Patricio González E

Utilidad clínica de la fusión SPECT/CT con marcadores externos en patología oncológica

Interpretation of abnormal foci with high traceruptake may require morphological correlation. Fusion of functional images obtained by singlephoton emission computed tomography (SPECT) and anatomical images obtained by computedtomography (CT) or magnetic resonance (RM) allows an integrated comprehension ofcomplementary information.

Valores normales de captación de 131Yodo de 2 y 24 horas

Background: Radiolabeled iodine uptake is a useful tool in the study of thyroid diseases. Aim: To obtain normal values for 131 Iodine thyroid uptake in healthy volunteers. Material and methods: A total of 105 subjects were included (52 males and 53 females), with a mean age of 45 years (range: 20 to 68, evenly distributed in decades). A questionnaire was applied and a clinical examination was performed to rule out endocrine diseases. Serum TSH and anti-thyroperoxidase antibodies were also measured. The oral 131I dose was 5-10 fiCi, and a Thyrad equipment was used for measurements at 2 and 24 h. Results: Mean global iodine uptake was 5.5%±1.8% (range: 2.3-12.0) at 2 h and 16.2±4.8% (range: 6.5-30.1) at 24 h. The values at 2 h among women and men were 6.0±1.8 and 4.9±1.6%, respectively, (p <0.02). At 24 h, the figures were 17.3±4.5 and 15.0±4.9%, respectively (p =0.01). Compared to their younger counterparts, radioactive iodine uptake was lower among volunteers older than 40 years, at 2 h (5.0±1.7 and 6.0±1.8, respectively, p <0.02) and at 24 h (14.9±4.4 and 17.6±4.9%, respectively, p <0.01). Conclusions: Normal thyroid uptake values in adults are influenced bygender and age. Normal thyroid iodine uptake values are slightly higher in females. Iodine thyroid uptake values decrease slightly in subjects aged more than 40years.

Uso de la tomografía de emisión de positrones PET con F18-FDG en la evaluación de lesiones pulmonares sospechosas de neoplasia

Positron-emission tomography (PET) with F18-fluorodeoxyglucose (FDG) is very helpful in the evaluation and management of lung lesions. It is specially useful for the characterization of solitary nodules, for the staging, evaluation of recurrence and therapeutic response in non-small cell lung cancer, for the evaluation of small cell lung cancer and for the assessment of pulmonary metastases. This article is a literature review on PET with FDG in lung cancer. A preliminary analysis of PET results at the Military Hospital in Santiago, Chile, is also presented

PET, TOMOGRAFIA POR EMISION DE POSITRONES: PRESENTACION DE UN CASO CLINICO

Se presenta un caso clinico de una paciente estudiada por nodulo pulmonar solitario con Tomografia por Emision de Positrones utilizando Fluor18-deoxiglucosa. Con el estudio metabolico quedo en evidencia la malignidad del nodulo y la aparicion de dos nuevos focos sugerentes de diseminacion, no demostrados por otras tecnicas diagnosticas

Rendimiento del Spect Talio201 reposo-redistribución para predecir viabilidad post infarto reciente del miocardio

Background: The detection of viability after acute myocardial infarction is primordial to select the most appropriate therapy, to decrease cardiac events and abnormal remodeling. Thallium201 SPECT is one of the radionuclide techniques used to detect viability. Aim: To evaluate the use of Thallium201 rest-redistribution SPECT to detect myocardial viability in reperfused patients after a recent myocardial infarction. Patients and methods: Forty one patients with up to of 24 days of evolution of a myocardial infarction were studied. All had angiographically demonstrated coronary artery disease and were subjected to a successful thrombolysis, angioplasty or bypass grafting. SPECT Thallium201 images were acquired at rest and after 4 h of redistribution. These results were compared with variations in wall motion score, studied at baseline and after 3 or 4 months with echocardiography. Results: The sensitivity of rest-redistribution Thallium201 SPECT, to predict recovery of wall motion was 91% when patient analysis was performed and 79% when segmental analysis was done in the culprit region. The figures for specificity were 56 and 73% respectively. Conclusions: Rest-distribution Thallium201 SPECT has an excellent sensitivity to predict myocardial viability in recent myocardial infarction. The data obtained in this study is similar to that reported for chronic coronary artery disease (Rev Med Chile 2002; 130: 243-50).

Utilidad de la tomografía de emisión de positrones en oncología pediátrica

El PET-FDG es una tecnica que evalua el metabolismo glucidico celular. Su mayor utilidad es en oncologia, ya que permite distinguir tumores malignos de benignos, seleccionar los sitios de biopsia, etapificar las neoplasias, determinar la respuesta a tratamiento y distinguir entre cicatriz y enfermedad residual post tratamiento. En ninos, las principales indicaciones son linfomas, tumores del sistema nervioso central, sarcomas de tejidos blandos, osteosarcoma y sarcoma de Ewing, neuroblastoma y nefroblastoma. Existen otros tumores menos comunes que tambien pueden ser evaluados eficazmente con FDG tales como: tumores de la vaina de nervios perifericos, hepatoblastomas, tumor de Wilms y cancer de tiroides. Hay pocas publicaciones en esta poblacion debido al pequeno numero de pacientes estudiados y la baja incidencia de cancer. Es importante considerar las variaciones en la distribucion normal del trazador respecto al adulto para optimizar la interpretacion de las imagenes. El objetivo de este articulo es efectuar una revision de las indicaciones del PET-FDG y presentar nuestra casuistica inicial en poblacion pediatrica

Utilidad de la deoxiglucosa marcada con flúor-18 (FDG) en el manejo de los linfomas

Positron emission tomography (PET) with fluorine-18 labeleddeoxyglucose (FDG) is useful in the management of lymphomas. In this review, some generalconcepts of this metabolic test are defined. It has an excellent diagnostic yield in Hodgkin disease aswell as in most non Hodgkin lymphomas. Staging, restaging residual mass evaluation and thecontrol of therapy are the main indications for FDG-PET. Images with FDG have a high diagnosticand prognostic value, that is superior to anatomical images and conventional staging techniques.They are also helpful for the assessment of tumor activity in abnormal lymph nodes or large massesthat have been treated and reduce their size slowly or show an incomplete resolution. Currently, theresolution of dedicated PET equipments is 6 mm and bigger lesions can easily be detected. The maindifferences and advantages of FDG versus gallium-67 in lymphoma are also discussed, as well as theinitial local experience with the technique in lymphoma patients (Rev Med Chile 2006; 134: 910-9).(

Artículo de revisión Aplicaciones clínicas del PET

Functional imaging using PET (positron emission tomography) has a great impact on current medical practice. It allows to explore, in a very precise way, different processes such as tissue flow and metabolism. Fluor-deoxyglucose labeled with F18 fluorine represents glucose metabolism. Among its main applications are detection, staging, follow up and recurrence assessment of malignant tumors; myocardial viability detection in patients with myocardial infarction or ischemic cardiomyopathy, and evaluation of hyperactive epileptogenic foci in brain. The basis and clinical applications of PET tomography are reviewed especially oriented to its cost benefit relationship, change in patient management and diagnostic value of the most accepted oncological indications. Important economic resources may be saved with PET in this field, considering appropriate staging and recurrence detection, avoiding expensive therapeutic approaches in advanced disease (Rev Med Chile 2002; 130: 569-79)

USO DE LA TOMOGRAFIA DE EMISION DE POSITRONES EN EL CANCER COLORRECTAL

Abstract: Abstract: The value of PET (Positron EmissionTomography) in colorectal cancer is presented. PETis a novel technique that uses F-18-FDG(fluorodeoxiglucose) to assess glucose metabolismby whole body imaging. It has been demonstratedthat malignant cells have both increase of glucoseuptake and utilization. In colorectal cancer, PET isindicated for staging, assess recurrence, livermetastasis and treatment follow-up. PET is moresensitive and specific than CT (ComputedTomography) and is cost effective. In 30% of casesPET may change patient management, avoidingunnecessary procedures.Key words:Key words: PET; F-18-FDG (fluorodeoxiglucose),Colorectal cancer.Resumen: Resumen: El valor de la tomografia de emision depositrones (PET) en el cancer colorrectal es revisa-do en esta corta comunicacion. El PET es una nue-va tecnica que emplea F-18-FDG (Fluoro-deoxiglucosa) para evaluar el metabolismo glucidicode las celulas mediante imagenes de todo el cuerpoen un solo examen. Se ha demostrado que las celu-las malignas tienen captacion y utilizacion aumenta-da de la glucosa. En el cancer colorrectal el PET estaindicado para el diagnostico de extension inicial, sos-pecha de recurrencia, evaluacion de metastasis he-paticas, recidiva tumoral y control de terapias. El PETes mas sensible y especifico que la tomografia com-putada y es una tecnica costo efectiva. En aproxi-madamente un 30% de los casos ayuda a cambiarel manejo terapeutico de los pacientes evitando pro-cedimientos innecesarios. Este ano entrara en fun-ciones un ciclotron en la Comision Chilena de Ener-gia Nuclear y la primera camara PET multicristal dealta resolucion de Chile y Sudamerica sera instaladaen el Hospital Militar de Santiago.Palabras claves:Palabras claves: PET; Cancer Colorrectal; F-18-FDG(fluorodeoxiglucosa).IntroduccionLa tomografia de emision de positrones (PET),es una tecnica de creciente utilizacion en la practicaclinica, en paises donde se encuentra disponible. Sebasa en el uso de radiofarmacos emisores depositrones, los cuales se unen a moleculas trazadorasde mecanismos fisiopatologicos como el flujo sangui-neo y metabolismo celular. La tabla I nos muestraalgunos de estos elementos, siendo el mas emplea-do la Fluor-18 FDG (fluorodeoxiglucosa), que nos in-forma acerca del metabolismo glucidico y se le em-plea en oncologia, cardiologia y neurologia

UTILIDAD DEL PET-FDG EN PATOLOGÍA GINECO-ONCOLÓGICA

SUMMARY FDG-PET is a whole body scan that evaluates glucose cell metabolism. Its main utility is in adult and children oncology. PET scan is useful differentiating benign from malignant neoplasm, selecting the site for biopsy, staging of the malignancy, evaluating response to therapy and distinguishing scar from residual neoplasm. Different studies have concluded that FDG-PET is a useful study in the gyneco-oncological management, especially in endometrial, cervical and ovarian cancer. This work reviews the principal indications of PET in this pathology and also the initial Chilean experience at the Military Hospital of Santiago with a dedicated PET, where we have studied more than 1,500 cases, most of them in cancer patients.