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Tumor induced osteomalacia is uncommon and is characterized by an isolated and not PTH dependent reduction in tubular phosphate reabsorption. This alteration is produced by phosphaturic factors, such as fibroblast growth factor-23 (FGF-23) that are secreted by tumors. We report a 41 years old female presenting with joint pain and progressive loss of muscle strength in the lower limbs. Initial laboratory assessment showed hypophosphatemia, elevated alkaline phosphatases, normal intact parathormone levels, low levels of 25 hydroxy vitamin D and an elevated 24 h phosphaturia. Bone mineral density showed spine and femoral neck osteopenia. A positron emission tomography (PET) revealed a right thigh tumor with lung metastases. Its biopsy disclosed a fibrosarcoma. FGF-23 levels, measured by ELISA were markedly elevated. The patient was discharged with palliative measures.

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BACKGROUND: Clinical oncology is the main application of 18F-deoxyglucose (FDG) positron emission tomography (PET). AIM: To evaluate the first 1,000 patients studied with FDG PET in Chile. MATERIAL AND METHODS: Retrospective analysis of 1,000 patients (aged between 1 and 94 years, 550 females) studied with FDG PET, since 2003. All studies were performed in a high resolution Siemens Ecat-Exact HR (+). All reports were based on the visual analysis of three plane and three-dimensional images. RESULTS: Ninety seven percent of exams were done for oncological indications, mainly lung lesions, lymphoma, colorectal and gastroesophageal, cancer and breast tumors. Only 1% of patients had brain tumors. Non tumor neurological indications corresponded to 1.7%. Cardiac studies were only 0.3% and inflammatory process corresponded to 1%. The 5.6% corresponded to pediatric population. Six percent of patients were aged less than 18 years and in 50% of them, the indication was oncological, mainly lymphomas, brain tumors, endocrine cancers and sarcomas. The remaining 50% had a neurological indications, mainly for refractory epilepsy. CONCLUSIONS: PET FDG imaging was effective in the management of diverse diseases of children and adults.

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Background: Clinical oncology is the main application of 18F-deoxyglucose (FDG) positron emission tomography (PET). Aim: To evaluate the first 1,000 patients studied with FDG PET in Chile. Material and methods: Retrospective analysis of 1,000 patients (aged between 1 and 94 years, 550 females) studied with FDG PET, since 2003. All studies were performed in a high resolution Siemens Ecat-Exact HR (+). All reports were based on the visual analysis of three plane and three-dimensional images. Results: Ninety seven percent of exams were done for oncological indications, mainly lung lesions, lymphoma, colorectal and gastroesophageal, cancer and breast tumors. Only 1 percent of patients had brain tumors. Non tumor neurological indications corresponded to 1.7 percent. Cardiac studies were only 0.3 percent and inflammatory process corresponded to 1 percent. The 5.6 percent corresponded to pediatric population. Six percent of patients were aged less than 18 years and in 50 percent of them, the indication was oncological, mainly lymphomas, brain tumors, endocrine cancers and sarcomas. The remaining 50 percent had a neurological indications, mainly for refractory epilepsy. Conclusions: PET FDG imaging was effective in the management of diverse diseases of children and adults.

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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.

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Antecedentes: La angiografía coronaria es el estándar de oro para diagnosticar enfermedad coronaria. El objetivo de este trabajo fue comparar los resultados del SPECT con Talio 201 (²°¹ TI) con diversos valores de estenosis coronaria a la angiografía. Métodos: Se tabularon resultados de 145 pacientes. A todos ellos se les realizó un electrocardiograma (ECG) de esfuerzo, SPECT de perfusión miocárdica y angiografía coronaria. Para hacer la valorización se utilizaron 2 criterios angiográficos para estenosis coronaria: a) >50 por ciento y b) 75 por ciento, los que se aplicaron a los pacientes y vasos coronarios. Resultados: en la evaluación por pacientes la sensibilidad (S), especificidad (E) y exactitud (Ex) fue 87 por ciento, 57 por ciento y 81 por ciento, respectivamente, con criterio de estenosis de > 50 por ciento y de 93 por ciento, 51 por ciento y 79 por ciento usando criterio de > 75 por ciento, (NS). Al analizar los vasos individualmente la S, E y EX fue de 59 por ciento, 78 por ciento y 68 por ciento para criterio > 50 por ciento y de 70 por ciento, 75 por ciento y 74 por ciento para criterio > 75 por ciento (p<0.029 para S). Como era esperado a mayor severidad de estenosis, mayor incidencia de detección. Hubo 19 pacientes que presentaron estenosis entre 50 y 74 por ciento. De ellos 21 por ciento presentó ECG de estrés anormal y 58 por ciento SPECT de perfusión miocárdica anormal. Conclusión: Los resultados con el estudio de perfusión miocárdica con ²°¹TI avalan el uso de valor de 50 por ciento o más de estenosis angiográfica en el diagnóstico y evaluación de la enfermedad coronaria. En conjunto con la angiografía coronaria. El SPECT miocárdico ofrece una excelente estrategia para el manejo de los pacientes.

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We report a 38 years old female patient with a pancreatic mucinous cystadenocarcinoma. She presented at the onset with a peritoneal rupture that required emergency surgery. Five months later, the patient was subjected to a segmental pancreatectomy and splenectomy. One year later, the patient had a serious gastric bleeding secondary to a gastric ulcer. Due to a persistent increase in her CA 19-9 levels, a Positron Emission Tomography (PET) functional imaging with fluorine 18-deoxyglucose (F18FDG) was done. It showed an intense focal hypermetabolism in the gastric wall reported as a secondary tumour location. The patient was subjected to a total gastrectomy and Roux en Y anastomosis, with a good outcome. The pathological study confirmed the presence of a metastasis of an adenocarcinoma in the gastric wall. The relative value of CA 19-9 markers and FDG PET in pancreatic and gastric carcinomas is discussed (Rev MÚd Chile 2004; 132: 347-52).

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Background. Detecting viability is important after recent myocardial infarction (MI). SPECT FDG/Tl flow-metabolism patterns for predicting functional recovery were analyzed in this setting. Method. Forty-one patients were studied (56ñ12 years; 80 percent males) with Tl 201 at rest and FDG F18 SPECT at a mean of 8.9 days post MI (range:1-24). All had baseline and 3 month follow-up echocardiography (ECHO) and initial coronary angiography. They were submitted to primary PTCA in 12 cases, late PTCA in 15 and bypass surgery in 10 and thrombolysis was performed in 4 patients as only procedure. A total of 345 culprit artery territory segments were interpreted by 3 nuclear independent observers. Analysis included segments with or without abnormal motion. Results. FDG/Tl 201 on patient basis, had: sensitivity 91percent; specificity 56 percent; positive predictive value 88 percent; negative predictive value (NPV) 63 percent and accuracy 83 percent. The analysis of segments with abnormal contractility showed values of 67 percent, 69 percent, 44 percent, 85 percent and 68 percent, respectively. Reverse mismatch with FDG/Tl appears to predict viability similarly to classical mismatch; severe or moderate match was highly associated with no functional recovery (NPV = 85 percent). Conclusion. Flow-perfusion patterns are variable in recent MI. FDG/Tl 201 SPECT has acceptable accuracy for predicting functional recovery and excellent NPV to further exclude viability

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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.

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The value of PET (Positron Emission Tomography) in colorectal cancer is presented. PET is a novel technique that uses F-18-FDG (fluorodeoxiglucose) to assess glucose metabolism by whole body imaging. It has been demonstrated that malignant cells have both increase of glucose uptake and utilization. In colorectal cancer, PET is indicated for staging, assess recurrence, liver metastasis and treatment follow-up. PET is more sensitive and specific than CT (Computed Tomography) and is cost effective. In 30% of cases PET may change patient management, avoiding unnecessary procedures.

El valor de la tomografía de emisión de positrones (PET) en el cáncer colorrectal es revisado en esta corta comunicación. El PET es una nueva técnica que emplea F-18-FDG (Fluoro-deoxiglucosa) para evaluar el metabolismo glucídico de las células mediante imágenes de todo el cuerpo en un solo examen. Se ha demostrado que las células malignas tienen captación y utilización aumentada de la glucosa. En el cáncer colorrectal el PET esta indicado para el diagnóstico de extensión inicial, sospecha de recurrencia, evaluación de metástasis hepáticas, recidiva tumoral y control de terapias. El PET es más sensible y específico que la tomografía computada y es una técnica costo efectiva. En aproximadamente un 30% de los casos ayuda a cambiar el manejo terapéutico de los pacientes evitando procedimientos innecesarios. Este año entrará en funciones un ciclotrón en la Comisión Chilena de Energía Nuclear y la primera cámara PET multicristal de alta resolución de Chile y Sudamérica será instalada en el Hospital Militar de Santiago.

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Background: Exercise EKG is used as the test of choice in the diagnosis of coronary artery disease. Classical parameters are angor and ST depression representing myocardial ischemia. Aim: To correlate exercise EKG parameters with SPECT 201Thallium to know their likelihood ratios for ischemia. Patients and methods: Two hundred seventy four patients (171 men), aged 58 years old as a mean, were studied. Of these, 23 percent had a prior myocardial infarction. The likelihood ratios for the presence of ischemia of ST depression, failure to increase blood systolic pressure, the presence of angor and its duration during stress testing were calculated according to the results of SPECT 201Thallium. Seventy one patients were also subjected to a coronary angiography. Results: Among men, likelihood ratios for the presence of angor, failure to increase systolic pressure, ST alterations and duration of angor were 6.9, 6.15, 1.77 and 1.27 respectively. Among women, the figures were 5.45, 1.77, 0.58 and 1.4 respectively. The diagnostic accuracy of SPECT 201Thallium, when correlated with the results of coronary angiography, was 85 percent. Conclusions: Among men, the best exercise EKG predictors for myocardial ischemia were the failure to increase systolic blood pressure and the presence of angor. Among women the only significant predictor was the presence of angor

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Entre los años 1983 y 1992 practicamos 104 gastrectomías totales en pacientes con cáncer gástrico. La localización tumoral fue 8,7 porciento en tercio inferior, 40,4 porciento en el tercio medio y 50,9 porciento en el tercio superior. En 81 casos hicimos esplenectomía o pancreatoesplenectomía (78 porciento). Las complicaciones postoperatorias se presentaron en el 36,5 porciento de estos pacientes. Hubo sólo 6 muertes hospitalarias (5,7 porciento), 5 fístulas de la anastomosis esófagoyeyunal (4,8 porciento), 8 abscesos subfrénicos (7,7 porciento), 16 complicaciones respiratorias (15,4 porciento) y otras complicaciones en 14 pacientes (13,4 porciento)

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We studied left ventricular perfusion and motility in 37 patients with coronary artery disease and disturbances of parietal motility, aged 57 ñ 9 years old, before and after revascularization. Perfusion was assessed with dipyridamole-Tc99m SPECT and motility was assessed with 2 dimentional echocardiography with amrinone. Myocardial segments were defined as normal, viable or necrotic in both studies. Eighteen subjects were subjected to angioplasty and 19 to coronary bypass surgery. Submitted SPECT and echography were repeated 64 ñ 15 and 69 ñ 23 days after revascularization respectively. The concordance between SPECT and echocardiographic prerevascularization diagnosis was 60.1 percent. Eighty one percent of segment considered viable with SPECT and 71 percent thus considered with echocardiography improved after revascularization. Likewise, 50 percent of segments considered necrotic with SPECT and 68 percent of segment thus considered with echocardiography did not improve. It is concluded that althought there is a good concordance between both methods, they have limitations on the study of myocardial viability and should be considered as second choice

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