Comparison of effects of absolute scatter correction and relative scatter correction on image quality in PET reconstruction / 中华核医学与分子影像杂志

Objective:To study the impact of different scattering correction algorithms in the reconstruction of PET/CT images on image artifacts and the precision of quantitative parameters.Methods:The phantom as described in the National Electrical Manufacturers Association (NEMA) NU2 standard was filled with 18F. The background activity was fixed, and the activity of the solution in the spheres was adjusted to obtain several configurations, including the normal ratio group (4.08∶1) and the extreme ratio group (200∶1). The surface contamination group with the same ratio as the extreme ratio group contained a small radioactive source with different doses of 18F (74, 37, 3.7 and 0.37 MBq) placed at the surface of the phantom. PET/CT images of 30 patients (21 males, 9 females, age: (44.5±10.2) years) from Peking University Cancer Hospital & Institute between July 2012 and December 2021 were retrospectively analyzed, including 10 with normal images ( 18F-FDG) and 20 with abnormal images (10 with dislocation during acquisition, 10 with surface contamination). The images were reconstructed with relative and absolute scattering correction. The phantom was evaluated using the target to background ratio (TBR) and the artifact classification. CV as well as the artifact classification were used to compare the clinical image quality. Mann-Whitney U test and χ2 test were used to analyze data. Results:In the normal ratio group and the extreme ratio group, the TBRs of phantom images reconstructed with relative correction were significantly higher than those with absolute correction (normal ratio group: 3.30(1.94, 4.53) vs 2.72(1.56, 3.56); z=-2.20, P=0.028; extreme ratio group: 105.47(45.62, 162.82) vs 101.36(43.96, 155.57); z=-1.99, P=0.046). In the surface contamination group, with the increase of the activity of the small source, the artifact became more obvious, and the artifact classification score of absolute correction was significantly better than that of relative correction (1.5(1.0, 2.0) vs 2.5(2.0, 3.0); z=-2.00, P=0.046). In the 10 normal 18F-FDG PET/CT patients, the CVliver of the relative correction (9.67%(8.00%, 11.00%)) was significantly lower than that of absolute correction (11.00%(9.00%, 12.00%); z=-2.57, P=0.010), indicating the higher image quality of images with relative correction. In abnormal images, the image quality of absolute correction was significantly higher than that of relative correction with fewer and less severe artifacts (dislocation cases: 9/10 vs 4/10; χ2=5.50, P=0.019; surface contamination cases: 9/10 vs 4/10; χ2=5.50, P=0.019). Conclusions:The relative scattering correction is suitable for normal situations in clinical PET acquisition. However, with dislocation or surface contamination, the absolute scattering correction helps to reduce the artifacts and improve the image quality.

Protective effects of valproic acid on cardiac and cerebral injury in rats subjected to severe scalding combined with seawater immersion injury with delayed fluid replacement / 中国药房

OBJECTIVE To study the protective effects o f valproic acid on cardiac and cerebral injury in rats subjected to severe scalding combined with seawater immersion injury with delayed fluid replacement. METHODS The rats were divided into scalding+delayed fluid replacement group （group S ），scalding+seawater immersion+delayed fluid replacement group （group SS ）， scalding+seawater immersion+valproic acid+delayed fluid replacement group （group SSV ）according to random number table ，with 60 rats in each group. All groups were subjected to 35％total body surface area third-degree full-thickness scalding with boiled water. Group SS and group SSV were immersed in artificial ；seawater（30 min）immediately after scalding ，and group SSV was subcutaneously injected with valproic acid 300 mg/kg immediately after out of water. Sodium lactate Ringer ’s 0314-2279277。E-mail：125467374@qq.com injection was injected intravenously within 30 minutes according to 1/2 Parkland formula at 2 h after scalding in each group for delayed fluid replacement. The death time of rats was recorded ，and the average survival time and 24 h survival rate of rats in each group were calculat ed. Mean arterial pressure （MAP），heart rate （HR），respiration rate （RR），rectal temperature （RT），arterial blood pH ，arterial partial pressure of oxygen （PaO2），arterial blood partial pressure of carbon dioxide （PaCO2），HCO3－，creatine kinase MB isoenzyme （CK-MB）and neuron specific enolase （NSE）were detected before scalding ，at 0，2，5 h after scalding. The pathological changes of cardiac and cerebral tissue were observed. RESULTS The 24 h survival rate of group SS （55％）was significantly lower than that of group S （90％）， while that of group SSV （75％）was increased significantly ，compared with group SS （P＜0.05）. Compared with group S ，the levels of MAP ，RT，HR，pH，PaO2 and HCO 3－ in group SS were significantly lowered ，while the levels of CK-MB and NSE were increased significantly at 0，2，5 h after scalding ；the levels of PaCO 2 were increased significantly at 2，5 h after scalding ， while the levels of RR were decreased significantly at 0，2 h after scalding （P＜0.05）. Compared with group SS ，the levels of MAP，RT，HR，pH，PaO2 and HCO 3－ in group SSV were significantly increased ，while the levels of PaCO 2，CK-MB and NSE were decreased significantly at 2，5 h after scalding ；the level of RR was increased significantly at 2 h after scalding （P＜0.05）. At 2，5 h after scalding ，cardiac and cerebral injury of rats in group SS were aggravated significantly than that in group S ；cardiac and cerebral injury of rats in group SSV were relieved significantly than that in group SS. CONCLUSIONS After severe scalding combined seawater immersion injury ，hypodermic injection of sodium valproate could protect cardiac and cerebral function of rats ， improve vital signs and blood gas index ，prolong survival time and improve survival rate in rats.

Predictive value of 18F-FDG PET/CT radiomics for the PD-L1 expression level in lung adenocarcinoma patients / 中华核医学与分子影像杂志

Objective:To explore the predictive value of 18F-fluorodeoxyglucose (FDG) PET/CT radiomics for the programmed death ligand-1 (PD-L1) expression level in lung adenocarcinoma patients. Methods:A total of 101 patients (43 males, 58 females; median age 60 years) with histologically confirmed lung adenocarcinoma who received pre-treatment 18F-FDG PET/CT from January 2017 to January 2019 in Peking University Cancer Hospital were included retrospectively. There were 44 patients with positive PD-L1 by immunohistochemical assays, and 57 with PD-L1 negative. Patients were assigned to a training set ( n=71) and a validation set ( n=30). Clinical data, PET/CT radiomics parameters, conventional metabolic parameters, and observed CT characteristics of these patients were included in the models. The filter method and embedded method were used in feature selection. Models based on logistic regression, random forest, XGBoost and Light Gradient Boosting Machine (LightGBM) were trained and evaluated, and the optimal parameters to predict the PD-L1 expression as well as the area under curve (AUC) were attained. Results:All models had predictive ability in the prediction of PD-L1 expression, while LightGBM was more powerful than the others, with the precision for positive and negative predictions of 0.85 and 0.76, respectively. Incorporating clinical data and data derived from thin-section CT images (clinical data+ CT) into the LightGBM, the precision, recall and F1-score for positive and negative patients were 0.71, 0.67, 0.69 and 0.69, 0.73, 0.72, respectively, with the accuracy of 0.70 and the AUC of 0.79. As for clinical data+ PET, the precision, recall and F1-score for positive and negative patients were 0.79, 0.73, 0.76 and 0.75, 0.80, 0.77, respectively, with the accuracy of 0.77 and the AUC of 0.80. As for clinical data+ CT+ PET, the precision, recall and F1-score for positive and negative patients were 0.85, 0.73, 0.79 and 0.76, 0.87, 0.81, respectively, with the accuracy of 0.80 and the AUC of 0.83. Features with significant importance in the model (clinical data+ CT+ PET) were as follows: maximum standardized uptake value (SUV max), peak of standardized uptake value (SUV peak), CT_shape_Maximum2DDiameterSlice, PET_shape_Elongation, PET_gray level co-occurrence matrix (GLCM)_Correlation, etc. Conclusions:Incorporating clinical data, PET/CT radiomics features and conventional metabolic parameters, the PD-L1 expression can be effectively predicted, which help to assist the selection of patients who may benefit from the immunotherapy.

Production and purification of solid target PET nuclide 89Zr and its antibody labeling / 中华核医学与分子影像杂志

Objective:To produce the solid target nuclide 89Zr , and prepare the probe 89Zr-desferrioxamine (DFO)-Trastuzumab. Methods:The 89Y(p, n) 89Zr nuclear reaction was used for 89Zr production. 89Y target was irradiated by 20 μA proton in a medical cyclotron ( E=12.5 MeV) for about 1-2 h. 89Zr was purified from hydroxamate resin using 1 mol/L oxalic acid solution. The characteristic peak, radionuclide purity and radiochemical purity of 89Zr were determined by γ-ray spectroscopy. 89Zr-DFO-Trastuzumab probe was synthesized by the reaction of 89Zr-oxalate and DFO-Trastuzumab at room temperature, and the radiochemical purity was measured. Results:89Zr was prepared successfully for 11 times, and the production of 89Zr was 555-1 506 MBq, with production rate of (34.8±5.2) MBq·μA -1·h -1. After the purification (purification rate: 42%-87%), 227.2-991.6 MBq 89Zr was obtained, with the concentration of 1.0×10 6 MBq/L. The γ spectrum showed that the characteristic peak of 89Zr were 511 and 909 keV, and no impurities were found. The radionuclide purity and radiochemical purity were both close to 100%. 89Zr-DFO-Trastuzumab was successfully labeled with radiochemical purity more than 95%, and it was above 90% within 72 h in human serum albumin (HSA) solution. Conclusion:Through the self-designed target assembling, the solid target PET nuclide 89Zr with high quality and labeling are successfully achieved, which provides guarantee for the clinical application of the 89Zr drug.

Production, quality control and micro PET analysis of novel solid-target based radionuclide 64 Cu / 中华核医学与分子影像杂志

Objective To briefly retrospect the production and quality control of 64 Cu(n = 9) in Department of Nuclear Medicine of Peking University Cancer Hospital in order to provide useful information for the further production and application of this novel radionuclide. Methods 64 Ni(p, n) 64 Cu nuclide re-action was used for the 64 Cu production. Firstly, a new electro-planting device for 64 Ni planting was de-signed. HM-20 cyclotron was applied to irradiate the slice for 5-8 h. 64 CuCl2 was purified, collected and in-jected into normal mice. MicroPET was conducted to monitor the metabolism in vivo. Results A new type of electro-planting device was designed and assembled. The enriched 64 Ni target showed smooth, even, dense surface and without obvious pits and cracks. High specific 64 Cu (1.3-4.1 GBq) can be collected after radio-chemical purification. 64 Cu was finally dissolved in 0.01 mol/ L HCl with high radionuclide purity (over 99.97％). MicroPET of 64 CuCl2 in normal mice showed that the radioactivity was mainly accumulated in the liver. Conclusion A new and real-time observable device for 64 Ni electro-plating has been designed and successfully used in the production of 64 Cu with high specific activity.

Effects of oral fluid resuscitation with pyruvate-oral rehydration solution on the hemodynamic parameters and organ functions during shock stage in dogs with a 50% total body surface area full thickness burn / 中华外科杂志

<p><b>OBJECTIVE</b>To study the effect of oral fluid resuscitation with pyruvate sodium-glucose-electrolyte solution (PGES) on hemodynamics, organ functions and mortalities during shock stage in dogs with burn.</p><p><b>METHODS</b>In comparison of oral pyruvate sodium-glucose-electrolyte solution (PGES) with NaHCO₃-glucose-electrolyte solution (HGES), beagle dogs with intubation of the carotid artery, jugular vein and jejunum for 24 hours were subjected to a 50% total body surface area (TBSA) burn, and were divided into three groups: pure burn without fluid resuscitation (NR, n = 8), and two oral fluid resuscitation (each n = 10), in which dogs were given with Pry-GES (OP) or NaHCO₃-GES (OH) according to Parkland formula. The hemodynamic and organ functions were measured serially before burn and 2, 6, 8, 12 and 24 hours after burn at no anaesthesia state A. Twenty-four hours mortality rate following burn was also recorded.</p><p><b>RESULTS</b>Two hours after burn, the mean arterial pressure of NR, OH and OP group was (45 ± 8), (57 ± 8) and (80 ± 9) mmHg (1 mmHg = 0.133 kPa) respectively, which were significantly reduced (t = 16.967, 14.595 and 10.100, all P < 0.05) compared with those before injury ((42 ± 6), (144 ± 6) and (142 ± 6) mmHg respectively), the change of cardiac output, dp/dtmax of left ventricular contractility and intestinal mucosal blood flow had the same trend as the mean arterial pressure. The systemic vascular resistance and organ parameters (Cr, CK-MB, ALT and DAO) in all groups increased obviously (t = -46.894--2.465, all P < 0.05). All measurements of NR group kept worsening, and all died within 24 hours after burn; while those of two oral resuscitation groups had improved gradually (F = 0.001-1.600, all P < 0.05), OP group was significantly superior to OH group (F = 0.013-0.466, P < 0.05). At 24 hours after burn, 6 (6/10) survived in OP group, 4 (4/10) in OH group and 0 (0/8) in NR group.</p><p><b>CONCLUSION</b>The Pyr-GES may be superior to the standard NaHCO₃-GES in the improvement of hemodynamics and organ functions during oral resuscitation in dogs with 50%TBSA full thickness burn.</p>

The effects of sodium pyruvate Ringer solution on hemodynamic and organ functions during shock stage in dogs with a 50％ total body surface area full-thickness burn / 中华危重病急救医学

Objective To compare the effect of intravenous resuscitation with sodium pyruvate (Pyr) Ringer solution against lactated Ringer solution on hemodynamic and organ functions during shock stage in dogs with burn.Methods 28 Beagle dogs were subjected to 50％ total body surface area (TBSA) burn,and they were divided into three groups:burn injury without fluid resuscitation (N R,n =8),Ringer lactate solution(RL,n =10),and Pyr Ringer solution (RP,n =10).They were given intravenous fluid resuscitation according to Parkland formula 30 minutes after burn.The hemodynamics,organ functions and mortality were observed in conscious state before burn injury,and 2,6,8,12,24 hours after burn injury.Results Within 24 hours after burn,all the dogs in NR group died,and those in RL and RP groups were all alive.At 2 hours after burn,the mean arterial pressure (MAP),cardiac index (CI),dp/dt max of left ventricular contractility were significantly reduced in NR,RL and RP groups compared with those before injury [MAP(mmHg,1 mmHg =0.133 kPa):45.33 ± 7.78 vs.141.67 ± 5.98,91.33 ± 10.25 vs.142.33 ± 6.16,98.67 ± 9.54 vs.142.83 ±5.47; CI (mL·s-1·m-2):8.17 ±0.83 vs.48.34 ±3.33,16.84 ±2.17 vs.47.34 ± 1.67,19.00 ± 1.50 vs.47.34 ± 1.33; dp/dt max (mmHg/s):426.83 ± 51.91 vs.1 372.50 ± 39.61,594.00 ± 88.23 vs.1 363.83 ± 44.92,645.00 ±66.82 vs.1 395.83 ± 19.49,all P＜0.05],and the systemic vascular resistance (SVR) and alanine transaminase (ALT),creatinine (Cr),serum MB isoenzyme of creatine kinase (CK-MB),diamine oxidase (DAO) were significantly higher [SVR (kPa·s ·L-1):1 322.50 ±36.37 vs.281.45 ± 8.84,777.50 ±41.84 vs.289.72 ± 6.70,571.40 ±40.01 vs.286.27 ±8.66; ALT (U/L):89.50 ±4.11 vs.40.57 ±3.63,89.25 ±4.88 vs.37.92 ± 2.62,86.30 ±5.61 vs.38.47 ±3.50; Cr (μmol/L):75.62 ±4.61 vs.41.58 ±2.78,77.00 ±5.92 vs.46.55 ± 3.17,74.13 ±2.56 vs.45.65 ± 1.83; CK-MB (kU/L):13.122 ±0.282 vs.1.557 ±0.009,8.885 ±0.272 vs.1.497 ± 0.009,8.692 ± 0.180 vs.1.490 ± 0.005; DAO (kU/L):2.26 ± 0.14 vs.0.25 ± 0.02,1.50 ± 0.07 vs.0.25 ± 0.01,1.37 ± 0.07 vs.0.25 ± 0.02,all P＜0.05].All parameters in NR group kept on worsening till death,while hemodynamic and organ functions of two intravenous resuscitation groups were gradually improved,CI,SVR and DAO in RP group were significantly superior to those of RL group from 2 hours on after burn (all P＜0.05),and dp/dt max and CK-MB in RP group were significantly better than those of RL group from 6 hours on after burn [dp/dt max (mmHg/s):1 082.33 ± 63.59 vs.1 018.60 ± 47.36,CK-MB (U/L):7 898.70 ± 255.74 vs.8 438.70 ± 442.00,all P＜0.05],and MAP (mmHg) was significantly better than that of RL group at 6 hours (124.67 ± 9.39 vs.114.33 ± 9.16,P＜0.05),and Cr (tμmol/L) was significantly better than that of RL group from 24 hours on after burn (53.42 ± 4.99 vs.60.77 ± 3.11,P＜0.05).Conclusion The Pyr Ringer solution was superior to the Ringer lactate solution in improving hemodynamic and organ functions for intravenous resuscitation in dogs with 50％TBSA full thickness burn.