Objective To test image quality, accuracy of attenuation and scattering corrections of PET with NEMA NU2-2001. Methods By using NEMA IEC/2001 PET Phantom,along with the test methods recommended by NEMA NU2-2001, the PET image quality, accuracy of attenuation and scatter corrections were measured. Results Relative error in attenuation and scatter corrections were 0.25 (n=4) and 0.25 (n=8) respectively. Conclusion It's difficulty to prepare the phantom and process data. Preparing the phantom according to the radioactivity ratio strictly and processing data carefully even with many times, the exact result of the test can be obtained.

As the main means of mastication, teeth can withstand countless functional contacts. The mechanical properties of teeth are closely related to their tissue structure. Enamel and dentin have a high hardness and modulus of elasticity, and their graded structure allows them to withstand bite forces without being susceptible to fracture. When tooth tissue is defective, full crown restoration is often needed to restore the normal shape and function of the tooth. Metal materials, ceramic materials, and polyetheretherketone (PEEK) materials are commonly used for crown restoration. Metal materials have certain disadvantages in terms of aesthetics and are relatively rarely used in clinical practice. Ceramic materials with different compositions exhibit differences in performance and aesthetics, but their elastic modulus and hardness are much higher than those of dental tissue, resulting in mismatching mechanical properties. In contrast, the elastic modulus of PEEK is lower than that of tooth tissue and similar to that of bone tissue, but its properties can be improved by fiber reinforcement. Notably, when the mechanical properties of a restoration material and tooth tissue are not fully matched, the interface between them often forms a potential weak link, which ultimately affects the stability and long-term effect of the restoration. This article introduces the mechanical properties and corresponding structural characteristics of enamel and dentin. On this basis, the advantages and limitations of existing restoration materials are analyzed, and the possibility of biomimetic design of full crowns is further explored.

BACKGROUND: Radiation (IR)-induced DNA damage triggers cell cycle arrest and has a suppressive effect on the tumor microenvironment (TME). Wee1, a cell cycle regulator, can eliminate G2/M arrest by phosphorylating cyclin-dependent kinase 1 (CDK1). Meanwhile, programed death-1/programed death ligand-1 (PD-1/PDL-1) blockade is closely related to TME. This study aims to investigate the effects and mechanisms of Wee1 inhibitor AZD1775 and anti-PD-1 antibody (anti-PD-1 Ab) on radiosensitization of hepatoma. METHODS: The anti-tumor activity of AZD1775 and IR was determined by 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide (MTT) assay on human and mouse hepatoma cells HepG2, Hepa1-6, and H22. The anti-hepatoma mechanism of AZD1775 and IR revealed by flow cytometry and Western blot in vitro . A hepatoma subcutaneous xenograft mice model was constructed on Balb/c mice, which were divided into control group, IR group, AZD1775 group, IR + AZD1775 group, IR + anti-PD-1 Ab group, and the IR + AZD1775 + anti-PD-1 Ab group. Cytotoxic CD8 + T cells in TME were analyzed by flow cytometry. RESULTS: Combining IR with AZD1775 synergistically reduced the viability of hepatoma cells in vitro . AZD1775 exhibited antitumor effects by decreasing CDK1 phosphorylation to reverse the IR-induced G2/M arrest and increasing IR-induced DNA damage. AZD1775 treatment also reduced the proportion of PD-1 + /CD8 + T cells in the spleen of hepatoma subcutaneous xenograft mice. Further studies revealed that AZD1775 and anti-PD-1 Ab could enhance the radiosensitivity of hepatoma by enhancing the levels of interferon γ (IFNγ) + or Ki67 + CD8 T cells and decreasing the levels of CD8 + Tregs cells in the tumor and spleen of the hepatoma mice model, indicating that the improvement of TME was manifested by increasing the cytotoxic factor IFNγ expression, enhancing CD8 + T cells proliferation, and weakening CD8 + T cells depletion. CONCLUSIONS This work suggests that AZD1775 and anti-PD-1 Ab synergistically sensitize hepatoma to radiotherapy by enhancing IR-induced DNA damage and improving cytotoxic CD8 + T cells in TME.
Humans ; Animals ; Mice ; Carcinoma, Hepatocellular/radiotherapy* ; Cell Cycle Proteins/metabolism* ; Protein-Tyrosine Kinases/genetics* ; Apoptosis ; Programmed Cell Death 1 Receptor ; Cell Line, Tumor ; G2 Phase Cell Cycle Checkpoints ; Liver Neoplasms/radiotherapy* ; Tumor Microenvironment ; Pyrazoles ; Pyrimidinones

Background and purpose:Increased glucose metabolism is a characteristic of malignant tumors.This characteristic might be related to a facilitative glucose transporter(Glut-1) and the proliferating activities of tumors.This study was aimed to assess the relationship among the over-expression of facilitative glucose transporter(Glut-1) and proliferating cell nuclear antigen(PCNA) as well as the fluorine-18 fluorodeoxyglucose(18F-FDG) uptake of tumors in patients with nasopharyngeal carcinoma.Methods:Between March 2005 and August 2006,40 patients with nasopharyngeal carcinoma were imaged with 18F-FDG positron emission tomography(PET).Their maximum standard uptake values(SUVmax) were measured.The expression of Glut-1 and the proliferating cell nuclear antigen(PCNA) in the 40 cases were studied in paraffin sections by SP immunohistochemistry.Results:The 18F-FDG uptake of tumors of the 40 patients with nasopharyngeal carcinoma was 9.4?1.9(SUVmax).All 40 tumors tested Glut-1 positive and PCNA positive.The Glut-1 positive cells consisted of 45.18% of the tumor cell area,whereas the PCNA positive cells consisted of 36.18% of the tumor cell area.There were correlations between Glut-1 expression levels(r=0.369,P=0.019) and the tumors' 18F-FDG uptake but no correlations were found between PCNA expression level and the tumors' 18F-FDG uptake(r=0.135,P=0.407).Conclusion:Glut-1 over-expression correlates with 18F-FDG uptake whereas PCNA over-expression does not correlate with 18F-FDG uptake in patients with nasopharyngeal carcinoma.

Objective To study the relationship between the 18F-FDG PET/CT whole body imaging characteristics and pathologic features of small intestine primary malignant neoplasms.Methods A retrospective study was carried out on 18F-FDG PET/CT data of patients(n =44)with small intestine disease(25 malignant,19 benign).All results were proved by pathologiy,or diagnostic therapy and/or clinical follow-up.The intestinal wall thickness(IWT)and maxium standardized uptake value(SUVmax)were used to analyze the imaging features under different pathological conditions.Results(1)The incidence rate of local tumor formation for benign and malignant intestinal lesions was 31.6％ and 84.0％(x2 =10.40,P ＜ 0.01),respectively.The IWT was(0.75 ± 0.32)cm and(1.42 ± 0.20)cm(t =2.66,P ＜ 0.01),respectively.The S UVmax was(5.17 ± 3.04)and(9.65 ± 5.48)(t =2.88,P ＜ 0.01),respectively.The incidence rate of enlargement of mesenteric lymph nodes for benign and malignant intestinal lesions was 52.6％ and 72.0％(x2 =1.01,P ＞ 0.05),respectively.The SUVmax was(4.80 ± 1.91)and(7.00 ± 5.61)(t =1.11,P ＞ 0.05),respectively.(2)The metastasis incidence rate of other organs for intestinal malignant lesions was 44.0％.The most common metastasis organs were liver(28.0％),distant lymph nodes(20.0％)and bone (16.0％).The most pathological type of intestinal malignant lesions were malignant lymphoma(44.0％),adenocarcinoma(32.0％).The IWT was(1.41 ± 0.59)cm and(1.36 ± 0.62)cm(t =0.18,P ＞ 0.05),respectively.The SUVmax was(12.49 ± 7.00)and(7.93 ± 2.82)(t =7.55,P ＜ 0.01),respectively.The metastasis incidence rate was 9.1％ and 62.5 ％(x2 =3.89,P ＜ 0.05),respectively.(3)Taking the intestinal local tumor formation and SUVmax andnot less than 4.2 0 wall thickening,and / or metastasis as the main basis of the intestinal malignant lesions,the sensitivity,specificity and accuracy were 96.0％,94.7％ and 95.4％,respectively.The main pathological type of false positive for '8F-FDG PET/CT imaging was intestinal tuberculosis,and false negative was signet(f)ing cell carcinoma.Conclusion 18F-FDG PET/CT imaging has a higher clinical diagnosis value in differentiating small intestine primary malignant carcinoma from benign ones.The size and SUVmax of perifocus lymph nodes could not point out its malignant degree.The 18F-FDG uptake of the lesions is correlated with pathological type.The IWT is not correlated with pathological type.

Objective To evaluate the value of whole body 18F-FDG PET/CT in detecting small intestine adenocarcinoma (SIA).Methods A retrospective study of 18F-FDG PET/CT was performed on 29 cases (male 17,female 12) of SIA,21 cases of small intestine lymphoma (SIL) (male 15,female 6) and 10 cases of small intestine tuberculosis (SIT) (male 4,female 6).Visual and semi-quantitative methods (SUVmax) were used to summarize and analyse the 18F-FDG PET/CT resutls.One-way analysis of variance and x2 test were used to analyze the data.Results (1) 18F-FDG PET/CT for SIA showed a partially conglomerate pattern of hypermetabolic small bowel masses with nodular configurations.A typical SIL showed a partially annular abnormal growth with aggregated foci of radioactivity.SIT lesions were usually in form of stripes and/or nodules with high metabolic foci or lesions withskipped distribution.The SUVmax of SIA (8.44±3.82) was significantly lower than that of SIL (11.54±4.02; F=86.96,t=2.77,both P＜0.01),but not significantly different when compared with SIT (8.61±2.99; t=0.11,P＞0.05).(2) The incidence rates of peri-lesion lymph node enlargement in SIA,SIL and SIT were 72.41％ (21/29),85.71％ (18/21) and 70.00％ (7/10),respectively (x2 =1.50,P＞0.05).The SUVmax of peri-lesion lymph nodes in SIA (5.59±2.86) was significantly lower than that of SIL (11.10±5.72; F=56.56,t=3.85,both P＜0.01),but was not significantly different when compared with SIT (5.63± 3.36; t =0.30,P＞ 0.05).The detection rate of PET/CT on pefi-lesion lymph node enlargement of SIA was higher than CT (41.38％,12/29; x2 =5.69,P＜0.05).(3) The incidence rate of extra-intestinal metastases was 55.17％ (16/29) in SIA,and the most common metastatic sites were liver,bone and adrenal gland.The incidence rate of extra-intestinal lesions was 66.67％ (14/21) in SIL,most commonly presented as widespread multifocal nodal permeation.Extra abdominal tuberculous loci were found in 80.00％ (8/10) of SIT.The incidence rates of extra-intestinal involvement were not significantly different among SIA,SIL and SIT (x2=2.13,P＞0.05).(4) Among the 29 SIA cases,15 (51.72％) involved the ileum,8 (27.59％) jejunum,4 (13.79％) both jejunum and ileum,and 2 (6.90％) both jejunum and duodenum (x2 =18.16,P＜0.01).(5) Among the 29 SIA cases,primary SIA was found in 8 cases (27.59％),double primary in 7 cases (24.14％) and metastatic SIA in 14 eases (48.28％).(6) Based on the clinical data,pathological results and clinical follow-up,the diagnosis of SIA by 18F-FDG PET/CT had a sensitivity and specificity of 93.10％ (27/29) and 80.00％ (8/10),respectively.Conclusions 18F-FDG PET/CT is useful for the differential diagnosis of S1A and for supporting the diagnosis of single primary,multi-primary and metastatic SIA.

Abnormalities, Multiple ; Child, Preschool ; Facial Paralysis ; etiology ; Female ; Humans

Clostridioides difficile/genetics* ; Clostridioides ; Real-Time Polymerase Chain Reaction ; Feces ; Bacterial Proteins/genetics*