PET/CT with 18F-Fluordesoxyglucose in patients with suspected endovascular prosthesis infection. / PET/TC con 18F-Fluordesoxiglucosa en pacientes con sospecha de infección de prótesis endovasculares.

OBJECTIVE: Infection of large vessel prostheses is a rare but critical complication. The aim of this work is to assess the impact of PET/CT with 18F-Fluordesoxyglucose (PET-FDG) on the diagnosis of infection in our environment. MATERIAL AND METHODS: Thirty-five patients (38 scans) were evaluated for suspected prosthetic infection. A qualitative analysis was performed taking into account the distribution of the radiopharmaceutical, categorizing the studies as positive or negative for infection. Those with focal or multifocal deposits along the vascular prosthesis were considered positive, and negative if a homogeneous and diffuse distribution over the whole prosthesis was observed, or a total absence of uptake. A semi-quantitative analysis was performed using SUVmax and average SUV values, and a metabolic index was calculated (SUVmax of the graft / average SUV of the normal vascular pool). RESULTS: The PET-FDG study was positive in 20 patients, with a diagnostic accuracy of 84%. The 38 PET-FDG scans performed showed positive capture patterns (focal in 6, multifocal in 15, diffuse in 4) and negative pattern in the remaining 13. The sensitivity, specificity, positive and negative predictive values obtained for the PET-FDG were 95%, 89%, 90% and 94%, and for the AngioTC study 50%, 73%, 73% and 50%, respectively. The area values under the ROC curve were as follows: for the AngioTC 0.642 (not significant), and for the SUVmax values of 0.925 (p<0.005), average SUV of 0.922 (p<0.005) and for the metabolic index of 0.917 (p<0.005). CONCLUSIONS: The PET-FDG proves to be a tool with high diagnostic accuracy in the infection of vascular prosthesis, both visual analysis according to patterns and semi-quantitative.

The downfall of the linear non-threshold model. / El ocaso del modelo lineal sin umbral.

The linear non-threshold model (LNTM) is a theoretical dose-response function as a result of extrapolating the late effects of high-dose exposure to ionizing radiation to the low-dose range, but there is great uncertainty about its validity. The acceptance of LNTM as the dominant probabilistic model have survived to the present day and it is actually the cornerstone of current radiation protection policies. In the last decades, advances in molecular and evolutive biology, cancer immunology, and many epidemiological and animal studies have cast serious doubts about the reliability of the NLTM, as well as suggesting alternative models, like the hormetic theory. Considering the given evidences, a discussion between the involved scientific societies and the regulatory commissions is promtly required in order to to reach a redefiniton of theradiation protection basis, as it would be specially crucial in the medical field.

Resultados de la biopsia selectiva de ganglio centinela combinada con la localización radioguiada de tumores invasivos no palpables de mama. Técnica de SNOLL / No disponible

Objetivo: La biopsia selectiva del ganglio centinela mediante inyección intralesional de un radiocoloide, combinado con la localización radioguiada de tumores no palpables de mama en el mismo acto quirúrgico se denomina técnica de SNOLL. El objetivo de nuestro estudio es mostrar la factibilidad y sencillez para realizar la técnica en un hospital provincial de 2º nivel dotado con Servicio de Medicina Nuclear, comparando nuestros resultados con las publicaciones de referencia. Métodos: Entre enero 2007 y marzo 2008 se incluyeron 20 pacientes consecutivas diagnosticadas de carcinoma no palpable de mama. Se realizó inyección intratumoral de un nanocoloide- Tc99 de albúmina (0,2 ml, 37MBq) guiada por ecografía o estereotaxia seguida de linfogammagrafía e instilación subareolar de colorante azul patente (2 ml). Tras identificación del ganglio centinela se detectó y extirpó la lesión mamaria mediante uso de sonda detectora de rayos gamma. Se verificaron radiológicamente todos los especímenes extirpados. Resultados: Se obtuvo al menos un ganglio centinela mediante marcaje radiactivo en 19 pacientes (95%). En un paciente el ganglio centinela se detectó únicamente mediante colorante. La localización radioguiada y extirpación de la lesión primaria se consiguió en todos los casos. En dos casos (10%), los márgenes se encontraban afectos (< 2 mm) por enfermedad in situ extensa asociada. 4 pacientes presentaron ganglio centinela positivo. Conclusiones: Las conclusiones de nuestra serie se encuadran en las publicadas hasta la fecha, otorgando a la técnica de SNOLL mejores resultados que la localización con guía metálica y confirmando la factibilidad de la misma en cualquier centro con recurso a Medicina Nuclear(AU)

Introduction: The SNOLL technique results of the combination of radioguided occult lesion localization (ROLL) and sentinel node mapping with a single radiotracer injection in the management of non-palpable breast cancer. The aim of this study was to evaluate the feasibility of this technique in a second-level hospital with a nuclear medicine department and compare our results with the reference publications. Methods: From January 2007 to March 2008, lymphoscintigraphy was performed in 20 consecutive patients with non-palpable breast cancer after the intratumoral injection of albumin nanocolloid-Tc99 (0.2 ml, 37 MBq) guided by stereotaxis or ultrasound. Under general anaesthesia, a subareolar injection of blue dye was performed. After sentinel lymph node biopsy, the gamma-ray detection probe was used for radioguided removal of the breast tumor. All the breast lesions were identified on X-ray control of the surgical specimen. Results: Al least one sentinel node was removed in 19 patients (95%). In one patient, the sentinel node was only detected by blue dye. Radioguided surgery of the breast tumor was successfully achieved in all patients. In two cases (10%), in situ carcinoma was present close to the margins of the surgical specimen (< 2 mm) and further re-excision was therefore performed. Axillary dissection was accomplished in 4 patients with sentinel node metastases. Conclusions: The findings of our study are consistent with those published to date, showing the advantage of SNOLL technique over the wire-guided localization of non-palpable breast cancer and confirming its feasibility in any center with a reference nuclear medicine department(AU)

Tomografía por emisión de positrones (PET): indicaciones en oncología / Positron Emission Tomography (PET): indications in oncology

La Tomografía por Emisión de Positrones con 18F-Fluorodeoxiglucosa (PET-FDG) es una técnica de diagnóstico por imagen cuyo uso se ha generalizado en España durante la última década. Para optimizar la utilización de esta tecnología es necesario ajustarse a una serie de indicaciones concretas, en las cuales la PET-FDG ha demostrado sobradamente su superioridad con respecto a los métodos convencionales de diagnóstico. Dichas indicaciones incluyen: la estadificación de tumores pulmonares y linfomas; la reestadificiación de tumores de tiroides, colorrectales, de cabeza-cuelli, linfomas y melanomas; la localización de tumores de origen desconocido; la caracterización del nódulo pulmonar solitario; y por último, el diagnóstico diferencial recidiva/radionecrosis en tumores cerebrales (AU)

This work details the Positron Emission Tomography technique with 18F-Fluorodeoxiglucose (PET-FDG), the use of which is becoming more generalized in our country. It also explains that in order to optimize the use of this technology, it is necessary to meet a series of specific indications, where its superiority has been demonstrated with respect to conventional diagnostic methods (AU)

Detección de recidiva pleuropulmonar en carcinoma de mama / Detection of pleuropulmonary relapse in breast cancer

No disponible

[Positron emission tomography (PET) imaging in head and neck cancer]. / La Tomografía por Emisión de Positrones (PET) en la patología oncológica de cabeza y cuello.

Positron Emission Tomography (PET) with 18F-Fluordeoxyglucose is a diagnostic imaging technique very useful in the management of head and neck cancer, better than anatomic imaging in most cases. PET shows higher diagnostic accuracy in the detection of local and regional tumor recurrences. PET is also indicated for the identification of unknown primary tumors when regional nodal metastasis is the presenting feature. The improved planning of radiation therapy with hybrid cameras PET-CT, the earlier diagnosis of post-radiotherapy residual disease and the possibility of monitoring the effects of chemotherapy makes PET imaging an important tool in evaluating tumor response to treatment.

La Tomografía por Emisión de Positrones (PET) en la práctica clínica oncológica / Positron emission tomography (PET) in oncological clinical practice

La Tomografía por Emisión de Positrones con 18F-fluorodeoxiglucosa (PET-FDG) es una técnica de diagnóstico por imagen cuyo uso se ha generalizado en España durante la última década. Existen una serie de indicaciones concretas, en las cuales la PET-FDG ha demostrado sobradamente su superioridad con respecto a los métodos convencionales de diagnóstico. Es recomendable, por ello, realizar un estudio PET-FDG únicamente en las siguientes situaciones: la estadificación de tumores pulmonares y linfomas, la re-estadificación de tumores de tiroides, colorrectales, de cabeza-cuello, linfomas y melanomas; la localización de tumores de origen desconocido; la caracterización del nódulo pulmonar solitario; y, por último, el diagnóstico diferencial recidiva/radionecrosis en tumores cerebrales (AU)