[en] The gain-switching dynamics of low-dimensional semiconductor lasers is simulated numerically by using a two-dimensional rate-equation model. Use is also made of the ABC model, where the carrier recombination rate is described by a function of carrier densities including Shockley – Read – Hall (SRH) recombination coefficient A, spontaneous emission coefficient B and Auger recombination coefficient C. Effects of the ABC parameters on the ultrafast gain-switched pulse characteristics with high-density pulse excitation are analysed. It is found that while the parameter A has almost no obvious effects, the parameters B and C have distinctly different effects: B influences significantly the delay time of the gain-switched pulse, while C affects mainly the pulse intensity. (paper)

[en] Objective: To investigate the technique, efficacy and clinical significance of argon-helium cryoablation combined with bronchial artery infusion (BAI) for the treatment of advanced non-small cell lung carcinoma. Methods: Twenty patients, who met the requirements of this study, were divided into two groups. Patients in group A, were treated with argon-helium cryoablation only, whereas those in group B were treated with argon-helium cryoablation combined with BAI. Four week after the treatment, check-up CT scan or DSA were carried out. CT value of the tumor area both before and after the procedure was measured and compared.The clinical efficacy was evaluated based on the CT value, the parameters of CT perfusion imaging, RECIST criteria and the median survival time. Breslow method was used to figure out the median survival time and to draw the survival curves. Results: The coverage of spherical frozen region was over 90% in 80% patients (16/20). The difference was of no significance in the coverage between two groups (P > 0.05). The CT value of group A and group B was (16.73 ± 9.43) Hu and (15.29 ± 6.98) Hu, respectively, with no significant difference (P > 0.05). The blood flow (BF), blood volume (BV) and PS before the treatment were significantly different from that after the treatment in both group A and group B (P < 0.05). The difference in BV between two groups was statistically significant (P < 0.05). The therapeutic effect of group B was better than that of group A. During the follow-up period, 10 of the 20 patients died. The longest survival time was 20 months and the shortest survival time was 7 months, with the median survival time of 9 months in group A and 14 months in group B. By using Breslow method, the difference between two groups was of statistical significance (P < 0.05). The survival curves showed that the survival rate of group B was higher than that of group A. Conclusion: Argon-helium cryoablation combined with BAI is a safe and effect treatment for advanced non-small cell lung carcinoma, and its clinical efficacy is better than that of using cryoablation alone. CT perfusion imaging can reflex the changes after the operation, which is very helpful in accurately evaluating the therapeutic results. (authors)

[en] Objective: To compare the 3-month, 6-month and 12-month therapeutic efficacy of DSA-guided percutaneous injection of hypertonic glucose or ethanol combined with catheter directed drainage for the treatment of giant hepatic cysts. Methods: A total of seventy-three cases of single hepatic cysts with complete clinical data were retrospectively selected. Injection of hypertonic glucose was employed for sclerotherapy in 27 patients (group A), while sclerotherapy with ethanol injection was adopted in 46 patients (group B). Cyst diameters ranged from 8.3 cm to 15.8 cm. Under DSA guidance, puncturing injection of sclerotic agents and catheter directed drainage and aspiration were carried out for all lesions. The therapeutic efficacy at 3, 6 and 12 months were evaluated and the results were compared between the two groups. Results: The therapeutic procedure was successfully accomplished in all 73 cases. The puncturing success rate of the hepatic cysts was 100%. No significant difference in the 3-month, 6-month and 12-month therapeutic efficacy existed between the two groups, and the P values were 0.526, 0.713 and 0.613, respectively (P>0.05). Conclusion: In treating giant hepatic cysts with sclerotherapy, the 3-month, 6-month and 12-month therapeutic efficacy of using hypertonic glucose as sclerotic agent are not significantly different from those of using ethanol as sclerotic agent. As the use of hypertonic glucose carries less disagreeable feeling it is more suitable for the debilitated and aged patients. (authors)

[en] Objective: to assess the repeatability and consistency of magnetic resonance apparent diffusion coefficient (MR ADC) values of the completely remitted lesions of primary hepatocellular carcinoma (HCC) after TACE in order to provide a reference for clinical application. Methods: The MR ADC values of 21 completely remitted lesions were measured at 1, 3 and 6 months after TACE by the same radiologist (radiologist A) using the same sequence, which were measured again by another radiologist (radiologist B) one week later. By calculating the intra-class correlation coefficient (ICC) value and drawing Bland-Altman graph, the respectability and consistency of the ADC value measurement were evaluated. ICC values > 0.75 indicated good reliability and high repeatability. The consistency was considered to be enough high when 75% of the sites were located in the 95% confidence interval within the reference line on the Bland-Altman graph. Results: The ICC values measured by radiologist A 1, 3 and 6 months after TACE were 0.928, 0.878 and 0.934 respectively, which were 0.873, 0.940 and 0.871 respectively measured by radiologist B. The ICC values measured by radiologist A and radiologist B at different time one week before 1, 3 and 6 months after TACE were 0.854, 0.940 and 0.960 respectively, while the values were 0.788, 0.945 and 0.858 respectively one week after 1, 3 and 6 months after TACE. All the above values were greater than 0.75, indicating that the reliability was high. As 90% of the sites were located in the 95% confidence interval within the reference line on the Bland-Altman graph, the repeatability was regarded to be very high. Conclusion: The ADC values of the completely remitted lesions of HCC after TACE are quite stable. The measurements of ADC values for these lesions carry high degree of repeatability and consistency. With the help of ADC values, the stability of HCC lesions after TACE can be dynamically assessed and the therapeutic effectiveness can be promptly evaluated. (authors)

[en] Objective: To discuss the technique, efficacy and clinical significance of cryoablation combined with transcatheter arterial chemoembolization(TACE) for the treatment of advanced hepatic carcinoma. Methods: One hundred and ninety-two patients, who accorded with the selected criterion, were divided into TACE group (n=100) and combination group (cryotherapy combined with TACE, n=92). Pre-and post-treatment AFP level, recurrence rate and life span between two groups were compared. Results: The complete necrosis rate of the tumor and the recurrence rate in TACE group were 29% and 42%, which were 88.04% and 24% in combination group, respectively. The serum AFP level was significantly decreased after treatment in both groups (P<0.05), and the reduction in AFP level was significantly greater in combination group than that in TACE group (P<0.05). During a follow-up of 30 months the survival rate at each evaluation period of combination group was higher than that of TACE group without exception. Conclusion: As an effective and safe technique, cryoablation combined with chemoembolization is far superior to simple TACE in treating advanced hepatic carcinoma. (authors)

[en] Objective: To investigate the technique of argon-helium cryoablation and to assess its efficacy in the treatment of lung cancer. Methods: Sixty-eight patients with pathologically-proved lung cancer, who were admitted to the hospital between Jan 2006 and Jan 2008, were enrolled in the study. Both plain and enhanced CT scans were carried out one week before as well as one month after the cryoablation therapy. The maximum diameter and the average CT value of the tumor at the same cross section were measured and the results were compared. Thirty patients voluntarily took the CT perfusion examination, and the parameters were recorded and compared.The median survival time was calculated using Log-rank method. Results: The mean maximum diameter decreased from (5.61 ± 3.13) mm before cryoablation to (5.15 ± 3.00) mm after the operation. According to RECIST criteria, the improvement rate was 10.29% and the total efficacy rate was 98.52%. The average CT value at the section with maximum diameter was reduced from (42.01 ± 7.66) Hu before the procedure to (25.61 ±2.06) Hu after the procedure on plain CT scan, while the value was reduced from (66.99 ± 7.65) Hu to (29.66 ± 2.06) Hu on enhanced CT scan. The changes of CT perfusion parameters in 30 patients were as follows. (1) The blood flow dropped from (48.32 ± 8.41) ml/100 ml min before cryoablation to (28.73 ±8.92) ml/100 ml min after the operation. (2) The blood volume was reduced from (65.38 ±10.49) ml/1 000 ml to (37.8 ± 10.71) ml/1000 ml. (3) The time-to-peak was decrease from (13.08 ± 3.41) s to (10.01 ± 3.38) s. (4) The permeability was decreased from (91.79 ±22.80) ml·100 ml^-1·min^-1 to (44.62 ± 34.26) ml·100 ml^-1·min^-1. The differences between all the above results before and after the cryoablation treatment were of statistical significance. The median survival time of 68 patients was 13 months. Conclusion: Argon-helium cryoablation is a safe and effective treatment for lung cancer. CT perfusion imaging can help to make an early assessment of the therapeutic efficacy, and residual tumor as well as tumor recurrence can be promptly detected when a combination of CT perfusion imaging with other conventional examinations is employed, which is very important in guiding the clinical treatment. (authors)

[en] Objective: To investigate the probable mechanism and preventive strategies of cerebral lipiodol embolism caused by interventional therapy for hepatic tumor. Methods: The clinical data and the imaging materials of two cases occurred cerebral lipiodol embolism after interventional therapy for hepatic tumor were retrospectively analyzed, and the related papers in medical literature were reviewed. The common features of this condition were summarize and the probable mechanisms and preventive strategies were discussed. Results: A total of 17 cases who developed cerebral lipiodol embolism after interventional therapy for hepatic tumor have been reported in medical journals so far. Of the 17 cases, 15 have detailed clinical information. Together with our 2 cases, a total of 17 cases (13 males and 4 females) were involved in this study. The clinical and therapeutic data were summarized. In twelve cases the tumors were located at the dome of right liver and in the other two cases the tumors were located at other parts of the liver. Fifteen cases had massive tumor and two cases had other types of tumor. TACE was carried out in 16 cases and percutaneous intratumoral drug injection therapy was employed in one case. In 11 cases the used dose of lipiodol was over 20 ml. Pulmonary embolism occurred in 13 cases. No abnormal arterial-venous communications were found in 15 cases, while intra-pulmonary or intra-cardiac right-to-left shunt was detected in two cases. The clinical symptoms completely disappeared in 8 cases and were partly relieved in 6 cases. Three cases died. Conclusion: The occurrence of cerebral lipiodol embolism caused by interventional therapy for hepatic tumor may be relatde to the lipiodol dose and abnormal right-to-left shunt. Lesions located at liver dome and repeated TACE may be one of the potential risk factors. Control of lipiodol dose, use of lipiodol dose individually, preoperative evaluation of the presence of abnormal left-to-right shunt,selection of proper vessel for drug infusion and use of new embolic materials such as drug eluting beads, etc. may decrease the incidence of cerebral lipiodol embolism. (authors)

[en] La₃Ga_5.5Ta_0.5O₁₄ (LGT) crystal was grown by using the Czochralski method. The as-grown crystal is transparent, free from inclusions and with no cracks. Specific heat, thermal expansion, dielectric constants, transmission spectrum and optical damage threshold of LGT have been measured, and the results show general properties of LGT are similar to that of La₃Ga₅SiO₁₄ (LGS) crystal. The experiment to research the Q-switch properties of LGT has been performed and the results show LGT possesses smaller electrooptic coefficients than that of LGS and may not be an ideal material used as a Q-switch. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

[en] Objective: To explore the effect of hepatic function status (Child-Pugh classification) on the survival time in patients with advanced hepatocellular carcinoma after transcatheter arterial chemoembolization (TACE). Methods: TACE was carried out in 74 patients with advanced hepatocellular carcinoma. The clinical data were retrospectively analyzed. Based on the preoperative Child-Pugh grading, the patients were divided into Child-Pugh grade A group (n = 62) and Child-Pugh grade B group (n = 12). After the treatment all the patients were followed up. The correlation between the survival rate and the Child-Pugh grading was analyzed. Results: In Child-Pugh grade A group the survival rates at 3, 6, 9, 12 and 24 months after TACE were 85%, 60%, 31%, 17% and 11% respectively, while in Child-Pugh grade B group the survival rates at 3, 6, 9, 12 and 24 months after TACE were 33%, 17%, 17%, 8% and 0% respectively. The median survival time for all patients was 8.2 months. The median survival time for Child- Pugh grade A group and for Child-Pugh grade B group was 8.5 months (95%CI: 7.7, 9.3 months) and 2.5 months (95%CI: 2.4, 2.6 months) respectively (P = 0.002). Conclusion: Patients with advanced-stage hepatocellular carcinoma. if their hepatic functions are classified in Child-Pugh grade A, can get more benefit of a longer survival time from TACE. (authors)

[en] Objective: To evaluate the feasibility and value of dual-energy perfusion imaging (DEPI) of dual-source CT (DSCT) in the diagnosis of acute experimental pulmonary embolism. Methods Acute pulmonary embolism (PE) model was made in 8 New Zealand rabbits, and non-enhanced and enhanced DSCT scans were performed before and after embolization. Postprocessing of image data was made on the workstation, and CT pulmonary angiography (CTPA), DEPI and fusion images were obtained. The location and number of the lung lobes with pulmonary emboli were evaluated pathologically. Based on the pathological results, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CTA, DEPI and fusion images for the diagnosis of PE were calculated. Weighted Kappa values were calculated to evaluate the consistency between CTPA and DEPI. Results: PE model was made successfully in 7 rabbits. Six rabbits with 30 lobes were evaluated with one exception because of the catheter affecting the quality of lung perfusion image. PE was found pathologically in 18 lobar arteries. On DEPI, the region with PE showed low perfusion area comparing with the normal parenchyma and CTPA showed the filling defect within corresponding pulmonary artery or interruption of the artery. The sensitivity, specificity, PPV and NPV of CTPA were 66.7% (12/18), 100.0% (12/12), 100.0% (12/12) and 66.7% (12/18), respectively. The Kappa value was 0.651 indicating moderate correlation with pathology. The sensitivity, specificity, PPV, and NPV of DEPI were 88.9% (16/18), 91.7% (11/12, 94.1% (16/17) and 84.6% (11/13), respectively. The Kappa value was 0.795 indicating excellent correlation with pathology. Conclusion: Dual-energy lung perfusion imaging of DSCT can display the blood distribution of rabbit's lung and has a high sensitivity for the diagnosis of acute pulmonary embolism. (authors)