RESUMO
PURPOSE: Dopamine transporters (DAT) modulate pre-synaptic dopamine and physiological functions such as movement and reward. DAT also mirrors disease state in neurological disorders, rendering it an essential diagnostic target. [18F]PR04.MZ is a new PET imaging agent for DAT with an improved affinity and selectivity profile, for which we here describe the complete pharmacokinetic evaluation in healthy controls. METHODS: Thirty-two healthy subjects underwent T1-weighted MRI and dynamic PET scans for 180 min with arterial blood sampling (n = 5) or 90 min without blood sampling (n = 25) after injection of 197.6 ± 12.2 MBq [18F]PR04.MZ. Blood and plasma metabolite analysis were performed. MRI-based normalization of brain images, delineation of VOIs, and kinetic modeling was conducted to determine distribution volumes (Vt) and binding potentials (BPnd). The impact of scan duration was evaluated and repeated PET scans were performed to assess test-retest variability (n = 5). A static imaging protocol has been validated for clinical applications. RESULTS: [18F]PR04.MZ showed rapid metabolization in circulation, very high uptake in striatum and midbrain, and very low non-specific binding. The two-tissue compartment model 2TCM provided best fits for measured time-activity-curves and calculated Vts in putamen, caudate, substantia nigra pars compacta (SNpc), and cerebellar cortex were 11.83, 9.73, 2.12, and 0.57, respectively. All non-invasive models correlated well with BPnd values derived from 2TCM but underestimated DAT availability by about 28-33%. Of those, simplified reference tissue model (SRTM) provided the best fits, lowest Akaike Information Criteria values, and BPnd values of 14.82, 11.95, and 2.63 in putamen, caudate, and SNpc, respectively. BPnd estimates for striatal regions and SNpc were stable between 90 and 130 min post-injection. Test-retest results were excellent, showing low variability in all and excellent reliability in most relevant regions. Static imaging from 60 to 90-min post-injection is a viable alternative for quantification. CONCLUSIONS: [18F]PR04.MZ is a PET tracer with very high affinity, selectivity, and specific uptake in striatum and midbrain. 2TCM and SRTM provide good fits, high and stable Vts or BPnds, and good test-retest reliability for precise quantification of DAT in human subjects.
Assuntos
Dopamina , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Humanos , Tomografia por Emissão de Pósitrons , Reprodutibilidade dos TestesRESUMO
Propósito. Los TNE avanzados tienen escasa respuesta a radioterapia o quimioterapia, el tratamiento sistémico con análogos de la SST radiactivos es una herramienta promisoria en su tratamiento. Presentamos nuestra experiencia, pionera en Latinoamérica, utilizando análogos de SST marcados con 90Y ó 177Lu. Material. Evaluamos 40 pacientes (50.3 años, rango 12-74) con TNE confirmados histológicamente y sobre-expresión de receptores de SST demostrada mediante imágenes. SPECT (111In-DOTATOC) ó PET/CT (68Ga-DOTATATE). Se evaluó respuesta clínica, laboratorio, imágenes con 111In-DOTATATE, post-terapia con 90Y ó 177Lu, 68Ga-DOTATATE PET/CT o TAC. Resultados. Observamos progresión de enfermedad en 10 (25.0 por ciento), remisión parcial en 25 (62.5 por ciento), enfermedad estable en 3 (7.5 por ciento) y remisión completa en 2 (5.0 por ciento). Hubo escasa toxicidad sin deterioro renal significativo. Observamos reducción tumoral y mejoría de calidad de vida en la mayoría de los pacientes. Conclusión. La terapia con radiopéptidos es un procedimento seguro y efectivo en el tratamiento de TNE avanzados.
Purpose. Advanced NETs have little response to radiotherapy or chemotherapy, systemic treatment with radioactive SST analogous is a promissory tool in its treatment. We present our pioneering experience in Latin America using analogous of SST labeled either with 90Y or 177Lu. Materials. We evaluated 40 patients (50.3 years, range 12-74) with histological proved NET and SST receptors over-expression demonstrated by SPECT or PET/CT images with 111In-DOTATOC or 68Ga-DOTATATE. We evaluated clinical response, laboratory test, images with 111In-DOTATATE, 90Y, 177Lu, and 68Ga-DOTATATE PET/CT or CT. Results. We observed progression of disease in 10 (7,5 percent), partial remission in 25 (62,5 percent), stable disease in 3 (7,5 percent) and complete remission in 2 (5,0 percent). There was little toxicity without significant renal deterioration. We observed tumor mass reduction and improvement of quality of life in most of the patients. Conclusion. The therapy with radiopeptides is a safe and effective procedure in the treatment of advanced NET.
Assuntos
Humanos , Masculino , Adolescente , Adulto , Feminino , Pessoa de Meia-Idade , Compostos Organometálicos/uso terapêutico , Compostos Radiofarmacêuticos/uso terapêutico , Somatostatina/análogos & derivados , Tumores Neuroendócrinos/radioterapia , Indução de Remissão , Lutécio/uso terapêutico , Octreotida/análogos & derivados , Octreotida/uso terapêutico , Radioisótopos de Ítrio/uso terapêutico , Resultado do TratamentoRESUMO
We report a 74-year-old male with liver metastases from a neuroendocrine tumor (NET) of unknown origin. Conventional imaging studies with ultrasound, computed tomography colonoscopy and Positron emission tomography-computed tomography (PET/CT) with 18Fluor odeoxyglucose did not identify the site of origin of the primary tumor. The patient was submitted for a PET/CT scan with a new radiopharmaceuticai, the somatostatin analogue 68Ga-DOTATATE. This new technique demonstrated increased focal uptake at the ileocecal valve. This lesion and other two liver metastases were surgically removed. The histopathology and immunohistochemistry analysis confirmed the diagnosis of NET (carcinoid). This case illustrates the advantages of the PET/CT scan with 68Ga-DOTATATE.
Assuntos
Neoplasias do Íleo , Valva Ileocecal , Tumores Neuroendócrinos , Compostos Organometálicos , Idoso , Humanos , Neoplasias do Íleo/diagnóstico por imagem , Valva Ileocecal/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Neoplasias Hepáticas/secundário , Masculino , Tumores Neuroendócrinos/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodosRESUMO
Fibrolamellar hepatocellular carcinoma (FLC) is a rare histologic variant of hepatocellular carcinoma that appears most commonly in teenagers and young adults. The diagnosis is often made incidentally and surgical resection is the only curative treatment. Here we report two cases of incidental FLC involving a 19 year-old male, initially diagnosed with screening abdominal ultrasound, and a 14 year-old female that presented with abdominal pain. Diagnostic workup consisted of abdominal PET/CT and MR1 Imaging studies and tissue diagnosis was confirmed with percutaneous liver biopsy. Both patients were treated with radical liver resection/tumor excision. However, tumor recurrence was observed in both during short-term follow-up. The male patient was treated successfully with surgical treatment however the female patient succumbed top regression of disease.
Assuntos
Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/cirurgia , Adolescente , Biópsia , Carcinoma Hepatocelular/patologia , Evolução Fatal , Feminino , Hiperplasia Nodular Focal do Fígado/patologia , Hiperplasia Nodular Focal do Fígado/cirurgia , Humanos , Neoplasias Hepáticas/patologia , Linfonodos/patologia , Masculino , Recidiva Local de Neoplasia , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
We report a 74-year-old maie with liver metastases from a neuroendocrine tumor (NET) of unknown origin. Conventionai imaging studies with ultrasound, computed tomography coionoscopy and Positron emission tomography-computed tomography (PET/CT) with 18Flúor odeoxyglucose did not identify the site of orígin of the primary tumor. The patient was submitted for a PET/CT sean with a new radiopharmaceuticai, the somatostatin anaiogue 68Ga-DOTATATE. This new technique demostrated increased focal uptake at the ileocecal valve. This lesión and other two liver metastases were surgically removed. The histopathology and immunohistochemistry analysis confirmed the diagnosis of NET (carcinoid). This case illustrates the advantages of the PET/CT sean with 68Ga-DOTATATE.
Assuntos
Idoso , Humanos , Masculino , Neoplasias do Íleo , Valva Ileocecal , Tumores Neuroendócrinos , Compostos Organometálicos , Neoplasias do Íleo , Neoplasias do Íleo , Valva Ileocecal , Valva Ileocecal , Neoplasias Hepáticas , Neoplasias Hepáticas , Neoplasias Hepáticas/secundário , Tumores Neuroendócrinos , Tumores Neuroendócrinos , Tomografia por Emissão de Pósitrons/métodos , Tomografia Computadorizada por Raios X/métodosRESUMO
Fibrolamellar hepatocellular carcinoma (FLC) is a rare histologic variant of hepatocellular carcinoma that appears most commonly in teenagers and young adults. The diagnosis is often made incidentally and surgical resection is the only curative treatment. Here we report two cases of incidental FLC involving a 19 year-old male, initially diagnosed with screening abdominal ultrasound, and a 14 year-old female that presented with abdominal pain. Diagnostic workup consisted of abdominal PET/CT and MRI Imaging studies and tissue diagnosis was confirmed with percutaneous liver biopsy. Both patients were treated with radical liver resection/tumor excision. However, tumor recurrence was observed in both during short-term follow-up. The male patient was treated successfully with surgical treatment however the female patient succumbed top regression of disease.
Assuntos
Adolescente , Feminino , Humanos , Masculino , Adulto Jovem , Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/cirurgia , Biópsia , Carcinoma Hepatocelular/patologia , Evolução Fatal , Hiperplasia Nodular Focal do Fígado/patologia , Hiperplasia Nodular Focal do Fígado/cirurgia , Neoplasias Hepáticas/patologia , Linfonodos/patologia , Recidiva Local de Neoplasia , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
INTRODUCTION: After a cholecystectomy, incidental gallbladder cancer (IGC) requires accurate imaging studies to determine the actual extent of the disease to properly tailor subsequent treatment. The aim of this study was to evaluate the utility of (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)FDG PET-CT) to provide optimal pre-treatment staging in patients with IGC. MATERIAL AND METHODS: Between January 2006 and August 2008, all patients with IGC and at least muscular layer invasion were studied with (18)FDG PET-CT. The examination was considered positive when the standardized uptake values (SUV) were >/=2.5. In all instances patients were offered to undergo definitive exploration and possible radical resection. RESULTS: The series included 32 patients, 26 women and 6 men, with a median age of 57 years (range 30-81 years). The examination was performed at a median time of 6 weeks after cholecystectomy (range 2-52 weeks). (18)FDG PET-CT was negative in 13 patients and positive in 19 patients: 9 with localized potentially resectable disease (PRD) and in 10 with disseminated disease. Of the 13 patients with negative PET-CT, 9 refused surgery and 4 underwent formal exploration: 3 patients were resected with no disease identified in the final pathology report (FPR) and 1 was not resected as a result of peritoneal carcinomatosis. Of the 9 with PRD, 4 patients refused reoperation and 5 underwent exploration: 3 were resected with residual disease noted in the FPR and 2 did not undergo resection because of dissemination. Two patients with disseminated disease were reoperated and in both instances disseminated disease was confirmed. The median survival for the entire group was 20.3 months (range 1.6-32.9 months). The median survival for those patients with negative PET-CT was 13.5 months (range 5.6-32.9 months), 6.2 months (range 1.6-18.7 months) for localized potentially resectable disease and 4.9 months (range 2-14.1 months) for disseminated disease (P < 0.003). CONCLUSIONS: For patients presenting with stage T1b or greater IGC, the use of (18)FDG PET-CT will help reduce the number of patients undergoing non-therapeutic re-exploration and may help to determine the likely prognosis. (18)FDG PET-CT might be a useful tool for the selection of patients for potentially curative treatment.
RESUMO
BACKGROUND: Gallbladder cancer is an aggressive malignancy and radical resection is the only curative therapy available. Metastatic disease in the thyroid is rarely seen; however, different studies have confirmed that the most common primary tumor source is the kidney. CASE REPORT: Thyroid metastases from tumors originating in the gastrointestinal tract have been reported. We report a patient with gallbladder cancer (T2N1M0) treated with radical resection and postoperative chemoradiation who developed thyroid metastases.