Due to the characteristics of the insidious onset,difficult early diagnosis and high malignancy of pancrea-tic cancer,only a minority of patients still have the chance of surgical resection at the time of diagnosis.In recent years,chemotherapy-based preoperative neoadjuvant therapy has been increasingly applied to pancreatic cancer without distant metastases to help achieve tumor downstaging,increase RO resection rate and improve patient survival.A large number of clinical trials have proven the advantages of neoadjuvant therapy for pancreatic cancer,but there are still many issues to be gradually addressed by further research to reach a consensus.

Objective:To investigate the safety and efficacy of combining programmed death-1 (PD-1) with tyrosine kinase inhibitors (TKIs) in patients with advanced hepatocellular carcinoma (HCC) before liver transplantation(LT).Methods:The data of six males with a mean ± s. d. age of (57.5±4.3) years who were treated with PD-1 inhibitors combined with TKIs for advanced HCC before LT at Beijing You'an Hospital, Capital Medical University and the First Medical Center of Chinese PLA General Hospital were retrospectively analysed. The tumor stagings, the use of PD-1 inhibitors and TKIs with their discontinuation in pre-LT/post-LT liver function recovery durations, incidences of complication. The tumor recurrence and disease-free survival rates were determined on follow-up of these patients at outpatients clinics.Results:For the 6 patients included in this study, four patients were classified by the Barcelona Clinic Liver Cancer Staging (BCLC) as C and the China Liver Cancer Staging (CNLC) as Ⅲa, and two patients were classified by the BCLC staging as B and the CNLC asⅡb. The mean cycle of PD-1 inhibitor used was 5.5 (1-20), and the mean duration of PD-1 inhibitor discontinuation was 19.5 (12-45) days pre-LT. All patients who were treated with PD-1 inhibitors combined with TKIs reached the liver transplantation standard, and all successfully underwent orthotopic liver transplantation. The liver function recovered well without any serious complications post-LT. All the patients survived without developing any acute rejection or other complications. The follow-up time ranged from 8.2 to 27.3 months, with a median of 11.9 months. No patients had died, and 2 patients developed tumor recurrence. The median (range) tumor-free survival time was 10.9 (2.9-27.3) months.Conclusion:Patients with advanced HCC could benefit from combined PD-1 inhibitors with TKIs therapy pre-LT. There were no increased incidences of acute rejection and other complications post-LT.

Objective:To improve the quality of 18F-fluorodeoxyglucose (FDG) PET images at different acquisition times through deep learning (DL) PET image reconstruction methods. Methods:A total of 45 patients (20 males, 25 females; age (52.0±13.6) years) with malignant tumors and PET/CT scans from September 2020 to October 2020 in the Department of Nuclear Medicine of the First Hospital of Shanxi Medical University were included in this retrospective study. The short acquisition time 30 s/bed PET images from the raw list mode were selected as the input of DL model. DL image reconstruction model, based on the Unet algorithm, was trained to output imitated PET images with full dose standard acquisition time (3 min). The image quality evaluation and quantitative analysis were carried out for four groups of images: DL images, 30 s, 90 s, and 120 s images, respectively. The quality of PET images in four groups was evaluated using the five-point method. Liver background activities, lesions quantification parameters (maximum standardized uptake value (SUV max), mean standardized uptake value (SUV mean), standard deviation (SD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)), and first-order texture features (skewness, kurtosis, uniformity, entropy) were measured. Kappa test, χ2 test and one-way analysis of variance (least significant difference t test) were used for data analysis. Results:The image quality scores between four groups were highly consistent ( Kappa=0.799, P<0.001). The number of patients with scores≥3 in DL, 30 s, 90 s and 120 s groups were 6, 4, 7 and 8, respectively ( χ2=125.47, P<0.001). The liver SD of DL group was significantly lower than that of 30 s group (0.26±0.07 vs 0.43±0.11; F=3.58, t=-7.91, P<0.05). The liver SNR of DL group was higher than that of 30 s group (11.04±4.36 vs 5.41±1.41; F=10.22, t=5.40, P<0.05). The liver SD and SNR of DL group were similar to those of 90 s group (0.39±0.16, 8.46±3.34; t values: -0.87 and 2.17, both P>0.05). In 18 tumor lesions with high uptake, SNR and CNR of DL group were significantly higher than those of 30 s group (60.21±29.26 vs 38.38±16.54, 22.26±15.85 vs 15.41±9.51; F values: 13.09 and 7.05; t values: 5.20 and 4.04, both P<0.001). There were statistically significant differences among four groups in the first-order texture features ( F values: 4.30-9.65, all P<0.05), but there was no significant difference between DL group and 120 s group ( t values: from -1.25 to 0.15, all P>0.05). Conclusion:DL reconstruction model can improve the quality of short-frame PET images, which meets the needs of clinical diagnosis, efficacy evaluation and radiomics research.