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objetivo Analizar la literatura disponible sobre el valor pronóstico de los parámetros metabólicos de la 18F-FDG PET/TC preoperatoria y su utilidad en la estratificación de riesgo en pacientes con cáncer de endometrio (CE). Material y métodos En búsquedas de Pubmed se utilizó «(endometr* OR uter*) AND (PET OR FDG)» como palabras clave desde enero-2000 hasta junio-2020. Se revisaron referencias en los artículos incluidos buscando posibles publicaciones no incluidas en la primera búsqueda. Se incluyeron los estudios que evaluaron el valor pronóstico de la 18F-FDG PET/TC preoperatoria y su papel para la estratificación del riesgo en pacientes con CE. Los artículos no originales (revisiones, editoriales, cartas, casos legales, entrevistas, informes de casos, etc.) no fueron incluidos. Resultados Veintiséis estudios (1.918 pacientes) fueron elegidos según los criterios de inclusión en esta revisión. Se incluyeron 13 estudios (939 pacientes) relacionados con el papel pronóstico de la 18F-FDG PET/TC preoperatoria y 14 estudios (1.036 pacientes) relacionados con su papel en la estratificación de riesgo. Parámetros como SUVmáx, volumen tumoral metabólico (VTM) y glicólisis total de lesión (GTL) del tumor primario fueron analizados. Conclusiones El SUVmáx preoperatorio es útil para realizar diagnósticos no invasivos y decidir la estrategia terapéutica adecuada, ya que podría utilizarse como marcador pronóstico independiente de recurrencia y supervivencia en el CE. Además, tanto VTM como GTL preoperatorios podrían ser factores pronósticos independientes para predecir recurrencia y supervivencia, pero, aun no existe suficiente evidencia científica. La utilidad del SUVmáx para la estratificación del riesgo es limitada (no existe literatura suficiente acerca de que la 18F-FDG PET/TC pueda sustituir la estadificación quirúrgica), aunque el VTM y la GTL sí que son más precisos y tienen un valioso papel en la estratificación del riesgo del CE (AU)
Objective To analyse the available literature on the prognostic value of preoperative 18F-FDG PET/CT metabolic parameters and their usefulness in risk stratification in patients with endometrial cancer (EC). Material and methods Pubmed searches used «(endometr* OR uter*) AND (PET OR FDG)» as keywords from January-2000 to June-2020. References in included articles were checked for possible publications not included in the first search. Studies evaluating the prognostic value of preoperative 18F-FDG PET/CT and its role for risk stratification in patients with EC were included. Non-original articles (reviews, editorials, letters, legal cases, interviews, case reports, etc.) were not included. Results Twenty-six studies (1918 patients) were selected according to the inclusion criteria in this review. Thirteen studies (939 patients) related to the prognostic role of preoperative 18F-FDG PET/CT and 14 studies (1036 patients) related to its role in risk stratification were included. Parameters such as SUVmax, metabolic tumour volume (MTV) and total lesion glycolysis (TLG) of the primary tumour were analysed. Conclusions Preoperative SUVmax is useful for non-invasive diagnosis and for deciding the appropriate therapeutic strategy, as it could be used as an independent prognostic marker for recurrence and survival in EC. In addition, both preoperative VTM and GTL could be independent prognostic factors for predicting recurrence and survival, but there is still insufficient scientific evidence. The usefulness of SUVmax for risk stratification is limited (there is insufficient literature that 18F-FDG PET/CT can replace surgical staging), although VTM and GTL are more accurate and have a valuable role in risk stratification of EC. However, larger multicentre studies with adequate follow-up time are needed to confirm these findings (AU)
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Humanos , Feminino , Neoplasias do Endométrio/diagnóstico por imagem , Neoplasias do Endométrio/cirurgia , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Medição de Risco , Liberação de Cirurgia , PrognósticoRESUMO
Objetivo: Como hay poca literatura sobre el tema, nos propusimos comparar la utilidad diagnóstica del análisis semicuantitativo versus el análisis visual en la escintigrafía de glóbulos blancos etiquetados (WBCS) para la infección osteoarticular. Se evaluaron protocolos de uno y dos días, en particular en los dispositivos ortopédicos.Material y métodos: Estudio prospectivo de 79 pacientes consecutivos con sospecha de infección osteoarticular. En todos los pacientes, la SCBM se realizó a los 30 min, 4 h, 8 h y 24 h. Las imágenes se analizaron agrupándolas en dos protocolos: protocolo de un día (los expertos evaluaron imágenes planas de 30 min, 4 h y 8 h) y protocolo de dos días (los expertos evaluaron imágenes planas de 30 min, 4 h y 24 h). Las imágenes planas se interpretaron cualitativa y semicuantitativamente y también se compararon agrupando a los pacientes con y sin dispositivos ortopédicos. Para determinar qué valor de corte de la variación porcentual podía predecir la infección osteoarticular, se calcularon múltiples valores de corte en ambos protocolos a partir del índice de Youden. Tres lectores ciegos analizaron las imágenes.Resultados: Comparando el diagnóstico final, el análisis visual del protocolo de un día proporcionó mejores resultados con una sensibilidad del 95,5%, una especificidad del 93% y una precisión diagnóstica del 93,7% (p < 0,01) que el protocolo de dos días con valores del 86,4%, 94,7% y 92,4%, respectivamente (p < 0,01). Para el análisis semicuantitativo, el protocolo de un día también obtuvo mejores resultados con una sensibilidad del 72,7%, una especificidad del 78,9% y una precisión del 77,2% (p < 0,01) que el protocolo de dos días (sin resultados significativos; p = 0,14), especialmente en el grupo de pacientes con aparatos ortopédicos (sensibilidad del 100%, especificidad del 79,5% y precisión del 82,7%; p < 0,01)
Objective: As scarce literature on the topic is available, we aimed to compare diagnostic utility of semi-quantitative versus visual analysis in labelled white blood cell scintigraphy (WBCS) for osteoarticular infection. One-day and two-day protocols were assessed, particularly in orthopaedic devices.Material and methods: Prospective study of 79 consecutive patients with suspected osteoarticular infection. In all patients, WBCS were performed at 30min, 4h, 8h and 24h. Images were analysed by grouping in two protocols: one-day-protocol (experts evaluated 30min, 4h and 8h planar images) and two-day-protocol (experts evaluated 30min, 4h and 24h planar images). Planar images were interpreted qualitative and semiquantitatively and also were compared grouping patients with and without orthopaedic devices. To find which cut-off value of the percentage variation could predict of osteoarticular infection, multiple cut-off values were calculated in both protocols from the Youden index. Three blinded readers analysed the images.Results: Comparing final diagnosis visual analysis of the one-day-protocol provided better results with sensitivity of 95.5%, specificity of 93% and diagnostic accuracy of 93.7% (P<.01) than the two-day-protocol with values of 86.4%, 94.7% and 92.4%, respectively (P<.01). For semi-quantitative analysis, the one-day-protocol also obtained better results with sensitivity of 72.7%, specificity of 78.9% and accuracy of 77.2% (P<.01) than two-day-protocol (no significant results; P=.14), especially in the group of patients with orthopaedic devices (sensitivity of 100%, specificity of 79.5% and accuracy of 82.7%; P<.01).Conclusions: Most accurate approach in the diagnosis of osteoarticular infection corresponded to visual analysis in one-day-protocol that showed greater sensitivity and specificity than semi-quantitative analysis. Semi-quantitative analysis only could be useful when visual analysis is doubtful
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Adulto Jovem , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Leucócitos , Doenças Ósseas Infecciosas/diagnóstico por imagem , Sensibilidade e Especificidade , Valor Preditivo dos Testes , Protocolos ClínicosRESUMO
OBJECTIVE: As scarce literature on the topic is available, we aimed to compare diagnostic utility of semi-quantitative versus visual analysis in labelled white blood cell scintigraphy (WBCS) for osteoarticular infection. One-day and two-day protocols were assessed, particularly in orthopaedic devices. MATERIAL AND METHODS: Prospective study of 79 consecutive patients with suspected osteoarticular infection. In all patients, WBCS were performed at 30min, 4h, 8h and 24h. Images were analysed by grouping in two protocols: one-day-protocol (experts evaluated 30min, 4h and 8h planar images) and two-day-protocol (experts evaluated 30min, 4h and 24h planar images). Planar images were interpreted qualitative and semiquantitatively and also were compared grouping patients with and without orthopaedic devices. To find which cut-off value of the percentage variation could predict of osteoarticular infection, multiple cut-off values were calculated in both protocols from the Youden index. Three blinded readers analysed the images. RESULTS: Comparing final diagnosis visual analysis of the one-day-protocol provided better results with sensitivity of 95.5%, specificity of 93% and diagnostic accuracy of 93.7% (P<.01) than the two-day-protocol with values of 86.4%, 94.7% and 92.4%, respectively (P<.01). For semi-quantitative analysis, the one-day-protocol also obtained better results with sensitivity of 72.7%, specificity of 78.9% and accuracy of 77.2% (P<.01) than two-day-protocol (no significant results; P=.14), especially in the group of patients with orthopaedic devices (sensitivity of 100%, specificity of 79.5% and accuracy of 82.7%; P<.01). CONCLUSIONS: Most accurate approach in the diagnosis of osteoarticular infection corresponded to visual analysis in one-day-protocol that showed greater sensitivity and specificity than semi-quantitative analysis. Semi-quantitative analysis only could be useful when visual analysis is doubtful. In patients with joint prostheses, an increase in percentage variation above 9% obtained maximum sensitivity and negative predictive value.
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PURPOSE: To investigate the capabilities of several variance reduction techniques in the calculation of specific absorbed fractions in cases where the source and the target organs are far away and/or the target organs have a small volume. METHODS: The specific absorbed fractions have been calculated by using the Monte Carlo code PENELOPE and by assuming the thyroid gland as the source organ and the testicles, the urinary bladder, the uterus, and the ovaries as the target ones. A mathematical anthropomorphic phantom, similar to the MIRD-type phantoms, has been considered. Photons with initial energies of 50, 100 and 500 keV were emitted isotropically from the volume of the source organ. Simulations have been carried out by implementing the variance reduction techniques of splitting and Russian roulette at the source organ only and the interaction forcing at the target organs. The influence of the implementation details of those techniques have been investigated and optimal parameters have been determined. All simulations were run with a CPU time of 1.5 · 105 s. RESULTS: Specific absorbed fractions with relative uncertainties well below 10% have been obtained in most cases, agreeing with those used as reference. The best value for the factor defining the application of the Russian roulette technique was r = 0.3. The best value for the splitting number was between s = 3 and s = 10, depending on the specific energies and target organs. CONCLUSIONS: The proposed strategy provides an effective method for computing specific absorbed fractions for the most unfavorable situations, with a computing effort that is considerably reduced with respect to other methodologies.
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Método de Monte Carlo , Radiometria/instrumentação , Processamento de Sinais Assistido por Computador , Glândula Tireoide/efeitos da radiação , Algoritmos , Antropometria , Simulação por Computador , Computadores , Feminino , Humanos , Masculino , Modelos Teóricos , Ovário/efeitos da radiação , Imagens de Fantasmas , Fótons , Doses de Radiação , Radiometria/métodos , Valores de Referência , Testículo/efeitos da radiação , Bexiga Urinária/efeitos da radiação , Útero/efeitos da radiaçãoRESUMO
AIM: Our aim was two-fold, to study the interobserver agreement in tumour segmentation and to search for a reliable methodology to segment gliomas using 18F-fluorocholine PET/CT. METHODS: 25 patients with glioma, from a prospective and non-randomized study (Functional and Metabolic Glioma Analysis), were included.Interobserver variability in tumour segmentation was assessed using fixed thresholds. Different strategies were used to segment the tumours. First, a semi-automatic tumour segmentation was performed, selecting the best SUVmax-% threshold for each lesion. Next we determined a variable SUVmax-% depending on the SUVmax. Finally a segmentation using a fixed SUVmax threshold was performed. To do so, a sampling of 10 regions of interest (ROI of 2.8cm2) located in the normal brain was performed. The upper value of the sample mean SUVmax±3 SD was used as cut-off. All procedures were tested and classified as effective or not for tumour segmentation by two observer's consensus. RESULTS: In the pilot segmentation, the mean±SD of SUVmax, SUVmean and optimal SUVmax-% threshold were: 3.64±1.77, 1.32±0.57 and 21.32±8.39, respectively. Optimal SUVmax-% threshold showed a significant association with the SUVmax (Pearson=-0.653, p=.002). However, the linear regression model for the total sample was not good, that supported the division in two homogeneous groups, defining two formulas for predicting the optimal SUVmax-% threshold. As to the third procedure, the obtained value for the mean SUVmax background+3 SD was 0.33. This value allowed segmenting correctly a significant fraction of tumours, although not all. CONCLUSION: A great interobserver variability in the tumour segmentation was found. None of the methods was able to segment correctly all the gliomas, probably explained by the wide tumour heterogeneity on 18F-fluorocholine PET/CT.
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Neoplasias do Sistema Nervoso Central/diagnóstico por imagem , Neoplasias do Sistema Nervoso Central/patologia , Fluordesoxiglucose F18 , Glioma/diagnóstico por imagem , Glioma/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Humanos , Variações Dependentes do Observador , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Estudos ProspectivosRESUMO
AIM: To analyze the relationship between measurements of global heterogeneity, obtained from 18F-FDG PET/CT, with biological variables, and their predictive and prognostic role in patients with locally advanced breast cancer (LABC). MATERIAL AND METHODS: 68 patients from a multicenter and prospective study, with LABC and a baseline 18F-FDG PET/CT were included. Immunohistochemical profile [estrogen receptors (ER) and progesterone receptors (PR), expression of the HER-2 oncogene, Ki-67 proliferation index and tumor histological grade], response to neoadjuvant chemotherapy (NC), overall survival (OS) and disease-free survival (DFS) were obtained as clinical variables. Three-dimensional segmentation of the lesions, providing SUV, volumetric [metabolic tumor volume (MTV) and total lesion glycolysis (TLG)] and global heterogeneity variables [coefficient of variation (COV) and SUVmean/SUVmax ratio], as well as sphericity was performed. The correlation between the results obtained with the immunohistochemical profile, the response to NC and survival was also analyzed. RESULTS: Of the patients included, 62 received NC. Only 18 responded. 13 patients relapsed and 11 died during follow-up. ER negative tumors had a lower COV (p=0.018) as well as those with high Ki-67 (p=0.001) and high risk phenotype (p=0.033) compared to the rest. No PET variable showed association with the response to NC nor OS. There was an inverse relationship between sphericity with DFS (p=0.041), so, for every tenth that sphericity increases, the risk of recurrence decreases by 37%. CONCLUSIONS: Breast tumors in our LABC dataset behaved as homogeneous and spherical lesions. Larger volumes were associated with a lower sphericity. Global heterogeneity variables and sphericity do not seem to have a predictive role in response to NC nor in OS. More spherical tumors with less variation in gray intensity between voxels showed a lower risk of recurrence.
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Neoplasias da Mama/diagnóstico por imagem , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Neoplasias da Mama/patologia , Feminino , Humanos , Imuno-Histoquímica , Estadiamento de Neoplasias , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Valor Preditivo dos Testes , PrognósticoRESUMO
AIM: To investigate the usefulness of metabolic variables using 18F-FDG PET/CT in the prediction of neoadjuvant chemotherapy (NC) response and the prognosis in locally advanced breast cancer (LABC). MATERIAL AND METHODS: Prospective study including 67 patients with LABC, NC indication and a baseline 18F-FDG PET/CT. After breast tumor segmentation, SUV variables (SUVmax, SUVmean and SUVpeak) and volume-based variables, such as metabolic tumor volume (MTV) and total lesion glycolysis (TLG), were obtained. Tumors were grouped into molecular phenotypes, and classified as responders or non-responders after completion of NC. Disease-free status (DFs), disease-free survival (DFS), and overall survival (OS) were assessed. A univariate and multivariate analysis was performed to study the potential of all variables to predict DFs, DFS, and OS. RESULTS: Fourteen patients were classified as responders. Median±SD of DFS and OS was 43±15 and 46±13 months, respectively. SUV and TLG showed a significant correlation (p<0.005) with the histological response, with higher values in responders compared to non-responders. MTV and TLG showed a significant association with DFs (p=0.015 and p=0.038 respectively). Median, mean and SD of MTV and TLG for patients with DFs were: 8.90, 13.73, 15.10 and 33.78, and 90.54 and 144.64, respectively. Median, mean and SD of MTV and TLG for patients with non-DFs were: 16.72, 29.70 and 31.09 and 90.89, 210.98 and 382.80, respectively. No significant relationships were observed with SUV variables and DFs. Volume-based variables were significantly associated with OS and DFS, although in multivariate analysis only MTV was related to OS. No SUV variables showed an association with the prognosis. CONCLUSION: Volume-based metabolic variables obtained with 18F-FDG PET/CT, unlike SUV based variables, were good predictors of both neoadjuvant chemotherapy response and prognosis.
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Neoplasias da Mama/diagnóstico por imagem , Radioisótopos de Flúor/análise , Fluordesoxiglucose F18/análise , Terapia Neoadjuvante , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Compostos Radiofarmacêuticos/análise , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/cirurgia , Terapia Combinada , Intervalo Livre de Doença , Feminino , Glicólise , Humanos , Estimativa de Kaplan-Meier , Metástase Linfática/diagnóstico por imagem , Mastectomia , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Carga TumoralRESUMO
AIM: To assess the diagnostic accuracy of 18F-FDG PET/contrast enhanced computed tomography (ceCT) in the detection of asymptomatic recurrences in patients with lymphoma. MATERIAL AND METHODS: Patients with lymphoma and clinical complete remission underwent 18F-FDG PET/ceCT for standard follow-up.18F-FDG PET and ceCT were evaluated blindly by two independent observers, and classified as positive or negative for recurrence. Additionally a combined evaluation of both techniques was performed. The final diagnosis was established by histopathological analysis or a clinical follow-up longer than 6 months. Statistical diagnostic parameters and concordance levels between both diagnostic techniques were calculated. RESULTS: A total of 114 explorations on 90 patients were analyzed. Only 4 patients were diagnosed as asymptomatic recurrence during the follow-up. 18F-FDG PET/ceCT, 18F-FDG PET and ceCT showed an association with the final diagnosis (p=0.002 and χ2=11.96; p<0.001 and χ2=15.60; p=0.001 and χ2=11.96, respectively). The concordance between 18F-FDG PET and ceCT was moderate/high and significant (kappa=0.672; p<0.001). A sensitivity and specificity of 50% and 88% was obtained for the 18F-FDG PET/ceCT civ, 50% and 93% for the 18F-FDG PET, and 50% and 91% for the ceCT. CONCLUSION: The combined use of 18F-FDG PET/ceCT did not offer any advantage compared to any isolated diagnostic technique in the detection of asymptomatic lymphoma recurrence.
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Linfoma/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Doenças Assintomáticas , Feminino , Radioisótopos de Flúor , Fluordesoxiglucose F18 , Seguimentos , Humanos , Masculino , Compostos Radiofarmacêuticos , Recidiva , Indução de Remissão , Estudos Retrospectivos , Sensibilidade e Especificidade , Método Simples-CegoRESUMO
OBJECTIVES: To study 18F-Choline PET/CT in the diagnosis and biopsy guide of prostate cancer (pCa) in patients with persistently high prostate-specific antigen (PSA) and previous negative prostate biopsy. To compare the clinical risk factors and metabolic variables as predictors of malignancy. METHODS: Patients with persistently elevated PSA in serum (total PSA >4ng/mL) and at least a previous negative or inconclusive biopsy were consecutively referred for a whole body 18F-Choline PET/CT. Patient age, PSA level, PSA doubling time (PSAdt) and PSA velocity (PSAvel) were obtained. PET images were visually (positive or negative) and semiquantitatively (SUVmax) reviewed. 18F-Choline uptake prostate patterns were defined as focal, multifocal, homogeneous or heterogeneous. Histology on biopsy using transrectal ultrasound-guided approach was the gold standard. Sensitivity (Se), specificity (Sp) and accuracy (Ac) of PET/CT for diagnosis of pCa were evaluated using per-patient and per-prostate lobe analysis. Receiver-operating-characteristic (ROC) curve analysis was used to assess the value of SUVmax to diagnose pCa. Correlation between PET/CT and biopsy results per-prostate lobe was assessed using the Chi-square test. Univariate and multivariate logistic regression analysis were applied to compare clinical risk factors and metabolic variables as predictors of malignancy. RESULTS: Thirty-six out of 43 patients with histologic confirmation were included. In 11 (30.5%) patients, pCa was diagnosed (Gleason score from 4 to 9). The mean values of patient age, PSA level, PSAdt and PSAvel were: 65.5 years, 15.6ng/ml, 28.1 months and 8.5ng/mL per year, respectively. Thirty-three patients had a positive PET/CT; 18 had a focal pattern, 7 multifocal, 4 homogeneous and 4 heterogeneous. Se, Sp and Ac of PET/CT were of 100%, 12% and 38% in the patient based analysis, and 87%, 29% and 14% in the prostate lobe based analysis, respectively. The ROC curve analysis of SUVmax showed an AUC of 0.568 (p=0.52). On a lobe analysis, poor agreement was observed between PET/CT findings and biopsy results (p=0.097). In the univariate/multivariate analysis, none of clinical and metabolic variables were statistically significant as predictor of pCa. CONCLUSION: Choline PET/CT is a suitable procedure for the detection of pCa in highly selected patients, however, a high rate of false positive should be expected.
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Adenocarcinoma/diagnóstico por imagem , Biópsia por Agulha/métodos , Biópsia Guiada por Imagem/métodos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Antígeno Prostático Específico/sangue , Neoplasias da Próstata/diagnóstico por imagem , Imagem Corporal Total , Adenocarcinoma/sangue , Adenocarcinoma/patologia , Idoso , Colina , Reações Falso-Positivas , Radioisótopos de Flúor , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Neoplasias da Próstata/sangue , Neoplasias da Próstata/patologia , Prostatite/diagnóstico por imagem , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: To investigate the relationship between maximum standardised uptake value (SUVmax) of ovarian lesions and histopathology subtypes, and their involvement in the response and prognosis of patients with epithelial ovarian carcinoma (EOC). MATERIAL AND METHODS: A retrospective analysis of 31 patients with EOC and 18F-FDG-PET/CT before treatment, including an assessment of the SUVmax of ovarian lesion. Histopathological diagnosis and follow-up was performed. A study was made on the relationship between the SUVmax and histological type (type I and II) and tumour stage, as well as the role of various parameters (SUVmax, histology, stage) on the patient outcomes (complete response [CR], overall survival [OS], disease-free survival [DFS], and disease-free [DF] status, at 12 and 24 months). RESULTS: The medium SUVmax in type I lesions was lower than in type II (6.3 and 9.3, respectively; P=.03). A 7.1 cut-off was set for SUVmax in order to identify type II EOC (sensitivity: 77.8%, specificity: 69.2%; AUC=0.748; P=.02). No significant relationship was found between tumour stage and SUVmax. CR was more common in early stages; relative risk (RR) of 1.64; P=.003, as well as in type I tumours and a lower SUVmax. Tumour stage was decisive in DFS (P=.04), LE24m (0.07) and OS (P=.08). Longer DFS and a higher percentage of DF 24m were observed in type I tumours (RR: 1.32; P=.26). CONCLUSIONS: SUVmax was related to EOC histology, so could predict the response and prognosis of these patients. No association was found between glycolytic activity of the primary tumor with the response and prognosis.
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Neoplasias Epiteliais e Glandulares/diagnóstico por imagem , Neoplasias Ovarianas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Epitelial do Ovário , Terapia Combinada , Intervalo Livre de Doença , Feminino , Radioisótopos de Flúor , Fluordesoxiglucose F18 , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Pessoa de Meia-Idade , Modelos Biológicos , Terapia Neoadjuvante , Neoplasias Epiteliais e Glandulares/etiologia , Neoplasias Epiteliais e Glandulares/patologia , Neoplasias Epiteliais e Glandulares/terapia , Neoplasias Ovarianas/etiologia , Neoplasias Ovarianas/patologia , Neoplasias Ovarianas/terapia , Ovariectomia , Prognóstico , Compostos Radiofarmacêuticos , Estudos RetrospectivosRESUMO
Currently in Chile, there are about 42 nuclear medicine centres that mainly use 99mTc and 131I in diagnostic and therapeutic procedures. Therefore, staff performs various tasks that increase the risk of internal incorporation and the need to implement routine monitoring programmes. This article shows tools for self-monitoring of staff who exposed to 131I from measurements in thyroid and urine samples, using the gamma cameras of Nuclear Medicine Units. Then, the calibration factors of gamma cameras of participating units were determined, and a one-worker dose was calculated due to internal incorporation, using an Excel spreadsheet for self-monitoring. The worker who handles 131I in one of the studied units was monitored for 6 months. The goal of this study is to implement a routine self-monitoring programme for the estimation of committed effective dose of staff exposed to 131I using gamma cameras in Nuclear Medicine Units of clinical centres in Chile.
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Medicina Nuclear , Exposição Ocupacional , Monitoramento de Radiação , Cintilografia , Chile , Câmaras gama , Humanos , Radioisótopos do Iodo , Glândula TireoideRESUMO
AIM: To analyze the relationship of clinical variables related to prognosis and tumor burden, with metabolic variables obtained in the staging (18)F-FDG PET/CT, and their value in the prognosis in follicular lymphoma (FL). METHODS: 82 patients with FL, a (18)F-FDG PET/CT at diagnosis and a follow-up for a minimum of 12 months, were retrospectively enrolled in the present study. Clinical variables (Tumor grade, Follicular Lymphoma International Prognostic Index (FLIPI) and Tumor burden) were evaluated. Metabolic variables such as SUVmax in the highest hypermetabolic lesion, extralymphatic locations, number of involved lymph node locations, bone marrow (BM) involvement, PET stage and diameter of the biggest hypermetabolic lesion, were analyzed in order to establish a PET score and classify the studies in low, intermediate and high metabolic risk. Clinical and metabolic variables (included metabolic risk) were compared. The relation among all variables and disease-free survival (DFS) was studied. RESULTS: The 28% of patients had a high-grade tumor. The 30.5% had FLIPI risk low, 29.3% intermediate y 40.2% high. The 42.7% presented a high tumor burden. The PET/CT was positive in 94% of patients. The tumor grade did not show significant relation with metabolic variable. FLIPI risk and tumor burden showed statistical relations with the SUV max and the PET score (p<0.008 and p=0.003 respectively). With respect to DFS, significant differences were detected for the PET stage and FLIPI risk (p=0.015 and p=0.047 respectively). FLIPI risk was the only significant predictor in Cox regression analysis, with a Hazard Ratio of 5.13 between high risk and low risk. CONCLUSION: The present research highlights the significant relation between metabolic variables obtained with FDG PET/CT and clinical variables although their goal as an independent factor of prognosis was not demonstrated in the present work.
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Fluordesoxiglucose F18 , Linfoma Folicular/diagnóstico por imagem , Linfoma Folicular/metabolismo , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Carga Tumoral , Adulto JovemAssuntos
Adjuvantes Imunológicos/uso terapêutico , Vacina BCG/uso terapêutico , Carcinoma de Células de Transição/terapia , Febre de Causa Desconhecida/etiologia , Recidiva Local de Neoplasia/terapia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Tuberculose/complicações , Neoplasias da Bexiga Urinária/terapia , Febre de Causa Desconhecida/diagnóstico por imagem , Fluordesoxiglucose F18 , Humanos , Masculino , Compostos Radiofarmacêuticos , Tuberculose/diagnóstico por imagemRESUMO
(99m)Tc-tetrofosmin single photon emission computed tomography ((99m)Tc-tetrofosmin SPECT) has an important role in the assessment of coronary artery disease. Despite being its main indication, this study does not only evaluate myocardial perfusion, but much more. Moreover, during the SPECT acquisition, the field area covered includes many important organs of the thorax and abdomen, so extracardiac abnormalities can be observed. The correct etiologic diagnosis of them is only possible if we understand how (99m)Tc-tetrofosmin works and make a comprehensive investigation of the clinical history of the patient.
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Artefatos , Refluxo Biliar/diagnóstico por imagem , Gastroplastia , Anamnese , Imagem de Perfusão do Miocárdio , Compostos Organofosforados/farmacocinética , Compostos de Organotecnécio/farmacocinética , Complicações Pós-Operatórias/diagnóstico por imagem , Compostos Radiofarmacêuticos/farmacocinética , Tomografia Computadorizada com Tomografia Computadorizada de Emissão de Fóton Único , Idoso , Carcinoma de Células Escamosas/diagnóstico por imagem , Carcinoma de Células Escamosas/secundário , Carcinoma de Células Escamosas/cirurgia , Dor no Peito/etiologia , Neoplasias Esofágicas/cirurgia , Esofagectomia , Reações Falso-Positivas , Conteúdo Gastrointestinal , Humanos , Masculino , Recidiva Local de Neoplasia/diagnóstico por imagem , Recidiva Local de Neoplasia/cirurgia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Distribuição TecidualRESUMO
OBJECTIVE: This study aimed to determine the diagnostic impact of (18)F-FDG PET/CT based on the clinical features of paraneoplastic neurological syndrome (PNS). MATERIAL AND METHODS: Multicenter retrospective and longitudinal study of patients with suspicion of PNS. The clinical picture was classified into classic (CS) and non-classic syndrome (NCS). After the follow-up, the definitive or possible diagnosis of PNS was established. The pictures that did not match any of the previous criteria were categorized as non-classifiable. The state of the onco-neural antibodies was studied. The PET/CT was classified as positive or negative for the detection of malignancy. The relationship between PET/CT findings and the final diagnosis was determined. The differences between variables (Pearson test X(2)) and the relationship between the results of the PET/CT and the final diagnosis were analyzed. RESULTS: A total of 64 patients were analyzed, classifying 30% as CS and 42% as NCS. After the follow-up, 20% and 16% of subjects were diagnosed as possible and definitive PNS, respectively. Positive onco-neural antibodies were found in 13% of the patients. A definitive diagnosis of PNS was associated with a positive PET/CT (P=.08). A significant relation between antibodies expression and final diagnosis of neoplasia (P=.04) was demonstrated. The PET/CT correctly localized malignancy in 5/7 cases of invasive cancer. CONCLUSIONS: The PET/CT showed a higher percentage of positive results in patients with definitive diagnosis of PNS. Despite the low prevalence of malignancy in our series, the PET/CT detected malignancy in a significant proportion of patients with invasive cancer.
Assuntos
Radioisótopos de Flúor , Fluordesoxiglucose F18 , Síndromes Paraneoplásicas do Sistema Nervoso/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Antineoplásicos/sangue , Diagnóstico Diferencial , Feminino , Seguimentos , Humanos , Encefalite Límbica/sangue , Encefalite Límbica/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Neoplasias/diagnóstico por imagem , Doenças do Sistema Nervoso/sangue , Doenças do Sistema Nervoso/diagnóstico , Doenças do Sistema Nervoso/diagnóstico por imagem , Síndromes Paraneoplásicas do Sistema Nervoso/sangue , Síndromes Paraneoplásicas do Sistema Nervoso/diagnóstico , Estudos RetrospectivosRESUMO
The purpose of the present work is to calculate specific absorbed fractions using variance reduction techniques and assess the effectiveness of these techniques in improving the efficiency (i.e. reducing the statistical uncertainties) of simulation results in cases where the distance between the source and the target organs is large and/or the target organ is small. The variance reduction techniques of interaction forcing and an ant colony algorithm, which drives the application of splitting and Russian roulette, were applied in Monte Carlo calculations performed with the code penelope for photons with energies from 30 keV to 2 MeV. In the simulations we used a mathematical phantom derived from the well-known MIRD-type adult phantom. The thyroid gland was assumed to be the source organ and urinary bladder, testicles, uterus and ovaries were considered as target organs. Simulations were performed, for each target organ and for photons with different energies, using these variance reduction techniques, all run on the same processor and during a CPU time of 1.5 · 10(5) s. For energies above 100 keV both interaction forcing and the ant colony method allowed reaching relative uncertainties of the average absorbed dose in the target organs below 4% in all studied cases. When these two techniques were used together, the uncertainty was further reduced, by a factor of 0.5 or less. For photons with energies below 100 keV, an adapted initialization of the ant colony algorithm was required. By using interaction forcing and the ant colony algorithm, realistic values of the specific absorbed fractions can be obtained with relative uncertainties small enough to permit discriminating among simulations performed with different Monte Carlo codes and phantoms. The methodology described in the present work can be employed to calculate specific absorbed fractions for arbitrary arrangements, i.e. energy spectrum of primary radiation, phantom model and source and target organs.
Assuntos
Absorção de Radiação , Algoritmos , Radiometria/métodos , Adulto , Análise de Variância , Humanos , Método de Monte Carlo , Imagens de Fantasmas , FótonsRESUMO
Anthropomorphic phantoms are used in nuclear medicine for imaging quality control, calibration of gamma spectrometry system for the study of internal contamination with radionuclides and for internal dosimetric studies. These are constructed of materials that have radiation attenuation coefficients similar to those of the different organs and tissues of the human body. The material usually used for the manufacture of phantoms is polymethyl methacrylate. Other materials used for this purpose are polyethylene, polystyrene and epoxy resin. This project presents the design and manufacture of an anthropomorphic thyroid-neck phantom that includes the cervical spine, trachea and oesophagus, using a polyester resin (ρ = 1.1 g cm(-3)). Its linear and mass attenuation coefficients were experimentally determined and simulated by means of XCOM software, finding that this material reproduces the soft tissue ICRU-44 in a range of energies between 80 keV and 11 MeV, with less than a 5 % difference.
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Medicina Nuclear/normas , Imagens de Fantasmas , Glândula Tireoide/diagnóstico por imagem , Chile , Simulação por Computador , Desenho de Equipamento , Humanos , Imageamento Tridimensional , Modelos Anatômicos , Pescoço/anatomia & histologia , Pescoço/diagnóstico por imagem , Exposição Ocupacional , Poliésteres , Polimetil Metacrilato , Controle de Qualidade , Doses de Radiação , Monitoramento de Radiação , Cintilografia , Resinas Sintéticas , Software , Glândula Tireoide/anatomia & histologiaRESUMO
Objetivo. Realizar una comparación entre 2 métodos para la valoración de la PET/TC a la mitad del tratamiento (PET/TC-mt) en linfomas, y establecer cuál de ellos predice con mayor precisión una respuesta metabólica completa (RMC) en la PET/TC al final del tratamiento (PET/TC-ft). Material y métodos. Análisis retrospectivo longitudinal de los estudios PET/TC de estadificación (PET/TC-e), PET/TC-mt y PET/TC-ft de 65 pacientes con linfoma, 35 linfoma de Hodgkin y 30 linfoma no Hodgkin. La PET/TC-mt fue realizada entre el segundo y cuarto ciclo de quimioterapia y se valoró utilizando 2 criterios de interpretación: criterio cualitativo (escala visual de 5 puntos), criterio semicuantitativo (porcentaje de diferencia entre el SUVmax de la lesión con mayor actividad metabólica en la PET/TC-e y la PET/TC-mt). Analizamos la probabilidad de obtener una RMC en la PET/TC-ft según la clasificación de la PET/TC-mt con estos 2 criterios. Resultados. Obtuvimos valores de sensibilidad (S), especificidad (E), valor predictivo positivo (VPP), valor predictivo negativo (VPN) y razón de probabilidad (RP) para el método cualitativo/semicuantitativo de 91/80%, 76,2/67%, 88,9/83,3%, 80/60,9% y 32/7,8% respectivamente, para predecir un RMC en la PET/TC-ft. No encontramos diferencias estadísticamente significativas entre la RP del análisis cualitativo y semicuantitativo (p=0,1942). Conclusión. Encontramos claras diferencias en la S, E, VPP y VPN entre ambos métodos de valoración de la PET/TC-mt para predecir una RMC en la PET/TC-ft. Sin embargo, al no encontrar diferencias estadísticamente significativas en la RP, no podemos afirmar que el método cualitativo sea superior al semicuantitativo para este fin (AU)
Objective. To compare two different methods for the interpretation of interim PET/CT (PET/CT-i) in lymphomas, and to establish which one best predicts a complete metabolic response (CMR) in the PET/CT study at the end of treatment (PET/CT-et). Material and Methods. Retrospective longitudinal analysis of the PET/CT studies for staging (PET/CT-s), PET/CT-i and PET/CT-et of 65 patients, 35 Hodgkin's lymphoma (HL) and 30 Non-HL. The PET/CT-i was performed between the second and fourth chemotherapy cycle. It was interpreted using two different criteria: qualitative criteria (5 point visual scale), semiquantitative criteria (percentage difference between the lesion with more SUVmax in the PET/CT-s and PET/CT-i). We analyzed the likelihood of obtaining a CMR in the PET/CT-et according to the results obtained on the PET/CT-i with these two criteria. Results. We obtained sensitivity (S), specificity (Sp), positive predictive values (PPV), negative predictive values (NPV) and likelihood ratio (LR) for the qualitative/semiquantitative method of 91%/80%, 76.2%/67%, 88.9%/83.3%, 80%/60.9% and 32%/7.8%, respectively, to predict a CMR in the PET/CT-et. There were no statistically significant differences between the LR of both methods (p=0.1942). Conclusion. We found clear differences in S, Sp, PPV and NPV between both interpretation criteria for the PET/CT-i to predict a CMR in the PET/CT-et. Nevertheless, we cannot confirm the superiority of the qualitative method over the semiqualitative method for this purpose as no statistically significance differences were found in their LR in our study (AU)
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Humanos , Masculino , Feminino , Adolescente , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/tendências , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Linfoma , Diagnóstico Precoce , Valor Preditivo dos Testes , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/estatística & dados numéricos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/normas , Estudos Retrospectivos , Estudos Longitudinais/métodos , Estudos Longitudinais , Sensibilidade e Especificidade , Curva ROCRESUMO
AIM: Our objective was to analyze all the rejected PET/CT-request forms (rf), its primary question to be answered and the impact of not performing the PET/CT studies for the management of the patients. MATERIAL AND METHODS: We retrospectively reviewed all the cancelled PET/CT-rf received in our department from January 2007 to June 2011. The reasons for cancelling were patient clinical status, request from referring physician, patient request and criteria of nuclear medicine physician. PET/CT-rf were classified according to the primary question to be answered. The clinical evolution of patients was followed up for 6 months after PET/CT was requested. RESULTS: Thirty-nine studies were cancelled due to the patient clinical situation (mainly advanced state of neoplastic disease), 46 due to request from referring physician, 18 by patient request and 74 PET/CT-rf were rejected due to nuclear medicine physician criteria. Thirty-four patients with a rejected PET/CT had known neoplastic history. The more prevalent primary questions to be answered were: evaluation of pulmonary (20) and bone lesions (13). Regarding pulmonary nodules, only 4 patients had previous neoplastic disease and their size was less than 5mm. The rejection of PET/CT studies did not cause any impact in the natural evolution of the disease of the patients. CONCLUSION: This procedure avoided unnecessary PET/CT scans reducing expenses and radiation without any detriment in the patients.
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Imagem Multimodal/estatística & dados numéricos , Tomografia por Emissão de Pósitrons/estatística & dados numéricos , Encaminhamento e Consulta/estatística & dados numéricos , Tomografia Computadorizada por Raios X/estatística & dados numéricos , Procedimentos Desnecessários/estatística & dados numéricos , Humanos , Estudos RetrospectivosRESUMO
Richter's syndrome (RS) refers to transformation of the chronic lymphoid leukemia (CLL) to a diffuse large cell lymphoma. Prognosis of patients with RS is generally considered unfavorable. We present two cases of patients with history of CLL, who had an increased of the lymphadenopathy, with elevated lactate dehydrogenase (LDH) in serum and increased (18)F-FDG uptake of the neck lymph nodes, with subsequent confirmation of RS by histology.
