), void fraction (ε)] and TE were assessed. Independent sample t-test, Mann-Whitney U test and χ2 test were used in univariable analysis between two groups. Multivariable logistic regression analysis was used to explore the independent influencing factors for cardioembolic stroke and establish a logistic model. The receiver operating characteristic (ROC) curve and the area under the curve (AUC) were used to evaluate the predictive value of TAI, ε, TE and the logistic model in cardioembolic thrombus with acute middle cerebral artery occlusion. Results:There were statistically significant differences in sex, atrial fibrillation, hypertension, diabetes mellitus, smoking, baseline National Institutes of health stroke scale (NIHSS), TAI, ε and TE between the CE group and the LAA group ( P<0.05). Binary logistics regression analysis showed that TAI (OR=1.300, 95%CI 1.147-1.473, P<0.001), hypertension (OR=0.116, 95%CI 0.025-0.535, P=0.006) and baseline NIHSS (OR=1.165, 95%CI 1.040-1.304, P=0.008) were independent influencing factors for cardioembolic thrombus. The ROC curve indicated that the logistic model predicted cardioembolic thrombus with the highest AUC of 0.907 (95%CI 0.848-0.966). TE predicted cardioembolic thrombus with the highest sensitivity of 90.7%. Conclusion:TE and thrombus permeability have application value for predicting cardioembolic thrombus with acute middle cerebral artery occlusion based on CT.

Humans ; Coronary Artery Disease/surgery* ; Percutaneous Coronary Intervention ; Heart ; Treatment Outcome ; Coronary Angiography

Background: Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster. The treatment of PHN remains a challenge for clinical pain management. Despite the effectiveness of anticonvulsants, antidepressants, and lidocaine patches in reducing PHN, many patients still face intractable pain disorders.In this randomized controlled study, we evaluated whether hydromorphone through intravenous patient-controlled analgesia (IV PCA) was effective in relieving PHN. Methods: Patients with PHN were randomly divided into two groups, one group received oral pregabalin with IV normal saline, another group received oral pregabalin with additional IV PCA hydromorphone for two weeks. Efficacy was evaluated at 1, 4, and 12 weeks after the end of the treatments. Results: Two hundred and one patients were followed up for 12 weeks. After treatment, numerical rating scale (NRS) score of patients in the hydromorphone group was significantly lower than that of the control group, and the difference of NRS scores between the two groups was statistically significant at 4 and 12 weeks after treatment. The frequency of breakthrough pain in the hydromorphone group was significantly lower than that in the control group 1 and 4 weeks after treatment.After treatment, the quality of sleep in the hydromorphone group was significantly improved compared with the control group. The most common adverse reactions in the hydromorphone group were dizziness and nausea, with no significant respiratory depression. Conclusions IV PCA hydromorphone combined with oral pregabalin provides superior pain relief in patients with PHN, which is worthy of clinical application and promotion.

Background: Postherpetic neuralgia (PHN) is the most common complication of acute herpes zoster. The treatment of PHN remains a challenge for clinical pain management. Despite the effectiveness of anticonvulsants, antidepressants, and lidocaine patches in reducing PHN, many patients still face intractable pain disorders.In this randomized controlled study, we evaluated whether hydromorphone through intravenous patient-controlled analgesia (IV PCA) was effective in relieving PHN. Methods: Patients with PHN were randomly divided into two groups, one group received oral pregabalin with IV normal saline, another group received oral pregabalin with additional IV PCA hydromorphone for two weeks. Efficacy was evaluated at 1, 4, and 12 weeks after the end of the treatments. Results: Two hundred and one patients were followed up for 12 weeks. After treatment, numerical rating scale (NRS) score of patients in the hydromorphone group was significantly lower than that of the control group, and the difference of NRS scores between the two groups was statistically significant at 4 and 12 weeks after treatment. The frequency of breakthrough pain in the hydromorphone group was significantly lower than that in the control group 1 and 4 weeks after treatment.After treatment, the quality of sleep in the hydromorphone group was significantly improved compared with the control group. The most common adverse reactions in the hydromorphone group were dizziness and nausea, with no significant respiratory depression. Conclusions IV PCA hydromorphone combined with oral pregabalin provides superior pain relief in patients with PHN, which is worthy of clinical application and promotion.

OBJECTIVE: To summarize the experience of perioperative prevention during double-lung transplantation for elderly patients with coronavirus disease 2019 (COVID-19). METHODS: Clinical data of 2 elderly patients with COVID-19 who underwent double-lung transplantation in the First Affiliated Hospital of Zhejiang University School of Medicine in March 2020 were retrospectively reviewed. Perioperative protective measures were introduced in terms of medical staffing, respiratory tract, pressure injuries, air in operating room, instruments and equipment, pathological specimens, and information management. RESULTS: Two cases of double-lung transplantation were successfully completed, and the patients had no operation-related complications. Extracorporeal membrane oxygenator was successfully removed 2 to 4 days after surgery and the patients recovered well. There was no infection among medical staff. CONCLUSIONS Adequate preoperative preparation, complete patient transfer procedures, proper placement of instruments and equipment, strengthening of intraoperative care management, and attention to prevention of pressure injury complications can maximize the safety of COVID-19 patients and medical staff.
Aged ; Betacoronavirus ; COVID-19 ; Coronavirus Infections ; Humans ; Lung Transplantation/standards* ; Pandemics ; Perioperative Care/standards* ; Pneumonia, Viral ; Postoperative Complications/prevention & control* ; Retrospective Studies ; SARS-CoV-2 ; Transplant Recipients

Objective To develop measurement methodology using film for the positioning accuracy of MLC leaves in IMRT.Methods The solid water phantom of 30 cm x 30 cm was scanned and the scanned images were transferred to TPS for treatment plan formulation.The five MLC strip picket fence pattern was formed by MLC leaves,each 3.0 cm long × 6.0 mm wide.The separation between strip and strip is 3.0 cm.SAD is 100 cm at dmax for 6 MV X-ray,with 250 MU per MLC strip.EBT2 radiochomic film was put on the phantom for delivery of IMRT,for each MLC strip.The present study focused on 30 accelerators of Varian,Elekta and Siemens designs at 27 hospitals with highly skilled physicists all over Jiangsu,Sichuan,Hubei and Henan provinces.The study was conducted in the same way as used in international multi-radiotherapy center (IMRC).The irradiated films were sent respectively to IAEA dosimetry laboratory and external audit group (EGA) of China for measurement,analysis and calculation.Results According to IAEA requirements,the differenc of film-measured and TPS-planned of MLC leaf position for each strip should be within ±0.5 mm.China had participated in the research of IMRC,with the result of 0.3,0.2,0.0,-0.1,and-0.2 mm,respectively.For 30 accelerators in four provinces involved in the study,the IAEA's verification results of MLC leaf position were within 0.6-1.0 mm for 5 accelerators and within ± 0.5 mm for other 25 ones.Whereas the verification results of EAG were within 0.6-1.0 mm for 6 accelerators and within ±0.5 mm for other 24 ones.According to IAEA requirements,the film-measured MLC leaf position deviation for each pair of leaves and average all pairs of leaves should be within ±0.5 mm.China had participated in IMRC's research,with the measured result being 0.04 mm.The verification result of EGA for 30 accelerators showed the measured MLC leaf position deviations were all ＜0.3 mm per strip,consistent with IAEA requirements.The IAEA's result showed the measured deviations of MLC leaf position for 29 accelerators were within ±0.5 mm,with only other one being-0.7 mm not consistent with the IAEA requirements.As required by IAEA,the difference of film-measured difference of MLC opening width should be within ±0.75 mm between each pair and average all pairs of leaves.China's result in research of IMRC showed the difference of minimum width to mean width was-0.2 mm whereas the difference of maximum width to mean width was 0.4 mm.For 30 accelerators involved in IAEA'verification study,the measured result shown that the difference between maximum and average of filmmeasured of MLC leaf width,and between minmum and average,were within ± 0.75 mm for 24 accelerators,in line with the IAEA requirements.For other 6 ones,the values were beyond ±0.75 mm,not in line with the IAEA requirements.For the verification result of EAG,the difference between maximum and average widths and between minmum and average widths for 25 accelerators were within ±0.75 mm as required by IAEA,whereas for other 5 ones the value were beyond ±0.75 mm,not consistent with IAEA requirements.The standard deviation of film-measured MLC opening width between each pair and average all pairs should be within 0.3 mm as required by IAEA.China's IMRC result was 0.12 mm.The verification result of IAEA shown the standard deviation of MLC opening position were ＜0.3 mm for 26 accelerators and ＞ 0.3 mm for other 4 accelerators.EAG verification result were the same as IAEA result.Conclusions The method using radiochromic film for measuring accuracy of MLC leaf position is convenient and practicable as a quality audit.It is suitable for quality verification in medical institutions owing to easy to post and repeated measurements.

Objective To verify the leaf positioning accuracy of multi-leaf collimator (MLC) in intensity modulated radiation therapy (IMRT) by using radiochromic films to provide references for IMRT quality control.Methods Medical linear accelerators of different designs,owned by 7 first-class hospitals at grade-3 in Hubei,were selected for this verification study.Five strip picket fence pattern was created by treatment planning system (TPS).Each strip was 0.6 cm wide with a 3 cm strip separation.MLC leaf positions,positioning bias and opening widths were then measured with EBT2 radiochromic films.Results According to IAEA standards,the film-measured and TPS planned MLC leaf position difference was ±0.5 mm.The difference of MCL strip position of No.5 and No.7 accelerator was 0.7 and-1.0 mm,respectively,not in line with the IAEA standards.The difference of film-measured MLC leaf position between each pairs and all pairs of leaves of 7 accelerators were all within ± 0.5 mm,in line with the IAEA requirements.As required by IAEA,the difference of opening width of MLC leave of each pair relative to the averaged widths of all pairs should be within ±0.75 mm.The filem-measured values from 7 accelerators ranged from-0.6 to 0.5 mm,all in line with the IAEA standards.Standard deviation of opening width of all leaves were required to be within 0.3 mm.The measured values from 7 accelerators ranged from 0.1 to 0.2 mm,in line with the IAEA standard.Conclusions The use of EBT2 radiochromic films to verify MLC leaf positioning accuracy is an important means of quality control owing to its simplicity and high measurement accuracy.It is recommended for verification use at a large scale.