Gene expression is closely related to cell survival, cell-to-cell adhesion or cell spreading; therefore, HCCs with high 18F-FDG uptake appear to have more aggressive biological properties than those with low uptake.

Multimodal nanoparticles have been extensively studied for target-specific imaging and therapy of various diseases, including cancer. In this study, radiolabeled arginine-glycine-aspartic acid (RGD)-functionalized Er 31 /Yb 31 co-doped NaGdF 4 upconversion nanophosphors (UCNPs) were synthesized and evaluated as a multimodal PET/MR/optical probe with tumor angiogenesisspecific targeting properties. Methods: A dimeric cyclic RGDyk ((cRGDyk) 2 ) peptide was conjugated to polyacrylic acid-coated NaGdF 4 :Yb 31 /Er 31 UCNPs along with polyethylene glycol molecules and was consecutively radiolabeled with 124 I. In vitro cytotoxicity testing was performed for 3 d. Upconversion luminescence imaging of (cRGDyk) 2 -UCNP was performed on U87MG cells with a laboratory-made confocal microscope. In vivo small-animal PET and clinical 3-T T1-weighted MR imaging of 124 I-labeled RGD-functionalized UCNPs was acquired with or without blocking of cyclic RGD peptide in a U87MG tumor model. Inductively coupled plasma mass spectrometry and biologic transmission electron microscopy were done to evaluate gadolinium concentration and UCNP localization, respectively. Results: Polymer-coated UCNPs and dimeric RGD-conjugated UCNPs were monodispersely synthesized, and those of hydrodynamic size were 30 6 8 nm and 32 6 9 nm, respectively. (cRGDyk) 2 -UCNPs have a low cytotoxic effect on cells. Upconversion luminescence signals of (cRGDyk) 2 -UCNP were specifically localized on the surface of U87MG cells. 124 I-c(RGDyk) 2 -UCNPs specifically accumulated in U87MG tumors (2.8 6 0.8 vs. 1.3 6 0.4 percentage injected dose per gram in the blocking experiment), and T1-weighted MR images showed significant positive contrast enhancement in U87MG tumors. Tumor localization of 124 I-c(RGDyk) 2 -UCNPs was confirmed by inductively coupled plasma mass spectrometry and biologic transmission electron microscopy analysis. Conclusion: These results suggest that 124 Ilabeled RGD-functionalized UCNPs have high specificity for a v b 3 integrin-expressing U87MG tumor cells and xenografted tumor models. Multimodal UCNPs can be used as a platform nanoparticle with multimodal imaging for cancer-specific diagnoses.

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We evaluated the potential of 18 F-FDG PET/CT and diffusionweighted imaging (DWI) to monitor the histologic response in patients with extremity osteosarcoma receiving neoadjuvant chemotherapy, using sequential PET/CT and MR imaging. Methods: We prospectively registered 28 patients with high-grade osteosarcoma treated with 2 cycles of neoadjuvant chemotherapy and surgery. All patients underwent sequential 18 F-FDG PET/CT and MR imaging before (PET/MR1) and after neoadjuvant chemotherapy (PET/MR2). Maximum standardized uptake value (SUV), tumor volume based on MR imaging (MRV), and the mean apparent diffusion coefficient (ADC) values were measured on PET/MR1 (SUV1, MRV1, and ADC1) and PET/MR2 (SUV2, MRV2, and ADC2). The percentage changes in maximum SUV (ΔSUV), MRV (ΔMRV), and ADC (ΔADC) were calculated, and the correlations among these parameters were evaluated. After surgery, the effects of neoadjuvant chemotherapy were graded histopathologically: grades III and IV (necrosis of $ 90%) indicated a good response, and grades I and II (necrosis of , 90%) indicated a poor response. The optimum cutoff values of ΔSUV, ΔMRV, ΔADC, and their combination for predicting histologic response were assessed by single-and multi-receiver-operating-characteristic curve analysis. Results: Twenty-seven patients were enrolled in the present study after 1 patient with inadequate acquisition of MR imaging was excluded. ΔSUV and ΔADC negatively correlated with each other (r 5 20.593, P 5 0.001), and ΔMRV did not correlate with ΔSUV or ΔADC. The cutoff value, sensitivity, specificity, and accuracy for predicting good histologic response were # 252%, 67%, 87%, and 78%, respectively, for ΔSUV and . 13%, 83%, 73%, and 78%, respectively, for ΔADC. However, ΔMRV did not predict histologic response. Sensitivity, specificity, and accuracy were 83%, 87%, and 85%, respectively, using the combined criterion of ΔSUV # 231% and ΔADC . 13%. Conclusion: In the current preliminary study, both PET/CT and DWI are useful for predicting histologic response after neoadjuvant chemotherapy in osteosarcoma. Combining PET/CT and DWI may be an effective method to predict the histologic response of patients to neoadjuvant chemotherapy.

A higher SUVmax on pretreatment F-FDG PET/CT can predict poorer survival in patients with gastric lymphoma.

Immuno-PET provides valuable information about tumor location, phenotype, susceptibility to therapy, and treatment response, especially to targeted radioimmunotherapy. In this study, we prepared antiepidermal growth factor receptor (EGFR) antibody via identical chelator, 3,6,9,15-tetraazabicyclo[9.3.1]-pentadeca-1(15),11,13-trience-3,6,9,-triacetic acid (PCTA), labeled with 64 Cu or 177 Lu to evaluate the EGFR expression levels using immuno-PET and the feasibility of radioimmunotherapy in an esophageal squamous cell carcinoma (ESCC) model. Methods: Cetuximab was conjugated with p-SCN-Bn-PCTA and radiolabeled with 64 Cu or 177 Lu. In vitro EGFR expression levels were determined and compared using flow cytometry and cell binding assay. In vivo EGFR expression levels were evaluated via immuno-PET imaging of 64 Cu-cetuximab and biodistribution analysis. Micro-SPECT/CT imaging, biodistribution, and radioimmunotherapy studies of 177 Lu-cetuximab were performed in the ESCC model. Therapeutic responses were monitored using 18 F-FDG PET and immunohistochemical staining. Results: 64 Cu-or 177 Lu-labeled antibodies showed high radiolabeling yield (.98%), stability (.90%), and favorable immunoreactivity. In vitro EGFR status measured by cell binding assay was correlated with the flow cytometry data. Immuno-PET, micro-SPECT/CT, and biodistribution demonstrated specific uptake in ESCC tumors depending on the EGFR expression levels. Tumor accumulation of 64 Cu-and 177 Lu-cetuximab was peaked at 48 and 120 h, respectively. Radioimmunotherapy with 177 Lu-cetuximab showed significant inhibition of tumor growth (P , 0.01) and marked reduction of 18 F-FDG SUV compared with that of control (P , 0.05). Terminal deoxynucleotidyl transferase dUTP nick-end labeling positivity and Ki-67 staining indices increased and decreased, respectively, in the radioimmunotherapy group compared with other groups (P , 0.01). Conclusion: 64 Cu-cetuximab immuno-PET represented EGFR expression levels in ESCC tumors, and 177 Lu-cetuximab radioimmunotherapy effectively inhibited the tumor growth. The diagnostic and therapeutic convergence radiopharmaceutical 64 Cu-/ 177 Lu-PCTA-cetuximab may be useful as a diagnostic tool in patient selection and a potent radioimmunotherapy agent in EGFR-positive ESCC tumors.

Human amniotic epithelial cells (h-AECs), which have various merits as a cell source for cell therapy, are known to differentiate into cardiomyocytes in vitro. However, the ability of h-AECs to differentiate into cardiomyocytes in vivo and their cell transplantation effects on myocardial infarction are still unknown. In this study, we assessed whether h-AECs could differentiate into cardiomyocytes in vivo and whether h-AECs transplantation can decrease infarct size and improve cardiac function, in comparison to transplantation of cord bloodderived mesenchymal stem cells (MSCs) or adipose tissue-derived MSCs. For our study, we injected h-AECs, cord blood-derived MSCs, adipose tissue-derived MSCs, and saline into areas of myocardial infarction in athymic nude rats. After 4 weeks, 3% of the surviving h-AECs expressed myosin heavy chain, a marker specific to the myocardium. Compared with the saline group, all cell-implanted groups showed a higher ejection fraction, lower infarct area by positron emission tomography and histology, and more abundant myocardial gene and protein expression in the infarct area. We showed that h-AECs can differentiate into cardiomyocyte-like cells, decrease infarct size, and improve cardiac function in vivo. The beneficial effects of h-AECs were comparable to those of cord blood and adipose tissue-derived MSCs. These results support the need for further studies of h-AECs as a cell source for myocardial regeneration due to their plentiful availability, low immunity, and lack of ethical issues related to their use.

PET/CT is more sensitive and accurate than BS for diagnosing bone metastases in osteosarcoma. The combined use of PET/CT and BS improves sensitivity.