RESUMO
INTRODUCTION: AMBA is a bombesin analogue that binds to GRPr. In a mouse model of estrogen-dependent human breast cancer, we tested whether (68)Ga-AMBA can be used for PET detection of GRPr-expressing tumors and could be more accurate than (18)F-FDG to monitor tumor response to hormone therapy. METHODS: The radiolabeling of (68)Ga-AMBA was automated using a R&D Synchrom module. ZR75-1, a breast cancer cell line, was xenografted in nude mice. (68)Ga-AMBA tumor uptake was compared with that of (18)F-FDG before and after treatment with tamoxifen. RESULTS: AMBA was (68)Ga-radiolabelled in 30min with 95.3% yield and purity≥98%. Prior to treatment, (68)Ga-AMBA was highly concentrated into tumors (tumor to non-tumor ratio=2.4 vs. 1.3 with (18)F-FDG). With tamoxifen treatment (n=6) (68)Ga-AMBA uptake plateaued after 1week and decreased after 2weeks, with a significant reduction compared to controls (n=4). In contrast the effect of tamoxifen treatment could not be appreciated using (18)F-FDG. CONCLUSIONS: (68)Ga-AMBA appeared better than (18)F-FDG to visualize and monitor the response to hormone treatment in this breast cancer model.
Assuntos
Neoplasias da Mama/diagnóstico por imagem , Fluordesoxiglucose F18/metabolismo , Oligopeptídeos/metabolismo , Tomografia por Emissão de Pósitrons , Tamoxifeno/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica , Feminino , Fluordesoxiglucose F18/farmacocinética , Radioisótopos de Gálio , Humanos , Camundongos , Oligopeptídeos/farmacocinética , Carga Tumoral/efeitos dos fármacosAssuntos
Linfangiogênese , Melanoma/patologia , Complicações Neoplásicas na Gravidez/patologia , Prolactina/metabolismo , Neoplasias Cutâneas/patologia , Adulto , Biópsia por Agulha , Estudos de Casos e Controles , Feminino , Humanos , Imuno-Histoquímica , Melanoma/genética , Melanoma/fisiopatologia , Gravidez , Complicações Neoplásicas na Gravidez/genética , Complicações Neoplásicas na Gravidez/fisiopatologia , Prolactina/genética , Estudos Prospectivos , Valores de Referência , Transdução de Sinais , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/fisiopatologiaRESUMO
UNLABELLED: PET with fluoroethylthyrosine (FET), amino-acid analogue, has been performed in Germany since the beginning of the decade for molecular and metabolic imaging of brain tumours, since FDG, the glucose analogue which is the reference tracer for clinical PET, has this drawback to be taken-up intensely by cerebral cortex. We report on our preliminary results on the comparison of PET/CT with FET and FDG in 10 evaluable patients presenting with a brain lesion either at diagnosis or after treatment. In an attempt to optimise specificity, FET PET/CT has been acquired as a static image 1h after injection, while the most current practice is a dynamic 40 min acquisition starting at FET injection. With our acquisition protocol, diagnostic performance of FET was 88% sensitivity and 80% accuracy vs 13% and 30% respectively for FDG. CONCLUSION: FET is a radiopharmaceutical with clinical usefulness for the diagnosis, delineation and monitoring of brain tumours. Association with FDG allows identification of high-grade lesions or components, but it could be avoided providing that acquisition and quantification procedures of FET PET/CT would have been better optimised and standardised.