Objective To establish a method for quantitative analysis of tiny amounts of tritium in hydrogen below the detection limit of isotope ratio mass spectrometer. Methods Hydrogen was oxidized to produce water in a self-developed catalytic oxidation device filled with platinum hydrophobic catalyst. The effects of different experimental conditions on hydrogen conversion rate were investigated. The tritium concentration in the synthetic water was measured using a liquid scintillation counter. The tritium concentration in hydrogen was calculated according to the measurement of the synthetic water. Results When the flow rate of hydrogen was fixed, the conversion rate of hydrogen increased with the increase of the reaction temperature but increased and then decreased with the increase of the flow rate of oxygen. Hydrogen could be completely converted under optimal experimental conditions. The hydrogen samples with volumetric tritium concentrations in the range of 1 × 10⁻⁷ to 2 × 10⁻¹⁴ were converted to water at the reaction temperature of 110 ℃ and hydrogen/oxygen flow rate of 100 mL/min. The resulting water was measured using a liquid scintillation counter. The measurement accuracy was better than 2%. Conclusion This method can be used to measure hydrogen samples with tiny amounts of tritium below the detection limit of isotope ratio mass spectrometer. Our results provide data support for the calculation of the separation capacity of cryogenic distillation process.

Objective To present the initial practice of a novel procedure for the surgical treatment of inguinal hernia-"lateral approach single-incision laparoscopic totally extraperitoneal(L-SILTEP)repair"in certain specific situations.Methods The clinical data of 110 inguinal hernia patients who underwent L-SILTEP in the First Affiliated Hospital of Ningbo University,Shanghai General Hospital affiliated to Shanghai Jiao Tong University School of Medicine,and Shanghai East Hospital affiliated to Tongji University from June 2021 to March 2024 were collected retrospectively.Patients' demographics,surgical details,length of hospital stay,and postoperative outcomes were analyzed respectively.Results All surgeries were completed successfully and there was no conversion.The median surgical time was 55(41.25,70)mins and the intraoperative blood loss was 5(2,10)mL.In surgery,inferior epigastric artery injury occurred in 5 cases(4.5%)and spermatic cord injury occurred in 1 case(0.9%).The mean visual analog scale(VAS)scores pain assessment at 6,24,and 48 h after surgery were 3.0±0.8,1.9±0.7 and 1.1±0.4,respectively.The duration of hospital stay was(3.3±0.7)days.The most common postoperative complication was seroma,which occurred in 9 cases(8.2%).Additionally,extraperitoneal hematoma occurred in 1 case(0.9%)and scrotum effusion in 1 case(0.9%).Conclusions Generally,L-SILTEP is safe,feasible and effective.However,due to its advanced technique-demand,the application of L-SILTEP should be patient-specific and surgeon-specific.The successful implementation of this surgical procedure necessitates extensive training and meticulous attention to the surgical details.

Objective To compare the image quality of diffusion-weighted MR neurography (DW-MRN) of the tibial nerve and the common peroneal nerve prospectively using different motion probing gradients (MPGs).Methods A total of 21 healthy volunteers underwent DW-MRN at the knee (unilateral imaging) on a 3.0 T magnetic resonance system with unidirectional MPGs.The protocol included anteriorposterior unidirectional,right-left unidirectional,three-directional and six-directional MPGs.The apparent SNR and CNR of tibial nerve and common peroneal nerve were calculated.Three-dimensional MIP images of the nerves were evaluated blindly by two radiologists using a four-point grading scale on basis of entirety depiction and the signal intensity.Significance was determined by using Friedman and paired Wilcoxon tests.Results The SNR of tibial nerves on DW-MRN with anterior-posterior,right-left,three directional and six directional MPGs were 4.17 (2.70-5.65),4.35 (0.47-4.69),3.46 (2.27-4.62) and 3.30 (2.06-4.43),respectively.CNR were 0.61 (0.46-0.70),0.63 (0.36-0.73),0.55 (0.39-0.64) and 0.53(0.35-0.63),respectively.The scores of tibial nerve image quality were 4.0 (2.0-4.0),4.0 (3.0-4.0),2.5 (2.0-3.5),2.0 (1.0-2.5),respectively.Interobserver agreement was good and the Kappa value was 0.69 (P ＜ 0.05).The SNR of the common peroneal nerves on DW-MRN with anteriorposterior,right-left,three directional and six directional MPGs were 3.05 (2.30-4.20),3.05 (2.26-4.34),2.72 (1.84-13.80) and 2.68 (1.87-3.67),respectively.CNR were 0.51 (0.39-0.62),0.51 (0.39-0.63),0.46(0.30-0.86) and 0.46(0.30-0.57),respectively.The scores of the common peroneal nerve image quality were 3.5 (2.0-4.0),4.0 (2.0-4.0),2.0 (1.0-3.0) and 2.0 (1.0-2.5),respectively.Interobserver agreement was good and the Kappa value was 0.70(P ＜0.05).For SNR,CNR and nerve image quality of the tibial nerves and the common peroneal nerves,there were significant differences among different MPGs (x2 =215.01,215.01,60.49 and 182.82,182.82,60.22,respectively,P ＜ 0.05).SNR,CNR and nerve image quality of the tibial nerves and the common peroneal nerves on DW-MRN with unidirectional MPGs were better than those with three-directional and sixdirectional MPGs (Z =-6.90-4.03,P ＜ 0.05).The SNR and CNR of the tibial nerves on DW-MRN with right-left direction were better than those with anterior-posterior unidirectional MPGs (Z =-3.53,-3.41,P ＜ 0.05),but there was no significant difference of image quality between right-left and anteriorposterior directional MPGs (Z =-0.58,P ＞ 0.05).DW-MRN of the tibial nerves with three-directional MPGs was better than that with six-directional MPGs (Z =-3.00,-2.80,-3.92,P ＜ 0.05).There were no significant differences between right-left and anterior-posterior unidirectional MPGs,or between three-directional and six-directional MPGs of common peroneal nerves (Z =-1.94--0.31,P ＞ 0.05).Conclusions DW-MRN has capability to provide three-dimensional visualization of the tibial and common peroneal nerves,and the image quality with unidirectional MPGs is better than that with three or six directional MPGs.

Objective To evaluate the application of prospective ECG-gated dual source CT (DSCT) in patients with acute chest pain, and compare it's image quality and radiation dose with those of retrospective ECG-gated spiral scan. Methods Thirty consecutive patients (Group A, average HR ≥85 bpm) with acute chest pain were scanned with prospective ECG-gated scan and another 30 consecutive patients (Group B, average HR ≥85 bpm)were analyzed by retrospective ECG-gated scan. Tube voltage and tube current were adapted by the BMI of patients. MPR, MIP, CPR and VR were used to display pulmonary arteries (PA), thoracic aorta and coronary arteries (CA). Image quality as well as radiation dose were assessed in 2 groups. Qualitative image quality was compared with chi-square test between the two groups,while quantitative image quality [the image noise ( IN ), signal-to-noise ratio ( SNR ) and contrast-to-noise ratio(CNR)] and radiation dose were evaluated with x2 test and Student's t test. Results The proportion of valid coronary segments for diagnosis were 379/385 ( 98. 44% ) and 390/396 ( 98.48% ) respectively in Group A and Group B with no significant difference(x2 =0. 002,P =0. 961 ). The IN [( 16. 23 ±5.75)vs ( 16. 31 ±3. 32) HU] ,SNR (26. 85 ±9. 94 vs 24. 78 ±9. 91 ) and CNR (20. 99 ±9. 31 vs 18. 65 ±8. 72)showed no significant differences between 2 groups ( t = 0. 069,0. 908 and 1. 224, P ＞ 0. 05, respectively).The ED was on average ( 8. 37 ± 2. 69 ) mSv in Group A, whereas on average ( 20. 05 ± 5.52 ) mSv in Group B. There was a statistical difference between 2 groups ( t = 9. 401, P = 0. 000). Conclusion Low dose prospective ECG-gated DSCT angiography can show similar image quality as retrospective ECG-gated spiral scan with radiation dose.

Objective To evaluate the feasibility, accuracy and its clinical value of MRI-guided needle biopsy of lung lesions. Methods A total of 137 patients with pulmonary nodules or masses underwent lung biopsy in low-field open MRI equipped with iPath 200 optical tracking systems. Among them, 103 cases had solitary pulmonary lesion; the other 34 cases had multiple foci. The maximum diameter of the lesion was not smaller than 3.5 cm ( ≥ 3.5 cm) in 57 patients, between 1.5 cm and 3.4 cm( 1.5-3.4 cm) in 71 patients, not greater than 1.4 cm ( ≤ 1.4 cm) in 9 patients. Results The puncture success rate was 100.0% (57/57) for lesions ≥3.5 cm, 98.6% (70/71) for lesions 1.5-3.4 cm,77.8% (7/9) for lesions ≤1.4 cm and 97. 8% (134/137) for total cases, respectively. According to the pathological results, pulmonary lesions were malignant in 98 cases and benign in 39 cases. The sensitivity,specificity, accuracy, positive predictive value and negative predictive value of MRI-guided lung biopsy were 94.2%(98/104), 100.0% (33/33), 95.6% (131/137), 100.0% (98/98) and 84.6% (33/39),respectively. Conclusion MRI-guided needle biopsy of lung lesion can be performed precisely in a lowfield open MRI with a low risk of complications. As a supplement to US or CT-guided biopsy, it is worth further promotion and application.

Objective To explore the value of MR imaging-guided percutaneous lumbar discectomy and discolysis with oxygen-ozone mixture for treatment of posterolateral lumbar disc herniation via a new puncture approach of facet joint medial route. Methods All 114 lumbar intervertebral discs in 103 patients were diagnosed as posterolateral lumber disc herniation by CT or MRI, which were located at the levels of L3-4 in 5 cases, LA-5 in 87 cases and L5-S1 in 22 cases. The procedure was guided under 0. 23 T open magnetic resonance with iPath 200 optical tracking system. A 14 G MR-compatible needle was punctured into the disc center via a new puncture approach of facet joint medial route. The therapy steps were as follows: firstly, cut nucleus pulposus and inject 6 ml oxygen-ozone mixture of 60 μg/ml in the disc center;secondly, retreat the needle to the local prominence, cut prominent part and inject 6 ml oxygen-ozone mixture of 60 μg/ml. Thirdly, retreat the needle to the periradicular nerve root, inject 15 ml oxygen-ozone mixture of 40 μg/ml and 4 ml pain-block liquid. All patients were followed up at 3 days, 1 month, 3 months and 6 months after operation, evaluated for the effect of treatment with the modified Macnab criteria, and the results were compared with the χ2 test. Results All procedures were successfully performed. Intraoperative dural injury occurred in 5 cases. Postoperative infection of intervertebral space occurred in 2 cases. The clinical effective rate was 96. 1% (99/103), 84.5% (87/103), 94.2% (97/103), 95.1% (98/103)respectively at 3 days, 1 month, 3 months and 6 months after operation, and the differences were signifieant (χ2 = 12. 942, P = 0. 005 ) . Conclusion MR imaging-guided percutaneous lumbar discectomy and discolysis with oxygen-ozone mixture via facet joint medial route is a minimally invasive, safety and effective method for the treatment of posterolateral lumbar disc herniation.

Objective To explore the value of MR imaging-guided percutaneous cervical discectomy and discolysis with oxygen-ozone mixture for treatment of cervical disc herniation.Methods Eight herniated cervical discs in 7 patients were diagnosed by MRI, including 5 discs of lateral protruding type, 2 discs of paramedian protruding type and one disc of central protruding type.All patients underwent MR imaging-guided percutaneous cervical discectomy and discolysis with oxygen-ozone mixture.The procedures were guided by a set of 0.23 T open MR system mounted with iPath 200 optical tracking system.The herniated portion of the disc was punctured with a 14 G MR-compatible needle in the healthy side via anterolateral oblique route.The interventional steps were as follows; firstly, cut herniated part with percutaneous discectomy probe and inject 2ml oxygen-ozone mixture of 60 μg/ml; secondly, retreat the needle to the disc center, resect nucleus pulposus, and inject 2 ml oxygen-ozone mixture of 60 μg/ml.All patients were followed up for 6 months, with 4 patients by telephone and 3 patients in outpatient clinic.The effect of treatment was evaluated according to Williams postoperative assessment standard.Results All procedures were performed successfully.The clinical outcome was evaluated as excellent in 5 cases, good in 1 case and fair in 1 case.The total ratio of excellent and good was 85.7%.No serious complication occurred expect 1 case with intraoperative paroxysmal pain.Conclusion MR imaging-guided percutaneous cervical discectomy and discolysis with oxygen-ozone mixture was a safe, effective and minimally invasive method for the treatment of cervical disc herniation.

Objective To explore the optimal reconstruction windows in patients with heart rate (HR) over 91 (beats per minute) bpm, and to explore the feasibility of prospective ECG-gated DSCT coronary angiography.Methods Two hundred and thirty-two patients[body mass index (BMI):23-25 kg/m2, with stable HR, and average HR ≥91 bpm]with suspected or known coronary artery disease underwent retrospective ECG-gated DSCT coronary angiography.They were divided into 3 groups (A-C) according to the average HR of scanning.Images were reconstructed from 29% to 80% of the R-R interval in 3% increments.Two independent readers assessed the overall image quality by a five-point scale and determined the optimal reconstruction windows of each coronary segment and the ranges.Coronary arteries were segmented according to the guideline of the American Heart Association (AHA).The degree of interobserver agreement was determined by Kappa statistics.Results Three thousand three hundred and fortythree segments were considered to have diagnostic image quality in 232 patients.The ranges of optimal reconstruction windows of images were concentrated on 81%-61% and 51%-31%.In group A(91-95 bpm), there were 1183 segments in 83 patients, and the according proportions were 5.49%, 94.51%,respectively; In group B(96-100 bpm), there were 986 segments in 68 patients, and the according proportions were 0.20%, 99.80%, respectively; In group C(≥ 101 bpm), there were 1174 segments in 81 patients, and the according proportions were 0.17%, 99.83%, respectively.The optimal construction windows in 3274 segments out of 3343 segments in 232 patients were concentrated in 41%, ranged from 51%-31%.The image quality assessment in 3343 segments in 232 patients have a high inter-observe agreement (Kappa=0.883,P <0.05).Conclusion The optimal reconstruction windows of patients with stable HR(≥91 bpm) was concentrated in 41%, ranged from 51%-31%.When nothing except the window of data acquisition is considered, the prospective ECC,-gated DSCT coronary angingraphy can be used in patients with stable HR(≥91 bpm).

ObjectiveTo explore the value of low-dose gated dual-source CT(DSCT)in the diagnosis of interrupted aortic.arch.MethodsNine pediatric patients performed DSCT angiography and color Doppler flow imaging(CDFI)in the thoracic aorta and heart.All patients were operated.ResultsDSCT examination was finished in all patients with interrupted aortic arch.Nine patients were associated with ventricular septal defect(VSD),8 patients with patent ductus arteriosus(PDA),2 with bronchus artery dilation and 3 with abnormal origin of the coronary artery.Seven patients were diagnosed as interrupted aortic arch by CDFI,2 patients were diagnosed as truncus arteriosus and coarctation of the aorta respectively.All VSDs and PDAs were detected by CDFI.The diagnostic accuracy of DSCT and CDFI were 94.12%(32/34)and 82.35(28/34)respectively.Conclusion DSCT is a valuable imaging method for the diagnosis of pediatric interrupted aortic arch.

Objective To study the protective effect of bionics-pulsed electromagnetic field (BEMF) on the biomechanical property of the bones of Wistar rats. Methods Thirty-two 3-month-old female Wistar rats were divided into 4 groups (n=8 in each group). The 8 rats of group A (the control) were treated normally and received injections of saline in the same amount of drugs for the rats of other 3 groups. The rats of group B received injections of desamethasone (1 mg/kg, 2 intramuscular injections/week). The rats of groups C and D received injections of desamethasone in the same procedure as that of group B. In addition, the rats of group C received daily subcutaneous injections of calcitonin in the dosage of 2 IU/kg and those of group D were irradiated with BEMF once daily. The results of the 3 kinds of therapeutic procedures were observed 8 weeks later. Results After the irradiation of BEMF, the biomechanical parameters of the lumbar vertebrae and the femur were far higher in the rats of group D than in those of group B. Conclusion BEMF irradiation is effective to prevent the decrease of biomechanical properties of the bones of the rats.