ABSTRACT
SPECT-CT integrates CT with SPECT, and can use 18F-fluorodeoxyglucose(FDG) for coincidence imaging. Its imaging can simultaneously indicate the function metabolism information from SPECT and the diagnostic information about anatomy from CT. And the target to no-target(T/NT) ratio can be calculated by using relative semi-quantitative analysis after once imaging. So SPECT-CT is one of the important imaging methods of tumor diagnosis and treatment. However, there is no accepted standard about cut-off level of T/NT ratio in the diagnosis for tumor, also about the selection location of region of interest (ROI) when you calculated the T/NT ratio. If T/NT ratio≥ 2.5 was referred as threshold in the diagnose of malignant tumor, there may be some false positive and false negative. This paper reviews the methods of the selection location of ROI for T/NT ratio in coincidence-CT imaging, and its influence factors, and its value of the diagnosis for benign malignancy, as well as its application progress in tumor diagnosis and treatment. It proves that the increased value by CT to the pure SPECT imaging is that it can more accurately detect lesions anatomically. By the way, it provide more accurate positioning information for the rang of ROI. Thereby, it provide more useful imaging information for clinical biopsy, surgery or the rang of radiotherapy target area.
ABSTRACT
<p><b>BACKGROUND</b>Fluorine-18-fluorodeoxyglucose ((18)F-FDG) positron emission tomography imaging can be used to assess the treatment efficacy of chemotherapy and prognosis. The aim of this study was to determine the uptake rate of (18)F-FDG in colon cancer HCT-116 cells, and to evaluate the treatment efficacy of chemotherapy, hyperthermia and thermo-chemotherapy through the uptake inhibition rate of (18)F-FDG.</p><p><b>METHODS</b>The uptake rate of (18)F-FDG in HCT-116 cells was determined at various experimental conditions. The inhibition rate of cell growth, uptake rate of (18)F-FDG and uptake inhibition rate of (18)F-FDG in HCT-116 cells treated with 5-fluorouracil (5-FU) at various concentrations were determined. In HCT-116 cells subjected to chemotherapy (5-FU, 100 µg/ml), hyperthermia (43°C, 40 minutes) and thermo-chemotherapy for 24 hours, the inhibition rate of cell growth and uptake inhibition rate of (18)F-FDG were determined; early apoptosis, the morphology and ultrastructure of HCT-116 cells were examined; and the contents of glucose and lactate dehydrogenase (LDH) in the cell culture medium of HCT-116 cells were determined. One-way analysis of variance (ANOVA) and correlation analyses were conducted by using SPSS 16.0 software.</p><p><b>RESULTS</b>The uptake rate of (18)F-FDG in HCT-116 cells was (44.25 ± 2.19)%. Under the condition of adding 5-FU at various concentrations for 24 hours, the uptake rate of (18)F-FDG was negatively correlated with 5-FU dosage (r = -0.879, P < 0.01); the inhibition rate of cell growth revealed a positive correlation with the uptake inhibition rate of (18)F-FDG (r = 0.831, P < 0.01). In HCT-116 cells subjected to hyperthermia, chemotherapy, and thermo-chemotherapy for 24 hours, the uptake inhibition rates of (18)F-FDG were (12.94 ± 2.80)%, (28.25 ± 4.59)%, and (21.60 ± 3.68)%, respectively. The early apoptotic rates of HCT-116 cells were (9.80 ± 0.16)%, (19.80 ± 2.40)%, and (15.70 ± 1.80)%, respectively. Moreover, the contents of glucose and LDH in cell culture medium of HCT-116 cells after treatments were higher than those before treatment.</p><p><b>CONCLUSION</b>The uptake inhibition rate of (18)F-FDG can be used for early evaluation of hyperthermia and 5-FU treatment efficacy on cancer cells although hyperthermia (43°C, 40 minutes) does not reveal the synergistic effect on 5-FU at the low dosage.</p>
Subject(s)
Humans , Apoptosis , Cell Proliferation , Colonic Neoplasms , Metabolism , Fever , Metabolism , Fluorodeoxyglucose F18 , Metabolism , Fluorouracil , Pharmacology , HCT116 Cells , Microscopy, Electron, TransmissionABSTRACT
Objective To evaluate the usefulness of 18F-FLT PET/CT imaging in detecting and staging nasopharyngeal carcinoma (NPC) patients.Methods Thirteen patients with NPC underwent wholebody 18F-FLT PET/CT imaging,one of which underwent whole-body 18F-FDG PET/CT imaging one day earlier.SUVmax and SUVmean from 18F-FLT and18F-FDG imaging were obtained using circular ROI in primary and metastasis lesions and were compared with the results of histopathology.The staging results by 18 F-FLT PET was compared with those by CT.Results The SUVmax and SUVmean obtained from 18F-FLT imaging in 22nasopharyngeal sites in 13 patients were 6.04 ±3.61 and 5.09 ±2.89,and the SUVmax and SUVmean in 26 lymphadenopathy were 5.56 ± 3.11 and 4.65 ± 2.79.18 F-FDG SUVmax were higher than 18 F-FLT SUVmax in one primary lesion ( 8.32 vs 4.38 ) and two lymph nodes (3.30 ± 0.07 vs 1.48 ± 0.06) in the patient who underwent the two imagings.Compared with CT staging results,the TNM stage in 3 patients had been changed based on 18 F-FLT PET/CT imaging.Conclusions High radioactivity of primary and second lesions can be detected on 18F-FLT imaging in patients with NPC and 18F-FLT PET/CT imaging may be useful in staging for NPC.
ABSTRACT
Objective To investigate the depressing effect of antigene peptide nucleic acid (AGPNA)on the k-ras gene expression of human pancreatic cancer Patu8988 cells, the inducing apoptosis effect on Patu8988 cells, and the biodistribution characteristics in nude mice bearing xenografts using 188Re-k-ras-AGPNA.Methods The expression level of k-ras mRNA and the expression ratio of k-ras protein in Patu8988 cells transfected with AGPNA was measured by RT-PCR and flow cytometry ,respectively. The degree of cellular apoptosis 3 to 5 d after treating Patu8988 cells with 188Re-k-ras-AGPNA or 188ReO4- was determined by flow cytometry. For biodistribution study, 58 nude mice bearing Patu8988 cell xenografts were divided into two groups: intratumoral injection of 188Re-k-ras-AGPNA (Group A) and 188ReO4- (Group B). At different time points, the mice were sacrificed and organs of interest were excised, weighted and counted by a gamma counter. The organ uptake was calculated as a % ID/g and the absorbed doses of organs were calculated. One-way analysis of variance was used. Results After transfected with 1 nmol/ml AGPNA, the k-ras mRNA gray scale ratio and the expression ratio of k-ras protein were 1.00 ± 0.39 and (15.05 ± 5.07)%, respectively. They were significantly lower than those of the control group with 1.86 ± 0.07 and (24. 38 ± 5.40) % (F = 2. 545, 5. 327, P<0. 05). At 4 and 5 d after treatment in Group A, float cells' apoptosis ratios were (26.30 ± 7.45) % and (27.90 ± 10. 38) %, respectively. Tumors were the major distribution site in Group A with uptake of (37.47 ±21.31), (35.96 ±7.80) and (15.46 ±4.93) %lD/g at 1 h, 1 d and 7 d after intra-tumor injection, respectively. The absorbed dose of tumor was 15 569 mGy/MBq. Condusions Transfection with k-ras-AGPNA on Patu8988 cells may inhibit k-ras expression at mRNA and protein expression level, and 188Re-k-ras-AGPNA can induce apoptosis of Patu8988 cells.Tumor is the major distribution site in nude mice bearing human pancreatic cancer xenografts after intratumoral injection of 188Re-k-ras-AGPNA.