Musculoskeletal pitfalls in 68Ga-PSMA PET/CT / Pitfalls do sistema musculoesquelético na PET/CT com 68Ga-PSMA

Abstract Prostate-specific membrane antigen (PSMA) is a transmembrane protein expressed in normal prostate cells and overexpressed in prostate cancer. Consequently, it is an important tool in the evaluation of prostate cancer, including the staging of high-risk patients and the assessment of biochemical recurrence. Despite the "specific" designation, benign musculoskeletal conditions, such as fractures, osteodegenerative changes, and fibrous dysplasia, can also show PSMA uptake, which can lead to misinterpretation of the imaging findings. Therefore, radiologists must be aware of these potential pitfalls, understand their causes, and fully analyze their morphologic features on unfused computed tomography (CT) and magnetic resonance imaging scans to correctly interpret the examination. In this pictorial essay, we review the basic characteristics of the 68Ga-PSMA positron-emission tomography/CT (PET/CT) radiotracer, discuss potential causes of false-positive findings on 68Ga-PSMA PET/CT in the musculoskeletal system, and illustrate the corresponding imaging findings.

Resumo O antígeno de membrana próstata específico (PSMA) é uma proteína transmembrana que apresenta expressão em células prostáticas normais e superexpressão em neoplasia da próstata. Dessa forma, é uma importante ferramenta na avaliação da neoplasia prostática, de utilidade no estadiamento de pacientes de alto risco e na análise de recorrência bioquímica. Apesar do termo "específico", condições musculoesqueléticas benignas podem demonstrar captação de PSMA, como fraturas, alterações osteodegenerativas e displasia fibrosa, podendo levar a uma avaliação equivocada dos achados de imagem. Assim, o radiologista deve conhecer esses potenciais pitfalls, compreender suas causas e analisar as características morfológicas nas imagens não fundidas de TC e RM para interpretar corretamente o exame. Neste ensaio iconográfico, revisaremos as características básicas do radiofármaco 68Ga-PSMA PET/CT, discutiremos possíveis causas de resultados falso-positivos na 68Ga-PSMA PET/CT no sistema musculoesquelético e ilustraremos os achados de imagem correspondentes.

Efeito do mesilato de desferroxamina e de sua associação com o maltolato de gálio na replicação do Mycobacterium leprae / EFFECT OF DESFERRIOXAMINE MESYLATE AND ITS ASSOCIATION WITH GALLIUM MALTOLATE ON THE REPLICATION OF MYCOBACTERIUM LEPRAE

A hanseníase é uma doença infecto-contagiosa, granulomatosa de evolução crônica, causada pelo Mycobacterium leprae. A introdução da poliquimiterapia pela Organização Mundial da Saúde em 1981, resultou na cura de milhões de indivíduos infectados pelo bacilo, no entanto ela ainda é considerada endêmica e negligenciada em países como o Brasil. A indústria farmacêutica não tem mostrado interesse em investir na pesquisa de novos fármacos, porém novas opções terapêuticas são importantes para o controle da endemia. Uma das alternativas de terapia para infecções que são causadas por microrganismos intracelulares é o bloqueio de ferro. Este metal tem grande importância na replicação dos patógenos no hospedeiro então, o uso de quelantes para a redução da carga parasitaria é uma das possibilidades estudadas. Um dos compostos utilizados como quelante do ferro é o mesilato de desferroxamina (DFX), que tem atividade antimicrobiana e vem sendo estudado no tratamento de diversas doenças como a talassemia. O maltolato de gálio também é um quelante capaz de se ligar ao ferro, competindo em sua via metabólica. O objetivo do estudo foi avaliar o efeito do DFX, administrado sozinho ou em associação com o maltolato de gálio, na replicação do Mycobacterium leprae em modelo experimental murino. Os camundongos infectados foram divididos em três grupos (controle, DFX e DFX + gálio) e o tratamento teve início 60 dias após a inoculação sendo administrado por 90 dias. Os animais receberam ração com restrição de ferro e água ad libitum. A suspensão do maltolato de gálio (150mg/kg) foi administrada diariamente via oral por gavage. O DFX foi aplicado por via intraperitoneal na concentração de 10 mg/kg, uma vez por semana durante cinco semanas. Os camundongos foram eutanasiados após 150 e 240 dias após inoculação. Em relação ao primeiro tempo de eutanásia (150 dias), não houve diferença estatisticamente significativa entre o número de bacilos recuperados entre o controle e os animais tratados; após 240 dias, houve diferença estatisticamente significativa (p<0,05) entre o número de bacilos recuperados entre o grupo controle e os animais tratados com DFX e DFX + gálio oral (p<0,0088 e p<0,0032 respectivamente). Os resultados mostraram que o uso de quelantes de ferro como o DFX e o gálio oral não impediram a replicação do bacilo, mas contribuiram para a diminuição da quantidade recuperada (carga bacilar).

Leprosy is an infectious, contagious, granulomatous disease of chronic evolution, caused by Mycobacterium leprae. The introduction of multidrug therapy by the World Health Organization in 1981 resulted in the cure of millions of individuals infected by the bacillus, however it is still considered endemic and neglected in countries like Brazil. The pharmaceutical industry has not shown interest in investing in the research of new drugs, but new therapeutic options are important for controlling the endemic disease. One of the therapy alternatives for infections that are caused by intracellular microorganisms is iron blockade. This metal is of great importance in the replication of pathogens in the host, so the use of chelators to reduce the parasite load is one of the possibilities studied. One of the compounds used as a iron chelator is desferrioxamine mesylate (DFX), which has antimicrobial activity and has been studied in the treatment of various diseases such as thalassemia. Gallium maltolate is also a chelator capable of binding to iron, competing in its metabolic pathway. The objective of the study was to evaluate the effect of DFX, administered alone or in association with gallium maltolate, on the replication of Mycobacterium leprae in a murine experimental model. Infected mice were divided into 3 groups (control, DFX and DFX + gallium) and treatment started 60 days after inoculation and was administered for 90 days. The animals received iron-restricted chow and water ad libitum. The suspension of gallium maltolate (150mg/kg) was administered orally daily by gavage. DFX was applied intraperitoneally at a concentration of 10 mg/kg, once a week for five weeks. The mice were euthanized after 150 and 240 days after inoculation. Regarding the first time of euthanasia (150 days), there was no statistically significant difference between the number of bacilli recovered between the control and treated animals; after 240 days, there was a statistically significant difference (p<0.05) between the number of bacilli recovered between the control group and the animals treated with DFX and DFX + oral gallium (p<0.0088 and p<0.0032 respectively). The results showed that the use of iron chelators such as DFX and oral gallium did not prevent the bacillus from replicating, but contributed to a decrease in the amount recovered (bacillary load).

Effectiveness of the therapeutic laser in the syndrome of dysfunction of the temporomandibular joint of arthrogenic origin / Eficacia del láser terapéutico en el síndrome de disfunción de la articulación temporomandibular de origen artrogénico

Abstract Temporomandibular joint dysfunction syndrome (TMD), is a collective term characterized by symptoms involving chewing muscles, temporomandibular joint and orofacial structures. The efficacy of low intensity laser (LLLT) Gallium arsenide, in combination with a non-steroidal anti-inflammatory drug (NSAID) was evaluated. The main objective was to evaluate the maximum mouth opening without pain (ABM), arthralgia in the joint capsule through visual analog scale (VAS), laterality, protrusion, joint noises and count of tablets ingested per group. A controlled clinical trial (double-blind-randomized) was carried out in 30 subjects, who presented DTM of arthrogenic etiology; 5 applications of LLLT were made with wavelength of 810 nm, output optical power of 100-200 mw, emission PW=Pulsed (1-10,000Hz), dose of 10 jouls-cm², time of 1.44 minutes in mouth closed and with the mouth half open. One more follow-up appointment per month. There were two groups: experimental and control group, where different variables were analyzed (ABM, laterality, protrusion, VAS and sociodemographic). In the control group, a supposed LT application (not active) was made, for later comparison. Pain-free ABM was assessed in all appointments in addition to the other clinical parameters. Repeated measures analysis was performed with mixed models. Thirty patients were included of which 28 finished the treatment, two of them were lost during follow-up. The groups were similar in all their baseline variables. There were no statistically significant differences when applying the final multiple regression analysis, in the ABM, or in any other of the clinical parameters analyzed. LT was not effective in treating arthrogenic DTM.

Resumen El síndrome de disfunción de la articulación temporomandibular (DTM) es un término colectivo caracterizado por síntomas que involucran músculos de la masticación, articulación temporomandibular y estructuras orofaciales. Se evaluó la eficacia del láser de baja intensidad (LLLT) Arseniuro de galio, en combinación con un antiinflamatorio no esteroideo (AINE). El objetivo principal fue evaluar la apertura bucal máxima sin dolor (ABM), la artralgia en cápsula articular a través de escala visual análoga (EVA), lateralidades, protrusión, ruidos articulares y conteo de tabletas ingeridas por grupo. Se realizó un ensayo clínico controlado (doble ciego-aleatorizado) en 30 sujetos, que presentaban DTM de etiología artrogénica; se les realizaron 5 aplicaciones de LLLT con longitud de onda de 810 nm, potencia óptica de salida de 100-200 mw, emisión PW=Pulsed (1-10,000Hz), dosis de10 jouls-cm², tiempo de1.44 minutos a boca cerrada y con la boca semiabierta. Una cita más de seguimiento al mes. Se tuvieron dos grupos: experimental y grupo control, donde se analizaron diferentes variables (ABM, lateralidades, protrusión, EVA y sociodemográficas). En el grupo control se hizo una supuesta aplicación LT (no activo), para posterior comparación. En todas las citas se valoró la ABM sin dolor además de los otros parámetros clínicos. Se realizó análisis de medidas repetidas con modelos mixtos. Se incluyeron 30 pacientes de los cuales 28 finalizaron el tratamiento, dos de ellos se perdieron en el seguimiento. Los grupos fueron similares en todas sus variables basales. No hubo diferencias estadísticas significativas al aplicar los análisis de regresión múltiple finales, en la ABM, ni tampoco en ningún otro de los parámetros clínicos analizados. El LT no fue eficaz en el tratamiento de la DTM de origen artrogénico.

Hallazgos histológicos asociados a gingivectomía con láser de Er, Cr: YSGG (2780 nm) / Histological Findings' Associated with Gingivectomy with Er, Cr: YSGG (2780 nm) Laser

RESUMEN Introducción: Al realizar una intervención quirúrgica, el instrumento de corte utilizado cobra especial importancia, pues el mismo está vinculado a los signos y síntomas intra- y posoperatorios y al tiempo de reparación de los tejidos. En respuesta a esto, con el tiempo se han propuesto nuevos instrumentos, particularmente la tecnología láser ha venido sufriendo un avance rápido y significativo y en la actualidad se utiliza para un sinnúmero de tratamientos odontológicos. Al láser se le han atribuido diferentes ventajas en la cirugía estética periodontal: desde facilitar el proceso de hemostasia, hasta la estimulación del proceso de reparación tisular. Sin embargo, es pertinente realizar estudios que demuestren a nivel histológico los cambios que generan en la mucosa oral y obtener información que permita conocer de qué manera influye en el proceso de reparación del tejido. Objetivo: Describir los hallazgos histológicos asociados al corte con láser de Er, Cr: YSGG de 2780 nm en muestras de encía obtenidas mediante gingivectomía. Presentación del caso: Paciente femenina, de 21 años, sistémicamente sana. Asistió a la consulta por presentar por inconformidad estética al sonreír. Se diagnosticó con exposición de banda de encía queratinizada mayor que 4 mm. Como parte del plan de tratamiento se indicó gingivectomía con láser de Er, Cr: YSGG (2780 nm) (Waterlase®, BIOLASE®), el procedimiento se realizó solo bajo anestesia tópica. Se tomaron muestras histológicas de tejido gingival para análisis histológico. Conclusiones: El láser Er, Cr: YSGG (2780 nm) preservó la morfología de los fibroblastos después del corte, no hubo evidencia de carbonización, ni profundización de la lesión térmica en el tejido. Este instrumento fue una herramienta de gran utilidad para la ejecución del tratamiento en este caso. Tuvo ventajas importantes como la ausencia de dolor posoperatorio, buena hemostasia y la reparación epitelial casi completa en tan solo 4 días(AU)

ABSTRACT Introduction: When performing a surgical intervention, the cutting instrument used is especially important, since it is associated with intraoperative and postoperative signs and symptoms and to the time of tissue repair. In response to this, new instruments have been proposed over time, particularly laser technology has been undergoing rapid and significant advancement and is currently used for countless dental treatments. Laser has been attributed different advantages in periodontal cosmetic surgery: from facilitating the hemostasis process, to stimulating the tissue repair process. However, it is pertinent to carry out studies that prove, at histological level, the changes in the oral mucosa and obtain information that allows us to know how it influences the tissue repair process. Objective: To describe the histological findings associated with the Er, Cr: YSGG (2780 nm) laser cut in gum samples obtained by gingivectomy. Case presentation: Female patient, 21 years old, systemically healthy. She attended the consultation for presenting aesthetic dissatisfaction when smiling. She was diagnosed with exposure of keratinized gum band greater than 4 mm. As part of the treatment plan, Er, Cr: YSGG (Waterlase®, BIOLASE®, 2780 nm) laser gingivectomy was indicated. The procedure was performed only under topical anesthesia. Histological samples of gingival tissue were taken for histological analysis. Conclusions: The Er, Cr: YSGG (2780 nm) laser preserved the morphology of the fibroblasts after the cut. There was no evidence of carbonization or deepening of the thermal injury in the tissue. In this case, this instrument was a very useful tool for the performance of the treatment. It had important advantages, such as the absence of postoperative pain, good hemostasis, and almost complete epithelial repair in just four days(AU)

[Rebound (reactive) thymic hyperplasia after chemotherapy in children with lymphoma]. / Hiperplasia tímica de rebote posquimioterapia en niños con linfoma.

INTRODUCTION: Thymic regrowth after chemotherapy treatment has been reported in children with lymphoma, and in order to avoid misdiagnosing these cases as relapses, physicians should become familiar with rebound (reactive) thymic hyperplasia (RTH) and remain aware of its possible occurrence. We aimed to estimate the prevalence of RTH in children with lymphoma after completion of chemotherapy and to evaluate the clinical characteristics, outcomes, and the findings of computed tomography (CT) and gallium-67 (GA-67) scans in these patients. PATIENTS AND METHODS: We conducted a retrospective cross-sectional study by reviewing the health records of children with a lymphoma diagnosis managed at an outpatient paediatric oncology clinic in Jeddah, Saudi Arabia. RESULTS: Rebound thymic hyperplasia was detected in 51.9% of the lymphoma patients (14/27). It developed a median of 2.5 months after completion of chemotherapy (range, 2.0-4.25 months). Patients with RTH had significantly shorter treatment durations, and we found no significant differences between patients with and without RTH in sex, age at diagnosis, type of lymphoma or type of treatment received. All patients with RTH were asymptomatic, and routine laboratory tests did not detect any abnormalities in them. The findings of CT and GA-67 scans were highly suggestive of RTH. None of the patients with RTH had a recurrence, and RTH resolved spontaneously within a median of 6 months (range, 4.0-11.0). CONCLUSION: RTH was detected in ∼50% of children with lymphoma after completion of chemotherapy. A clinical evaluation and laboratory tests combined with imaging by CT and GA-67 can help identify RTH and rule out other lesions elsewhere.

Analysis of radiation effects on some properties of GaAs:Cr and Si sensors exposed to a 22 MeV electron beam / Análisis de los efectos de la radiación en algunas propiedades de sensores de GaAs:Cr y Si expuestos a un haz de electrones de 22 MeV

Abstract Nowadays, the experiments related to High Energy Physics and others fields demand the use of detectors with greater radiation resistance, and the novel material GaAs:Cr has demonstrated excellent radiation hardness compared with other semiconductors. On the basis of evidence obtained in the JINR experiment with the use of 22 MeV electrons beam generated by the LINAC-800 accelerator, an analysis of electron radiation effects on GaAs:Cr and Si detectors is presented. The measured I-V characteristics showed a dark current increase with dose, and an asymmetry between the two branches of behaviors for all detectors. Analyzing the MIP spectra and CCE dose dependence measurements a deterioration process of detectors collection capacity with dose increase was found, although behaviors are somewhat different according to the detector type. The detailed explanation of these effects from the microscopic point of view appears in the text, and are generally linked to the generation of atomic displacement, vacancies and other radiation defects, modifying the energy levels structure of the target material. These changes affect the lifetime and concentration of the charge carriers, and other characteristics of the target material.

Resumen Actualmente, los experimentos relacionados con la física de altas energías y otros campos, demandan el uso de detectores con mayor resistencia a las radiaciones y el novedoso material GaAs:Cr ha demostrado poseer una excelente fortaleza comparado con otros semiconductores. En base a las evidencias obtenidas en el experimento del IUIN con el uso de un haz de electrones de 22 MeV generado por el acelerador LINAC-800, se presenta un análisis de los efectos de la radiación en detectores de Si y GaAs:Cr. Las características I-V medidas mostraron un incremento de la corriente de fuga con la dosis y una asimetría entre las dos ramas de estos comportamientos para todos los detectores. Analizando las mediciones de los espectros MIP y la dependencia de la CCE con la dosis, fue encontrado un proceso de deterioro de la capacidad de detección de los detectores con el aumento de la dosis, sin embargo, los comportamientos son diferentes de acuerdo al tipo de detector. La explicación detallada de estos efectos desde el punto de vista microscópico aparece en el texto, los cuales están relacionados generalmente con la generación de desplazamientos atómicos, vacancias y otros defectos producto de la radiación, modificando la estructura de los niveles energéticos en el material sensor. Estos cambios afectan el tiempo de vida y la concentración de los portadores de carga, así como otras características del material.

Monte Carlo simulation of the radiation transport in chromium compensated gallium arsenide detectors / Simulación por Monte Carlo del transporte de las radiaciones en detectores dearseniuro de galio compensado con cromo

Abstract Some results obtained with the use of Monte Carlo mathematical simulation of radiation transport in Timepix hybrid detectors based on chromium compensated gallium arsenide are presented in this contribution. The MCNPX, GEANT4, SRIM and MCCM code systems were used for this purpose. The in-depth profiles of the deposited energy by the incident photons within the sensor active volume, the shapes and dimensions of the generated charge carriers clouds for different incident energies and specific geometrical conditions were obtained and presented. The 22Ne ions ranges in the target material for two different energies and the contributions of each energy loss channel were also determined. Finally, for a selected detector irradiated with photons of different energies, the displacement cross sections for each chemical element in the active material, as well as the number of displacements per atoms produced for each atomic species were calculated.

Resumen En este trabajo se presentan algunos de los resultados obtenidos con el uso de la modelación matemática por Monte Carlo del transporte de radiación en detectores híbridos Timepix basados en el arseniuro de galio compensado con cromo. Se emplearon para este propósito los sistemas de códigos MCNPX, GEANT4, SRIM y MCCM. Fueron obtenidos los perfiles en profundidad de la energía depositada por la radiación incidente dentro del volumen activo del sensor, las formas y dimensiones de las nubes de portadores de cargas generados por fotones incidentes de diferentes energías y condiciones geométricas específicas. También se determinaron los alcances de los iones de 22Ne de dos energías diferentes en el material blanco y las contribuciones de cada canal de pérdida de energía. Finalmente, para un detector seleccionado irradiado con fotones de diferentes energías se calcularon las secciones eficaces de desplazamiento para cada elemento químico en el material activo, así como el número de desplazamientos por átomos producidos para cada especie atómica.

67-Gallium SPECT/CT in febrile syndromes of unknown origin. / SPECT/TC con galio-67 en los síndromes febriles sin foco conocido.

INTRODUCTION AND OBJECTIVE: Febrile syndromes of unknown origin (FSUO) are complex processes in hospital practice. Their management includes an exhaustive medical history and examination, as well as an extensive number of biochemical tests. If these are inconclusive, diagnostic imaging techniques such as SPECT/CT with 67-Gallium Citrate (67Ga-SPECT/CT) could play an important role. We evaluated its role in the management of FSUO in our healthcare area. MATERIAL AND METHODS: We reviewed 57 patients who underwent a 67Ga-SPECT/CT due to a FSUO (32 women and 25 men, age range: 32-83 years old) obtaining scintigraphic findings, previous treatments and final diagnosis. Values of sensitivity, specificity, positive predictive values (VPP) and negative values (NPV) were obtained and compared with the results for PET/CT with 18Fluor-deoxy-glucose (18F-FDG PET/CT) found in the literature. RESULTS: The diagnoses found were: infection in 27/57 (47%), inflammatory disease in 15/57 (26%), neoplasm in 1/57 (1.75%) and patients without final diagnosis in 14/57 (24%). The statistical values of 67Ga-SPECT/CT were: sensitivity, specificity, PPV and NPV of 67%, 93%, 97% y 48%, respectively which were slightly lower than those found for the 18F-FDG PET/CT (86%, 52%, 70% and 92%, respectively). The diagnostic yield was 73% which increased to 80% in the patients who lacked empirical treatment. CONCLUSION: Despite the better results of 18F-FDG PET/CT, 67Ga-SPECT/CT behaved as a useful technique in the management of FSUO. It is advisable to use it if 18F-FDG PET/CT is not available.

Gammagrafía de receptores de somatostatina con -DOTATATE PET/CT: experiencia inicial en Cuba / Somatostatin receptor scintigraphy with -DOTATATE PET/CT: initial experience in Cuba

En 1870 Rudolf Heidenhain descubrió las células neuroendocrinas, las cuales dan origen a los Tumores Neuroendocrinos (TNE) que son una forma rara de cáncer, la mayoría de los cuales expresan receptores de somatostatina. El fundamento de la Gammagrafía de Receptores como imagen metabólico-molecular se fundamenta en el empleo de -DOTA-péptidos con enlazamiento específico a los receptores de somatostatina. La presente publicación tiene el propósito de dar a conocer nuestras primeras experiencias en el estudio de diferentes tipos histológicos de TNE por medio de la Gammagrafía de Receptores de Somatostatina (GRS) empleando el -DOTATATE PET/CT realizados en el Centro PET/CT e incluyendo Imagen Molecular del Departamento de Medicina Nuclear del Instituto Nacional de Oncología y Radiobiología (Inor)

In 1870, Rudolf Heidenhain discovered neuroendocrine cells, which can lead to the development of the Neuroendocrine Tumors (NER), a rare form of cancer, most of which express somatostatin receptors. The basis of Receptor Scintigraphy as a metabolic-molecular image is based on the use of -DOTA-peptides with specific binding to somatostatin receptors.The purpose of this publication is to present our first experiences in the study of different histological types of TNE by means of Somatostatin Receptor Scintigraphy (GRS) using -DOTATATE performed at the PET / CT Center and Molecular Image of the Department of Nuclear Medicine of the National Institute of Oncology and Radiobiology (Inor)

SPECT/CT with radiolabeled somatostatin analogues in the evaluation of systemic granulomatous infections / SPECT/CT com análogos radiomarcados de somatostatina na avaliação de infecções granulomatosas sistêmicas

Abstract Objective: To evaluate SPECT/CT with radiolabeled somatostatin analogues (RSAs) in systemic granulomatous infections in comparison with gallium-67 (67Ga) citrate scintigraphy. Materials and Methods: We studied 28 patients with active systemic granulomatous infections, including tuberculosis, paracoccidioidomycosis, pneumocystosis, cryptococcosis, aspergillosis, leishmaniasis, infectious vasculitis, and an unspecified opportunistic infection. Of the 28 patients, 23 had started specific treatment before the study outset. All patients underwent whole-body SPECT/CT imaging: 7 after injection of 99mTc-EDDA-HYNIC-TOC, and 21 after injection of 111In-DTPA-octreotide. All patients also underwent 67Ga citrate imaging, except for one patient who died before the 67Ga was available. Results: In 20 of the 27 patients who underwent imaging with both tracers, 27 sites of active disease were detected by 67Ga citrate imaging and by SPECT/CT with an RSA. Both tracers had negative results in the other 7 patients. RSA uptake was visually lower than 67Ga uptake in 11 of the 20 patients with positive images and similar to 67Ga uptake in the other 9 patients. The only patient who did not undergo 67Ga scintigraphy underwent 99mTc-EDDA-HYNIC-TOC SPECT/CT-guided biopsy of a lung cavity with focal RSA uptake, which turned to be positive for aspergillosis. Conclusion: SPECT/CT with 99mTc-EDDA-HYNIC-TOC or 111In-DTPA-octreotide seems to be a good alternative to 67Ga citrate imaging for the evaluation of patients with systemic granulomatous disease.

Resumo Objetivo: Avaliar o estudo SPECT/CT com análogos de somatostatina radiomarcados (RSA) em infecções granulomatosas sistêmicas, em comparação com o estudo com gálio-67 (67Ga). Materiais e Métodos: Vinte e oito paciente com infecção granulomatosa sistêmica ativa foram estudados, incluindo tuberculose, paracoccidioidomicose, pneumocistose, criptococose, aspergilose, leishmaniose, vasculite infecciosa e uma infecção oportunista inespecífica. Vinte e três tinham iniciado o tratamento previamente ao estudo. Todos fizeram imagem de varredura e SPECT/CT, 7 deles pós-injeção de 99mTc-EDDA-HYNIC-TOC e os outros 21 pós-injeção de 111In-DTPA-octreotide. Todos os pacientes também fizeram cintilografia com 67Ga, exceto um, que fez biópsia guiada por 99mTc-EDDA-HYNIC-TOC. Resultados: Vinte e sete sítios de atividade foram detectados com 67Ga em 20 de 27 pacientes, também vistos nos estudos com RSA. Ambos foram negativos nos outros 7 pacientes. A captação de RSA foi visualmente menor que a de 67Ga em 11 de 20 pacientes positivos e similar nos outros 9. Um paciente que não pôde fazer cintilografia com 67Ga, fez biópsia guiada por 99mTc-EDDAHYNIC-TOC SPECT/CT em uma cavidade pulmonar com captação desse traçador, que foi positiva para aspergilose. Conclusão: SPECT/CT com 99mTc-EDDA-HYNIC-TOC ou 111In-DTPA-octreotide parece ser uma boa alternativa para o estudo com 67Ga na avaliação de pacientes com doença granulomatosa sistêmica.

Patologías benignas y variantes que captan 68Ga-DOTATATE en PET/TC / Benign Pathology And Variants With Uptake In 68ga-Dotatate Pet/Ct Studies

Objetivos: Valorar las variantes fisiológicas, anatómicas y lesiones benignas en estudios por tomografía computada por emisión de positrones (PET/TC) con Galio 68 (68Ga)-DOTATATE. Materiales y métodos: Se revisaron en forma retrospectiva los informes de PET/TC con 68Ga-DOTATATE y se seleccionaron aquellos en los cuales se mencionaran palabras en el reporte relacionadas a variantes anatómicas, fisiológicas y tumores benignos. El grado de captación del 68Ga-DOTATATE fue evaluado de forma cualitativa y cuantitativa mediante la medición del valor estandarizado de captación máximo (SUVmax). Se consignó la localización del hallazgo, el valor de SUVmax y la imagen morfológica por tomografía computada (TC). Todos los casos fueron controlados mediante evolución clínica y hallazgos imagenológicos. Resultados: De un total de 772 informes de PET/TC se obtuvo un total de 28 pacientes con 33 variantes o tumores benignos, 14 mujeres y 14 hombres con edad promedio de 63 años. Las captaciones se clasificaron en cuatro grupos: variantes anatómicas y/o fisiológicas (n = 15), dependientes de la actividad osteoblástica (n=4), dependientes de actividad inflamatoria (n = 10) y tumores benignos no neuro-endócrinos (n = 4). Discusión: Los receptores de somatostatina se localizan no sólo en el sistema neuroendócrino sino también en otros tejidos. Las variantes fisiológicas, anatómicas y tumores benignos que expresan estos receptores pueden inducir a un error diagnóstico. Conclusión: Las variantes fisiológicas y lesiones benignas (tumorales e inflamatorias) pueden captar 68Ga-DOTATATE ya que sus tejidos pueden expresar receptores de somatostatina. El análisis semiológico del componente tomográfico de este método de imágenes híbrido, permite la orientación diagnóstica, optimizando el rendimiento del estudio PET/TC.

Purpose: To evaluate the physiological, anatomical variants and benign lesions in positrón emission computed tomography (PET/CT) studies with 68Ga-DOTATATE. Materials and methods: We retrospectively reviewed PET/CT reports scanned with 68Ga-DOTATATE and selected those that contained words in the report related to anatomical, physiological variants and benign tumors. The degree of 68Ga-DOTATATE uptake was evaluated qualitatively and quantitatively by measuring the standarized uptake max value (SUVmax value). The anatomical location, SUVmax value and morphological CT image findings were recorded. All cases had clinical and imaging follow-up. Results: From a total of 772 PET/CT reports, 28 patients were obtained with 33 benign variants or tumors, 14 females and 14 males with a median age of 63 years. Uptake patterns were classified into four groups: anatomic and physiological variants (15), dependent on osteoblastic activity (4), dependent on inflammatory activity (10) and non-neuro-endocrine benign tumors (4). Discussion: Somatostatin receptors are overexpressed not only in the neuroendocrine system but also in other tissues. Physiological, anatomical variants and benign tumors expressing these receptors may be misleading. In the present work the frequency of this finding is 5.1%. Conclusion: Physiological variants and benign lesions (tumor and inflammatory) can accumulate 68Ga-DOTATATE since their tissues can express somatostatin receptors. The semiologic analysis of the tomographic component of this hybrid method enhances the diagnostic efficacy, optimizing PET/CT study performance.

Uso de solventes no acuosos en la síntesis del radioconjugado DOTA-1-Nal3-octreotida marcado con galio-68 / Use of non-aqueous solvents in the synthesis of radioconjugate DOTA-1-Nal3-octreotide labeled with gallium-68

Los tumores neuroendocrinos sobreexpresan receptores de somatostatina. Su diagnóstico se ha extendido debido al radiomarcaje de DOTA-péptidos como el análogo de somatostatina DOTA-1--octreotida (DOTA-NOC) conjugado con radionúclidos emisores ß+ como el , de propiedades físico-nucleares muy favorables. El presente trabajo describe los procedimientos para el radiomarcaje del DOTA-NOC con , en medio acuoso puro y en presencia de solventes no acuosos, así como los métodos usados para el control de calidad, donde se obtuvo una formulación con un rendimiento radioquímico superior al 95 %. La adición de etanol (30%- vol/vol) a la mezcla de reacción permitió incrementar la actividad específica del radioconjugado -DOTA-NOC, y se alcanzó un valor de 182 MBq/nmol, superior al reportado en la literatura (50 MBq/nmol) para el marcaje en medio acuoso puro. También se presentan los estudios de estabilidad (en presencia de solución salina y tampón fosfato salino), estudios de transmetalación en soluciones de , , y , competencia por retos contra los quelatos EDTA y DTPA y estabilidad in vitro en transferrina humana, realizados al radioconjugado -DOTA-NOC, del cual se mostró su elevada estabilidad (> 95 %). En comparación con el medio acuoso puro, el uso de solventes no acuosos en la síntesis del radioconjugado DOTA-1--octreotida marcado con galio-68, permite disminuir la masa de conjugado y los tiempos de reacción, incrementar significativamente los rendimientos y la actividad específica del compuesto marcado. Ello pudiera favorecer la obtención del producto con mejores características en sistemas modulares que se encuentran en fase de desarrollo.

Neuroendocrine tumors specifically over-express somatostatin receptors. Their diagnosis has expanded due to radiolabelling of DOTA-peptides such as somatostatin analogue DOTA-1--Octreotide (DOTA-NOC) conjugated to ß+ emitting radionuclides such as , with very favorable decay-properties. This paper describes the radiolabeling procedures of DOTA-NOC with , in a pure aqueous medium and in presence of non-aqueous solvents as well as the methods used for quality control where a formulation is obtained with a radiochemical yield exceeding 95%. Adding ethanol (30 % - v / v) to the reaction mixture allowed increasing the specific activity of -DOTA-NOC radioconjugated, reaching a value of 182 MBq / nmol, higher than reported in literature (50 MBq / nmol) for labeling in a pure aqueous medium. Stability studies are also presented (in presence of saline solution and saline phosphate buffer, transmetallation studies in , , and solutions, challenges competition against EDTA and DTPA chelators and in vitro stability in human transferrin) performed to -DOTA-NOC radioconjugated, showing its high stability (> 95 %). Compared with the aqueous medium, the use of non aqueous solvents in the synthesis of radioconjugate DOTA-1--octreotide labeled with gallium-68, helps reduce the mass of conjugate and the reaction time, significantly increase yields and specific activity of the labeled compound. This could facilitate obtaining the product with better characteristics in modular systems that are under development.

PET-CT: tumores de cabeza y cuello. Ensayo pictórico y revisión de la literatura / PET-CT: Head and Neck Tumors. Picture essay and literature review

La PET-CT como modalidad diagnóstica es muy útil en la evaluación anatomofisiológica de la cabeza y el cuello. Proporciona una alta sensibilidad y especificidad en la estadificación de neoplasias primarias, la respuesta al tratamiento médico o quirúrgico y la detección de recurrencias. Dichas enfermedades representan un alto impacto sobre la mortalidad y morbilidad de los pacientes. El principal objetivo de esta publicación es hacer una revisión de los hallazgos en la PET-CT de los tumores más frecuentes de cabeza y cuello, con énfasis en los procesos malignos, estudiados en nuestra institución.

PET-CT as a diagnostic modality which is very useful in the anatomical-physiological assessment of the head and neck. It provides high sensitivity and specificity in the staging of primary tumors, the response to medical or surgical treatment and the detection of recurrences. These diseases represent a high impact on the mortality and morbidity in our patients. Our main objective is to review the findings on PET-CT of the most common head and neck tumors with an emphasis on malignancy which are studied in our institution.

Radiofármacos de galio 68 / Gallium radiopharmaceuticals 68

La tomografía de emisión de positrones (PET) es una técnica de imagen médica de gran sensibilidad y resolución, que requiere radionúclidos emisores de positrones de corta vida. Los más comúnmente usados son el 18F y el 11C. La principal dificultad de estos radionúclidos es la necesidad de instalar un ciclotrón en el sitio de uso o a distancias no muy grandes de este, por lo que se han investigado radionúclidos más convenientes como el 68Ga. Su disponibilidad a partir de los sistemas generadores de larga vida ? / 68Ga, de los que se obtiene Ga3+, utilizable durante tiempo un prolongado en sitios alejados del ciclotrón y la rica química de coordinación del 68Ga+, han posibilitado la incorporación a la práctica médica de algunos radiofármacos, así como la investigación de una variedad de complejos estables de Ga3+ acoplados ...

PET (positron emission tomography) is a technique of medical image of great sensibility and high resolution that requires short-lived positron emitting radionuclides. The most commonly used are 18F and 11C.The main difficulty of these radionuclides is the necessity to install a cyclotron in the site of use or not very far from it. Therefore convenient radionuclides have been researches, among them 68Ga. The availability of this radionuclide from long-lived ? / 68Ga generators, which can been used for along time far from the cyclotron location, and the rich coordination chemistry of 68Ga have allowed to incorporate to the medical practice some radiopharmaceuticals as well as the research of a variety of stables complexes of Ga3+ coupled to biomolecules for diagnostic imaging of cancer and cardiovascular and neurological diseases. The present work is aimed at examining the potentialities of the...

Utilidad del citrato de galio 67 en el diagnóstico de fiebre de origen desconocido / Effectiveness of gallium 67 citrate in diagnosing fever of unkown origin

Se presenta el caso de un paciente con cuadro de 4 meses de evolución de fiebre intermitente, pérdida no cuantificada de peso y diaforesis nocturna. El examen físico reveló hepatoesplenomegalia sin otras alteraciones. Los estudios iniciales mostraron anemia macrocítica-hipocrómica, y las serologías para VIH, hepatitis B y hepatitis C fueron negativas. La TAC de cuello reportó adenomegalias cervicales subcutáneas bilaterales; a una de ellas se le tomó una biopsia, que resultó negativa para malignidad o infección. El objetivo de este reporte es ilustrar la utilidad del 67Gacitrato en el estudio de la fiebre de origen desconocido.

Presentation is made of the case of a patient with a 4-month history of intermittent fever, unquantified weight loss and night sweating. Physical examination revealed heptosplenomegaly, with no additional alterations. Initial studies showed macrocytic-hypochromic anemia; serology tests for HIV, hepatitis B, and hepatitis C were negative. CT of the neck reported bilateral subcutaneous cervical lymphadenopathy; biopsy was performed on one, which resulted negative for malignancy or infection. The purpose of this report is to illustrate the effectiveness of Ga-citrate 67 in the study of fever of unknown origin.

Oral steroid therapy for frozen shoulder / Terapia de esteroides orales para el hombro congelado

BACKGROUND: Since frozen shoulder is characterized by spontaneous recovery, no precise treatment strategy exists. Both conservative therapy and arthroscopic surgery is available, but the time required for recovery varies considerably. This study looks at the possible early symptom relief with oral steroid therapy. SUBJECTS AND METHODS: The subjects were 76 patients aged 33 to 73 years at the beginning of the study. The duration of the frozen shoulder was one to 15 months (mean 5.7 months) and hypertension was noted in 13 patients as a complicated disorder. A single course of steroid therapy consisted of a total dose of 105 mg of prednisolone over approximately a three-week period by the dose-tapering method. The number of courses varied with the degree of symptom relief, but the rest period between courses was always approximately four weeks. The results were assessed on the basis of the Japanese Orthopaedic Association (JOA) score, but the principal evaluations were pain and range of motion. RESULTS: The average ranges of motion before treatment were 102.8º of forward flexion 11.3º of external rotation and internal, rotation was at the buttocks. However, after one course of treatment, forward flexion was 136º, external rotation was 33.7º, and internal rotation was limited to the buttocks in only six cases. CONCLUSION: The results of oral steroid therapy for frozen shoulder were highly satisfactory. However, sufficient care is required in explaining the method of administration and the adverse effects such as the osteonecrosis of the femoral head or osteoporosis.

ANTECEDENTES: Como que el hombro congelado se caracteriza por la recuperación espontánea, no existe una estrategia de tratamiento precisa. Tanto la terapia conservadora como la cirugía artroscópica se hallan a disposición, pero el tiempo requerido para la recuperación varía considerablemente. Este estudio echa una ojeada al posible alivio de los síntomas tempranos por medio de la terapia de esteroides orales. SUJETOS Y MÉTODO: Los sujetos fueron 76pacientes en edades de 33 a 73 años al comienzo del estudio. La duración del hombro congelado fue de 1 a 15 meses (promedio 5.7 meses), y se observó hipertensión en 13 pacientes como una condición co-mórbida. Un solo tratamiento con esteroides consistía en una dosis total de 105 mg de prednisolona por un período de aproximadamente tres semanas mediante el método de reducción gradual de la dosis. El número de tratamientos varió de acuerdo con el grado de alivio del síntoma, pero el período de descanso entre tratamientos fue aproximadamente de cuatro semanas. Los resultados fueron evaluados sobre la base de la puntuación establecida por la Asociación Ortopédica del Japón (JOA), y las evaluaciones principales fueron el dolor y el alcance del movimiento. RESULTADOS: El rango promedio del movimiento antes del tratamiento fue 102.8º deflexión delantera, y 11.3º de rotación externa y la rotación interna fue en las nalgas. Sin embargo, luego de un tratamiento, la flexión delantera fue 136º, la rotación externa fue 33.7º, y la rotación interna estuvo limitada a las nalgas en sólo seis casos. CONCLUSIÓN: Los resultados de la terapia de esteroides orales para el hombro congelado, fueron altamente satisfactorias. Sin embargo, se requiere suficiente cuidado al explicar el método de administración y los efectos adversos, tales como la osteonecrosis de la cabeza del fémur o la osteoporosis.

Influência do laser arseneto de gálio-alumínio em feridas cutâneas de ratos / Influence of gallium-aluminum arsenide laser in the cutaneous wounds in wistar rats

Objetivo: O presente estudo avaliou o efeito do laser arseneto de gálio-alumínio (GaAsAl) 830nm(30j/cm²) e da pomada Dersani® no processo cicatricial cutâneo de ratos wistar, em relação à proliferação fibroblástica e revascularização. Material e métodos: Foram utilizados 18 ratos wistar adultos jovens, machos, com peso médio de 324 g, provenientes do Biotério do Centro de Ciências Biológicas da Universidade Federal de Viçosa. Foram feitas cinco feridas de 12 mm no dorso dos animais utilizando bisturi. Os animais foram divididos aleatoriamente em três grupos, cada grupo com seis animais: Grupo 1: Controle - os animais tiveram a ferida tratada com salina, Grupo 2:Feridas tratados com laser GaAsAl (830nm) 30J/cm² e Grupo 3: Feridas tratadas com Dersani®. As aplicações foram feitas diariamente durante 20 dias de experimento. O material para análise histológica foi corado com hematoxilina-eosina (HE), fotografados e analisados por meio do programa Image Pro-plus®, por contagem de pontos sob células de interesse. Resultados: Foi observado maior número de fibroblastos nos grupos tratados com o laser GaAsAl e com a pomada Dersani®, quando comparados ao controle no quarto dia do experimento. No entanto, no oitavo dia o grupo tratado com laser apresentou um número significativamente menor de fibroblastos, quando comparado ao controle e ao Dersani®. Em relação à revascularização foi observada diferença significativa entre o laser e o Dersani® no oitavo dia de experimento, em que o Dersani® se mostrou mais efetivo na formação de vasos sanguíneos. Conclusão: O grupo tratado com o laser GaAsAl no quarto dia aumentou significativamente a quantidade de fibroblastos quando comparado ao controle.

Objective: The present work evaluates the effect of the gallium-aluminum arsenide (GaAsAl) (30j/cm²) laser and ointment DersaniTM, on the cutaneous cicatricial process the wistar rats, in respect of fibroblast proliferation and revascularization. Materials and methods: The study made use of 18 wistar rats, young adults, males, with medium weight of 324 g, from the animal house of Centro de Ciências Biológicas e da Saúde (Health and Biological Sciences Center) of Universidade Federal de Viçosa, MG, Brazil. Five 12 mm wounds were made in the dorsal region of the rats using scalpel blades. Animals were separated in 3 groups, each one with six animals. Group 1: Control - Animals had the wound treated with saline; Group 2: Wound treated with GaAsAl (30J/cm²) laser; and Group 3: wound treated with DersaniTM. The applications were made daily during 20 days of experiment. The material for histological analyses was stained with hematoxilin-eosin (HE), photographed and analyzed using the program Image Pro-plusTM through enumeration of points under the cells of interest. Results: It was observed an increase in the number of fibroblasts in the groups treated with GaAsAl 30J/cm² and with DersaniTM ointment when compared to controls in the fourth day of experiment. However, in the eighth day the group treated with laser presented a significant reduced number of fibroblasts when compared to control and DersaniTM groups. In relation to revascularization, significant differences between laser and DersaniTM were observed in the eighth day of the experiment, where to DersaniTM showed to be more effective in the formation of blood vessels. Conclusion: The group GaAsAl laser on the fourth day, there was a significantly greater quantity of fibroblasts compared to control group.

Importância da cintilografia com gálio-67 no linfoma cutâneo primário de células B: relato de dois casos / Importance of gallium-67 scintigraphy in primary cutaneous B-cell lymphoma: report of two cases

Os autores relatam dois casos de linfoma cutâneo de células B, nos quais o correto estadiamento, tratamento e seguimento foram possíveis graças à combinação de exames convencionais e a cintilografia com gálio-67.

The authors describe two cases of cutaneous B-cell lymphoma where correct staging, treatment and follow-up could be achieved through a combination of conventional imaging studies and gallium-67 scintigraphy.

Radionuclide imaging of infection: what the future holds

Nuclear Medicine plays an important role in the evaluation of patients suspected of harboring infection. Gallium imaging is especially useful for opportunistic infections and spinal osteomyelitis. In vitro labeled leukocyte imaging is the current radionuclide gold standard for imaging most infections, in immunocompetent patients, including cardiovascular, postoperative, and musculoskeletal infections (except spinal osteomyelitis). Several in-vivo leukocyte labeling methods have been investigated, but none are widely used. Results obtained with radiolabeled antibiotics have been disappointing. Data on FDG are still emerging, but this agent appears to be especially valuable in fever of unknown origin, spinal osteomyelitis, vasculitis and sarcoidosis. It is conceivable that in the near future, FDG-PET and PET/CT will replace gallium for many indications. Investigators also are studying ways to label leukocytes with positron emitters in order to combine the advantages of PET with those of labeled leukocytes.

Medicina Nuclear tem um importante papel na avaliação de pacientes suspeitos de apresentar infecção. A imagem obtida com gálio é especialmente útil para infecções oportunistas e osteomielite espinal. Imagem de leucócitos marcados in vitro com radionuclídeo é o padrão ouro atual para imagem de muitas infecções, em pacientes imunocompetentes, incluindo os cardiovasculares, pós-cirúrgicos, e com infecções músculo-esqueléticas (exceto osteomielite espinal). Vários métodos de marcação de leucócitos in vivo têm sido investigados, mas nenhum é amplamente utilizado. Resultados obtidos com antibióticos radiomarcados têm sido decepcionantes. Os dados sobre FDG são ainda emergentes, mas esse agente parece ser especialmente valioso em febre de origem desconhecida, osteomielite espinal, vasculite e sarcoidose. É concebível que em futuro próximo, FDG-PET e PET/CT irão substituir o gálio para imagem de infecção e inflamação. Investigadores estão estudando modos de marcar leucócitos com emissores de pósitron para combinar as vantagens do PET com aquelas dos leucócitos marcados.

O gálio e a patologia óssea / Gallium and bone pathology

PROPOSTA: Revisão de trabalhos científicos referentes à incorporação do gálio no tecido ósseo, ao mecanismo da atividade terapêutica desse elemento, bem como a formação, crescimento e solubilidade da hidroxiapatita na presença dos sais de gálio. JUSTIFICATIVA: Diferente de outras drogas que impedem a perda de cálcio, os sais de elemento traço gálio são eficazes em hipercalcemia severa. O gálio (geralmente na forma de nitrato) aumenta a concentração de cálcio e fósforo no osso, influindo nos osteoclastos de maneira direta não tóxica, em doses surpreendentemente baixas. Apesar de que os detalhes do mecanismo de ação do gálio não são bem esclarecidos, está comprovado que esse mecanismo envolve a inserção do gálio na matriz de hidroxiapatita, protegendo-a contra a reabsorção e melhorando as propriedades biomecânicas do sistema esquelético. Este fármaco age também nos componentes celulares do osso, impedindo sua absorção ao diminuir a secreção ácida dos osteoclastos. São necessárias mais publicações sobre o uso do gálio no tratamento de várias doenças onde prevalece esta patologia. CONCLUSÕES: Devido as suas características interessantes e promissoras, o gálio merece ser futuramente avaliado do ponto de vista experimental e clínico, como um agente antiabsortivo em ortopedia, traumatologia e doenças relacionadas com o câncer. Maior conhecimento dos mecanismos envolvidos pode fornecer as idéias para estratégia terapêutica, com o objetivo de diminuir hipercalcemia e perda óssea. Espera-se que novos compostos do gálio sejam desenvolvidos e avaliados clinicamente.

PURPOSE: To review the literature concerning the incorporation of gallium into bone tissue, mechanisms of therapeutic activity of this element, as well as the formation, growth and solubility of hydroxiapatite in the presence of gallium salts. JUSTIFICATION: In contrast to other calcium-saving drugs, salts of trace element gallium are effective in severe hypercalcemias. Gallium (most commonly in the form of its nitrate) enhances calcium and phosphorus content of the bone and has direct, noncytotoxic effects on osteoclasts at markedly low doses. Although the details of gallium action on the bone are still uncertain, it is well established that the mechanism involves gallium insertion into the hydroxiapatite matrix protecting it from resorbtion and improving biomechanical properties of the skeletal system. The drug also acts on the cellular components of bone to reduce bone resorbtion by decreasing acid secretion by osteoclasts. More has to be published about the use of gallium in managing a series of clinical conditions in which this pathology is pronounced. CONCLUSIONS: Due to its interesting and promising profile gallium merits further experimental and clinical evaluation as an antiresorbtive agent in orthopaedics, traumatology and cancer-related conditions. Greater knowledge of the mechanisms involved may provide insights for therapeutic strategies aimed at diminishing hypercalcemy and bone loss. New gallium compounds are expected to be developed and tested clinically.