18F-DCFPyL PET/CT guidelines.

The objective of this guide is to provide to nuclear medicine physicians a tool based on scientific evidence and prepared by consensus of experts, to perform the 18F-DCFPyL PET/CT procedure with safely and efficiently for patients with prostate cancer who present PSMA overexpression. For them, some recommendations will be established for 18F-DCFPyL PET/CT examination: reconstruction parameters, presentation of the images and their interpretation. The possible false positives of the procedure will be analysed, how to interpret them and how to avoid them. Finally, all exploration should lead to the preparation of a report that answers the clinician's question. For this, it is recommended to prepare a structured report that includes the PROMISE criteria as well as the classification of the findings according to PSMA-RADS parameters.

Radium-223 in the treatment of bone metastasis in patients with castration-resistant prostate cancer. Review and procedure. / Radio-223 en el tratamiento de metástasis óseas en pacientes con cáncer de próstata resistente a la castración. Revisión de la literatura y procedimiento.

Bone metastatic disease is the main cause of morbidity / mortality in patients with prostate cancer, presenting frequently as bone pain, pathological fractures or spinal cord compression, which requires early and timely therapy. Although, for the moment, the therapeutic window for its use has not been definitively established, radium-223 (223Ra), an alpha particle emitter, has proved to be an effective therapeutic tool, pre or post-chemotherapy, in patients with castration-resistant prostate cancer with symptomatic bone metastases and absence of visceral metastases, significantly modifying the prognosis of the disease. It is therefore imperative to define the ideal scenarios and the correct protocol for the use of this therapy and thus offer the greatest possible clinical benefit to the patient.

68Ga-PSMA PET/CT in prostate cancer. / La PET/TC con 68Ga-PSMA en el cáncer de próstata.

Positron emission tomography/computed tomography (PET/CT) with 68Ga-PSMA is a non-invasive diagnostic technique to image prostate cancer with increased prostate-specific membrane antigen (PSMA) expression. PSMA is a transmembrane protein present in all prostatic tissues. Increased PSMA expression is seen in several malignancies, although prostate cancer is the tumour where it presents higher concentrations. Almost all prostate adenocarcinomas show PSMA expression in most of lesions, primary and metastatic. Immunohistochemistry has demonstrated that the expression of PSMA increases in patients with de-differentiated, metastatic or hormone-refractory tumours. Moreover, the expression level of PSMA has a prognostic value for disease outcome. PET measures the three-dimensional distribution of 68Ga-PSMA, producing semi-quantitative images that allow for non-invasive assessment of PSMA expression.

Optimisation of metabolic criteria in the prognostic assessment in patients with lymphoma. A multicentre study. / Optimización de los criterios metabólicos en la valoración pronóstica de los pacientes con linfoma. Estudio multicéntrico.

OBJECTIVE: To compare sensitivity, specificity and predictive value of Deauville score (DS) vs. ΔSUVmax in interim-treatment PET (iPET) and end-treatment PET (ePET), in patients with diffuse large B cell lymphoma (DLBCL), Hodgkin lymphoma (HL), and follicular lymphoma (FL). METHOD: Retrospective longitudinal multicentre study including 138 patients (46 DLBCL, 46 HL, 46 FL), on whom 3 18F-FDG PET/CT were performed: baseline, iPET, and ePET. Visual (DS) and semi-quantitative (ΔSUVmax) parameters were determined for iPET and ePET. Predictive value was determined in relation to disease-free interval. RESULTS: Statistical analysis. iPET for DLBCL, HL, and FL: 1) sensitivity of DS: 76.92/83.33/61.53%; specificity: 78.78/85/81.81%; 2) sensitivity of ΔSUVmax: 53.84/83.33/61.53%; specificity: 87.87/87.50/78.78%. ePET for DLBCL, HL and FL: 1) sensitivity of DS: 61.53/83.33/69.23%; specificity: 90.90/85/87.87%; 2) sensitivity of ΔSUVmax: 69.23/83.33/69.23%; specificity: 90.90/87.50/84.84%. Predictive assessment. iPET study: in DLBCL, DS resulted in 10.3% recurrence of negative iPET, and 17.1% in ΔSUVmax at disease-free interval; in HL, both parameters showed a 2.8% recurrence of negative iPET; in FL, DS resulted in 15.6% recurrence of negative iPET, and 16.1% in ΔSUVmax, with no statistical significance. ePET study: in DLBCL, DS resulted in 14.3% recurrence of negative ePET, and 11.8% in ΔSUVmax at disease-free interval; in HL and FL, both methods showed 2.8 and 12.5% recurrence in negative ePET, respectively. CONCLUSION: DS and ΔSUVmax did not show significant differences in DLBCL, HL and FL. Their predictive value also did not show significant differences in HL and FL. In DLBCL, DS was higher in iPET, and ΔSUVmax in ePET.

A False-Negative Case of Primary Central Nervous System Lymphoma on 11C-Methionine PET and Intense 18F-FDG Uptake.

We report a case of a 44-year-old man with neurological symptoms and MRI findings, which were unable to differentiate between glioma and lymphoma. Metabolic characterization by means of PET imaging with F-FDG and C-methionine is proposed to determine the benign or tumor (high- and low-grade) origin of brain lesions. In this case, the MRI lesion corresponded with an inconclusive metabolic pattern of intense F-FDG uptake and no significant C-methionine uptake. Pathological study revealed a false-negative case of C-methionine due to lymphoma.

Metastatic Renal Cell Cancer Treated With Antiangiogenic Therapy Monitoring by 18F-FDG PET/CT.

Renal cell carcinoma (RCC) is resistant to chemotherapy and radiotherapy in most cases, and surgery is the preferred option in patients with local tough advanced disease. Even in metastatic RCC, patient survival has been reported to improve after surgery. Considering the importance of angiogenesis in RCC pathogenesis, new inhibitors of vascular endothelial growth factor pathway show promising results. Imaging monitoring with F-FDG PET/CT may allow selecting the appropriateness and right time to implement these drugs, according to disease outcome.

Therapeutic Algorithm Guided by Sequential 11C-Choline PET/CT in a Patient With Metastatic Castration-Resistant Prostate Cancer.

Antiandrogen therapy alone or combined with radical therapy is the first choice in diagnosis and recurrence of patients with metastatic prostate cancer. However, patients on androgen deprivation frequently show treatment resistance. In recent years, new treatments for metastatic castration-resistant prostate cancer have been developed. Clinical studies with docetaxel have shown its usefulness for first-line therapy, and different therapeutic algorithms with second-line drugs like abiraterone or cabazitaxel have also been proposed. Sequential metabolic study with PET/CT imaging with ¹¹C-choline may be important for assessing the right moment for administration each one of the therapeutic options.

Patterns of extension of gastrointestinal stromal tumors (GIST) treated with imatinib (Gleevec®) by 18F-FDG PET/CT.

BACKGROUND AND AIM: currently it is recognized the usefulness of 18F-FDG PET in assessing response to therapy with imatinib (Gleevec®) in the gastrointestinal tract sarcomas (GIST). To facilitate the follow-up of these studies is important to know the patterns of metastatic spread. The aim of this paper is to describe patterns observed in the 18F-FDG PET/CT. METHOD: retrospective study included 29 patients who underwent 18F-FDG PET/CT after being diagnosed with unresectable or metastatic GIST. In total, 87 PET/CT studies were performed (1-6 controls per patient) with a mean time of follow-up 6-36 months. We analyzed the location of the lesions evidenced in PET, CT and fusion. Images were evaluated visually and semiquantitatively (SUV). In cases in which has been considered necessary, additional images have been undertaken: PET delayed imaging, intravenous contrast CT and inspiratory chest CT. RESULTS: the most common primary site was the stomach (41%), small bowel (35%), and rectum (24%). Significant changes in the location of metastatic disease between pre-treatment and the monitoring were observed, with the appearance of more extra-abdominal disease. CONCLUSIONS: individualization of protocol studies and interpretation of PET, CT and fused images were required for evaluation of treatment response to imatinib. Hybrid 18F-FDG PET/CT provides an accurate determination of the extent of GIST. While the most common metastatic site is the liver and peritoneum, in the following cases are common extra-abdominal disease.

[Utility of inspiratory diagnostic CT scan after CT/PET study in the detection of pulmonary nodules]. / Utilidad de la TC diagnóstica inspiratoria tras la realización del estudio PET/TC en la detección de nódulos pulmonares.

We present the case of a 57-year old woman diagnosed of papillary thyroid carcinoma and treated with thyroidectomy followed by radioiodine (I-131) on two occasions. Follow-up radioiodine scan showed disease in right cervical region, confirmed by fine needle aspiration (FNA) and treated with lymphadenectomy. Due to thyroglobulin elevation, I-131 scan negative and inconclusive cervical ultrasonography/CT scan, we conducted a CT/PET study that confirmed cervical disease. An additional CT scan that was performed on maximum-inspiration showed four micro-nodules, one of which was not detected by the CT scan on shallow breathing (CT/PET). Post-treatment (I-131) scan confirmed uptake in these localizations. Good fusion between PET and CT images that avoids the errors of attenuation correction, especially in the lung bases, is necessary for correct image interpretation of the CT/PET study. Shallow breathing is necessary in order to obtain optimal image fusion with the CT/PET study, although this is not the best to evaluate pulmonary parenchyma in which an additional inspiratory CT scan improves detection of the pulmonary nodules.

Utilidad de la TC diagnóstica inspiratoria tras la realización del estudio PET/TC en la detección de nódulos pulmonares / Presentamos el caso de una mujer de 57 años diagnosticada de carcinoma papilar de tiroides, tratada con tiroidectomía y radioyodo en dos ocasiones. Un rastreo de control muestra captación cervical derecha, confirmada por punción aspiración con aguja fina, tratada con linfadenectomía. Ante la elevación de tiroglobulina, el rastreo negativo y la ecografía/TC cervical inespecífica se realiza un estudio tomográfico por emisión de positrones/tomográfico computarizado (PET/TC) que confirma infiltración del lecho cervical. Adicionalmente se le realiza una TC en máxima inspiración que muestra cuatro micronódulos, uno de ellos no detectado por la TC del estudio PET/TC. El rastreo posterapéutico (I-131) confirma captación en estas localizaciones. Para la correcta interpretación de las imágenes PET/TC se necesita una fusión óptima de la PET y la TC, que minimice errores de corrección de atenuación, especialmente en las bases pulmonares. La fusión más óptima se consigue en respiración suave, aunque no es la más adecuada para la evaluación del parénquima pulmonar, para la que es necesaria realizar una segunda TC en máxima inspiración

Presentamos el caso de una mujer de 57 años diagnosticada de carcinoma papilar de tiroides, tratada con tiroidectomía y radioyodo en dos ocasiones. Un rastreo de control muestra captación cervical derecha, confirmada por punción aspiración con aguja fina, tratada con linfadenectomía. Ante la elevación de tiroglobulina, el rastreo negativo y la ecografía/TC cervical inespecífica se realiza un estudio tomográfico por emisión de positrones/tomográfico computarizado (PET/TC) que confirma infiltración del lecho cervical. Adicionalmente se le realiza una TC en máxima inspiración que muestra cuatro micronódulos, uno de ellos no detectado por la TC del estudio PET/TC. El rastreo posterapéutico (I-131) confirma captación en estas localizaciones. Para la correcta interpretación de las imágenes PET/TC se necesita una fusión óptima de la PET y la TC, que minimice errores de corrección de atenuación, especialmente en las bases pulmonares. La fusión más óptima se consigue en respiración suave, aunque no es la más adecuada para la evaluación del parénquima pulmonar, para la que es necesaria realizar una segunda TC en máxima inspiración

We present the case of a 57-year old woman diagnosed of papillary thyroid carcinoma and treated with thyroidectomy followed by radioiodine (I-131) on two occasions. Follow-up radioiodine scan showed disease in right cervical region, confirmed by fine needle aspiration (FNA) and treated with lymphadenectomy. Due to thyroglobulin elevation, I-131 scan negative and inconclusive cervical ultrasonography/CT scan, we conducted a CT/PET study that confirmed cervical disease. An additional CT scan that was performed on maximum-inspiration showed four micro-nodules, one of which was not detected by the CT scan on shallow breathing (CT/PET). Post-treatment (I-131) scan confirmed uptake in these localizations. Good fusion between PET and CT images that avoids the errors of attenuation correction, especially in the lung bases, is necessary for correct image interpretation of the CT/PET study. Shallow breathing is necessary in order to obtain optimal image fusion with the CT/PET study, although this is not the best to evaluate pulmonary parenchyma in which an additional inspiratory CT scan improves detection of the pulmonary nodules

Inflamación granulomatosa por reacción de cuerpo extraño en estudio de PET/TAC con FDG en un paciente con recidiva tumoral de carcinoma colorrectal / Foreign body granulomatous inflammation in PET/CT scan study with FDG in a patient withtumor recurrence of colorectoral carcinoma

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Intravenous furosemide injection during 18F-FDG PET acquisition.

UNLABELLED: Urinary-system elimination of (18)F-FDG can be mistaken for pathologic uptake. Furosemide helps eliminate this artifact. Unnecessary administration should be avoided. Our approach obviates furosemide administration and other invasive procedures in many cases. METHODS: Thirty-seven cancer patients referred for PET to evaluate treatment response or suspected recurrence were prospectively studied using whole-body scanning, with (18)F-FDG injected via dorsal hand catheter beforehand. The catheter was left in place to enable injection of furosemide while the patient was inside the scanner. After abdominopelvic scanning, physicians evaluated the need to inject furosemide. Thirty minutes after furosemide injection, another abdominopelvic scan was obtained to detect postinjection urinary tract changes. RESULTS: Postfurosemide images showed effects due to physiologic elimination in 24 patients (64.9%), of whom 11 patients (45.8%) had more than one inconclusive prefurosemide finding. In 13 patients (35.1%), delayed images confirmed persistent lymph node uptake, including 3 patients (23.1%) with 1 lesion. CONCLUSION: Furosemide injection during scanning reduces artifacts, shortens examinations, and helps avoid invasive procedures.

[Role of FDG PET in the staging, recurrence and treatment response to imatinib (Glivec) in patients with gastrointestinal stromal tumors]. / Utilidad de la PET con FDG en el estudio de estadificación inicial, recurrencia y respuesta al tratamiento con imatinib (Glivec) en pacientes diagnosticados de un tumor del estroma gastrointestinal.

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) account for almost 4 % of all gastrointestinal neoplasms. Recently, a new type of tyrosine kinase inhibitor (Glivec), has been successfully used in patients with metastasic or unresectable disease. The aim of the study is to show the utility of PET in the staging, recurrence and treatment response to Glivec in GIST tumors. MATERIALS AND METHODS: 48 whole body FDG-PET studies in 27 patients with GIST (19 men/mean age = 56 y) were evaluated for initial staging (n = 13), recurrence (n = 15) or treatment response to Glivec (n = 20). Images were acquired in a whole body 2D mode using attenuation correction on an Advance Nxi G.E.MS camera and were evaluated visually and quantatively using SUV analysis. Results were compared with radiological findings, hystological confirmation or follow-up. RESULTS: In the initial staging evaluation, FDG-PET shows a more extensive disease than suspected in 3/10 patients. In other 3 patients PET ruled out mesenteric or peritoneal disease. In the evaluation of treatment response to Glivec, FDG-PET showed a good response in eleven patients (complete response in seven and partial response in four). In this group a sixty percent decrease of the SUV max was assessed. Two patients showed no response to Glivec at doses of 400 mg or 800 mg, showing a stable SUV value and/or increased in some abdominal lesions. PET detected recurrence in one patient. CONCLUSIONS: This study show how FDG-PET is accurate in the early treatment response to Glivec. PET could be helpful in the staging and recurrence of GIST tumors.