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 explore the clinical usefulness of low-dose dual-source CT (DSCT) angiography in detecting coronary artery anomaly (CAA) in patients with complex congenital heart disease (CHD). Methods A total of 615 consecutive patients with complex CHD who underwent DSCT angiography between 2008 and 2012 were retrospectively reviewed. According to the ultrasonic results, a total of 312 patients with tetralogy of Fallot (n=176 cases) or double outlet right ventricle (n=72 cases) or pulmonary artery atresia (n=64 cases) were included. Scans were divided into 3 groups: retrospective electrocardiogram (ECG)-triggered spiral scanning in 75 cases, prospective ECG?triggered spiral scanning in 158 cases, and prospective ECG?triggered high?pitch spiral scanning in 79 cases. The subjective image quality was evaluated with a four?point scale by two radiologists. Radiation dose values were calculated. Interobserver agreement in subjective image quality grading was assessed by using Kappa statistics. The scanning groups were compared with the Kruskal?Wallis test. Results The incidence of CAA was 8.0 %(25/312). CAA was detected in 7.9%(14/176)patients with tetralogy of Fallot, 8.3%(6/72)patients with double outlet right ventricle, 7.8%(5/64)patients with pulmonary artery atresia. In 76%(19/25)of the patients, the anomalous vessels were crossing the right ventricular outflow tract (RVOT). Thirty of 312 CT examinations were nondiagnostic (9.6%). Two radiologists acquired good agreement (Kappa=0.72,P<0.01). The median subjective image quality score of three scan groups was 3 (range 1—4). The score in high?pitch spiral scanning group was significantly lower than those in other two groups (H=29.1,P<0.01). Retrospective ECG?triggered scans had a median dose of 1.19 mSv(range 0.52—3.29 mSv), prospectively ECG?triggered scans had a median dose of 0.51 mSv(range 0.27—2.13 mSv), and prospectively ECG?triggered high?pitch spiral scans had a median effective dose of 0.30 mSv(range 0.18—0.62 mSv). The difference between groups was statistically significant (H=160.0, P<0.01). Conclusions DSCT angiography is a reliable diagnostic method for the assessment of CAA with complex CHD and low?dose prospectively ECG?triggered DSCT scan is the best choice.

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 explore the application of low-dose prospective ECG-triggering dualsource CT (DSCT) angiography in infants and children with Kawasaki disease (KD).MethodsNineteen children diagnosed of Kawasaki disease underwent low-dose prospective ECG- triggering DSCT angiography (DSCTA) with free breathing and transthoracic echocardiogram (TTE).The overall imaging quality was graded on a five-point scale. Interobserver agreement in subjective image quality grading was assessed by Kappa statistics.The location,number and size of the aneurysms and dilations were recorded and compared with those of TTE.Pearson correlation analysis was used to evaluate the agreement on measurements between DSCTA and TTE.The average effective dose of DSCTA in all 19 children was calculated.ResultsDSCTA was performed successfully in all 19 children.A total of 91.5 ％ (226/247) segments permitted visualization with diagnostic image quality. Fifteen patients were diagnosed with coronary artery lesions. A total of 28 aneurysms and 15 arterial aneurysmal dilations were detected by DSCTA,while 19 aneurysms and 13 arterial aneurysmal dilations were found by TTE.TTE failed to detect 9 aneurysms (2 in the distal right coronary artery,2 in the posterior descending artery,1 in the middle of left anterior descending artery,1 in the middle of left circumflex artery,2 in the distal of LCX and 1 in the obtuse marginal branch)and 2 arterial aneurysmal dilations (1 at the diagonal branch and 1 at obtuse marginal branch). The concordance of DSCTA and TTE in measurement of diameter and length of these aneurysms and aneurysmal dilatations are good (0.63 ± 0.20) and (0.58 ± 0.20) cm vs ( 1.49 ± 0.83 ) and ( 1.22 ± 0.66) cm ( r =0.989 and 0.965,P ＜ 0.05 ).There was a good agreement on overall image quality ( Kappa =0.87 ). The mean effective dose was(0.24 ± 0.08) mSv.ConclusionProspective ECG-triggering DSCTA with very low effective radiation dose is safe,reliable and more sensitive than TTE on diagnosing of coronary artery lesions,especially in the distal lesions,in infants and children with KD.

Objective To evaluate the feasibility of chest digital tomosynthesis(DTS)for lung lesion screening by comparing the effective dose of chest DTS with chest digital radiography(DR),low-dose MSCT and MSCT examinations.Methods The Fluke lung/chest phantom underwent posterior-anterior (PA),left lateral(LAT)chest DR and DTS with automatic exposure control technique.Using RTI DoseGuard and WinODS,the dose area product(DAP)and effective dose of PA,LAT and total DTS were calculated.CareDose technique was used for MSCT and low-dose MSCT scans,the dose length products (DLP)was acquired.According to the DLP to E(k)conversion coefficient in ICRP 103,the effective dose of low-dose MSCT and MSCT were calculated.Paired t test was used for comparison of the mean effective dose of DTS,DR and low-dose MSCT.Results The mean effective dose was 0.1 3 mSv for chest DR and 0.11 mSv for DTS examination.The mean effective dose of low-dose MSCT and MSCT scans were 1.13 mSv and 6.38 mSv.The effective dose of chest DTS was comparable to that of chest DR,and was approximately 1/10 and 1/60 times lower than that of low-dose MSCT and MSCT scans.There was no statistical difference between chest DTS and DR(t =3.514,P ＞0.01),and there was a significant difference between chest DTS and low-dose MSCT(t =178.769,P ＜0.01).Conclusion DTS is a new X-ray tomography which has the advantage of low radiation dosage in chest examination for lung lesion screening comparing with low-dose MSCT.

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 explore the clinical value of dual-energy CT angiography (DE-CTA) in the diagnosis of carotid cavernous fistula. Methods Fourteen patients suspected of carotid cavernous fistula underwent DE-CTA between Dec. 2008 and Feb. 2010. Image post-processing of DE-CTA was performed with the dedicated software to obtain bone-removal and non bone-removal images. Four experienced radiologists evaluated image quality of DE-CTA, the number, location and size of fistulae and dilation of cerebral veins. The bone-removal and non bone-removal images were compared for displaying of fistulae and other related lesions. Kappa test was used to test the consistency of image quality evaluation between two radiologists. The sizes of fistulae were measured with bone-removal DE-CTA images and non bone-removal DE-CTA images respectively and their results were compared by using student's t-test and the correlation test. Results Twenty-eight intracranial internal carotid arteries of 14 patients showed acceptable image quality. Fourteen cases were diagnosed as carotid cavernous fistula with both bone-removal and non boneremoval DE-CTA images. Two patients presented with bilateral lesions, while 7 patients presented with left lesions and 5 patients had right lesions. Totally, sixteen fistulae lesions were detected in 14 patients. The mean size of fistulae was (0. 36 ±0. 10) mm by bone-removal images, whereas (0. 35 ±0. 11 ) mm by non bone-removal images. There was no significant difference between the two methods ( t = 0. 29, P ＞ 0. 05 ),and good correlation was found between the two methods ( r = 0. 97, P ＜0.05). Thirteen dilated cerebral veins in 8 cases were found by bone-removal images versus 9 dilated cerebral veins in 6 cases by non boneremoval images. Conclusions Image post-processing of DE-CTA is a simple and useful method to identify carotid cavernous fistula. DE-CTA is also useful for therapeutic planning.

Objective To evaluate the diagnostic values of diffusion weighted MRI(DWI)and contrast-enhanced magnetic resonance imaging(CE-MRI)using gadolinium chelates in patients with brain abscesses.Methods Conventional TlWI,T2WI,fluid attenuated inversion recovery(FLAIR),DWI and gadolinium-enhanced MRI were performed in 49 patients with single cystic/solid brain lesions.Retrospective analysis of the DWI signals and enhancement characteristics of patients with brain abscesses(n=22)and with cystic/necrotic brain tumors(n=27)was performed; meanwhile,measurement of the ADC values of the necrotic areas was performed.DWI combined with conventional sequences (group Ⅰ),CE-MRI combined with conventional sequences(group Ⅱ),and DWI,CE-MRI and conventional sequences(group Ⅲ)were employed to calculate their sensitivity,specificity,positive predictive value,negative predictive value and accuracy; these results were compared with the pathological results.Results The high DWI signal was noted in 20 patients with brain abscesses,and low DWI signal in 24 patients with cystic/necrotic brain tumors.Evenly thin walls and a ring enhancement under enhanced scan were noted in 14 patients with abscesses and 12 patients with cystic/necrotic brain tumors.Most of the ADC values in patients with brain abscesses were significantly lower than those in patients with cystic/necrotic brain tumors(P＜0.05).The diagnostic sensitivity to brain abscess in group I,group Ⅱ and group Ⅲ were 90.9％,63.6％ and 95.5％,respectively; the difference was statistically significant between group Ⅰ and group Ⅱ(P＜0.05),and between group Ⅱ and group Ⅲ(P＜0.05),but not between group Ⅰ and group Ⅲ(P＞0.05).Conclusion DWI is more sensitive in detecting the brain abscess than CE-MRI,and the measurement of ADC values can provide valuable differential diagnostic information for patients with brain abscess and cystic/necrotic brain tumor.

Objective To study the development of medical imaging in Shandong province and identify existing problems. Methods 378 secondary hospitals and above were surveyed with questionnaires and other means for a general picture of their radiology departments. The survey covered medical imaging examinations, human resources and equipment configurations. Results The recent five years have found a rapid growth of a variety of medical imaging examinations, digital imaging in dominance, high-end equipments as the mainstream, sufficient staffing, shortage of high-level talents in these hospitals. Conclusion The medical imaging examinations should be regarded as justified and reasonable, the competence of hospital staff should be upgraded, and operation of medical imaging examinations should be normalized.