[PET/CT: focal lung uptake of 18F-fluorodeoxyglucose on PET but no structural alterations on CT]. / PET-TAC: captación pulmonar focal de FDG sin alteracion estructural en TAC.

The combination of positron emission tomography (PET) and computed tomography (CT) in a single device (PET/CT) offers a powerful diagnostic tool that opens up new horizons for imaging diagnosis. In order to correctly interpret PET/CT studies, knowledge of the biodistribution of 18F-fluorodeoxyglucose (FDG), the physiological variants as well as the pitfalls, including artefacts, which may be found, is necessary. We report four cases performed during the follow-up diagnostic context of an oncology study performed with 18F-FDG-PET/CT. In every case, this study showed focal uptake in the lung parenchyma in the PET study with no structural lesions being found on the CT scan. Radiotracer extravasation in three of these patients and a recent change in the injection protocol used suggest that an artefact was responsible for these discrepancies.

[Perivascular epithelioid tumors: Utility of the positron emission tomography with 18F-fluorodesoxyglucose (PET-TAC FDG) in their staging and follow-up]. / Tumor epitelioide perivascular uterino. Utilidad de la tomografía por emisión de positrones con (18)F-fluordesoxiglucosa en su estadificación y seguimiento.

Perivascular epithelioid tumors (PEComas) are a rare group of mesenchymal neoplasms with an unpredictable natural history and uncertain malignant potential. Uterine involvement and their association with tuberous sclerosis are typical for these tumors. We present a case of a 40-year old patient who was incidentally diagnosed of a uterine PEComa and serial studies of PET-CT with FDG were performed for staging and therapeutic response assessment. FDG PET-CT proved to be a valuable tool for detecting unsuspected pulmonary metastases and defining the reassessment of the patient after chemotherapy. The findings suggest that since this is a rare tumor, which does not always have benign behaviour, PET-CT may be a useful diagnostic imaging procedure for staging and clinical monitoring of patients who suffer this type of tumors.

[Fibrous dysplasia of the bone. Contribution of nuclear medicine in the diagnosis of suspicion of sarcomatous degeneration]. / Displasia fibrosa ósea. Aportación de la Medicina Nuclear al diagnóstico de sospecha de degeneración sarcomatosa.

Fibrous dysplasia (FD) is a relatively frequent benign disease of the bone in which there is a maturation disorder of the bone-forming mesenchyme where the lamellar bone marrow is replaced with abnormal fibrous tissue. Its diagnosis is often an accidental finding when X-ray studies or bone scans are performed for other reasons since it is usually asymptomatic. There may be complications such as deformities, pathological fractures and exceptionally malignant transformation. The differential diagnosis between malignancy and FD can be complicated and lead to late diagnosis when sarcomatous degeneration already exists. In this context, the positron tomography with (18)F-fluorodeoxyglucose (FDG-PET) may be useful in the monitoring of this condition. We present two cases of patients diagnosed of FD with suspicion of malignization of their bone lesions who were referred to Nuclear Medicin.

False positive in fluorodeoxyglucose-F18 positron emission tomography computed tomography scan of inferior vena cava leiomyoma in patient with a suspected paraganglioma. / Falso positivo en estudio de tomografía de emisión de positrones con fluorodesoxiglucosa-F18 de un leiomioma de vena cava inferior en paciente con sospecha de paraganglioma.

Leiomyomas are benign tumors derived from smooth muscle tissue that rarely present outside the uterus. These tumors do not usually show FDG uptake. We present the case of a patient with hypertension refractory to treatment and a lesion arising from inferior vena cava, that shows intense FDG uptake in PET/CT scan, suggestive of paraganglioma, with a final histological diagnosis of leiomyoma.

BNCT research activities at the Granada group and the project NeMeSis: Neutrons for medicine and sciences, towards an accelerator-based facility for new BNCT therapies, medical isotope production and other scientific neutron applications.

The Granada group in BNCT research is currently performing studies on: nuclear and radiobiological data for BNCT, new boron compounds and a new design for a neutron source for BNCT and other applications, including the production of medical radioisotopes. All these activities are described in this report.

Clinical and pathological factors related to 18F-FDG-PET positivity in the diagnosis of recurrence and/or metastasis in patients with differentiated thyroid cancer.

BACKGROUND: Objectives were to analyze the relationship between a positive (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) result and clinical and tumor factors in patients treated for differentiated thyroid cancer (DTC) and under suspicion of recurrence or metastasis, and to determine the diagnostic validity of PET in DTC patients with elevated serum thyroglobulin (Tg) and negative (131)I whole-body scan ((131)I-WBS). METHODS: We studied 50 DTC patients with elevated serum Tg and negative WBS treated with total thyroidectomy and (131)I ablation. Thyroxin treatment was withdrawn and patients were on iodine-free diet before WBS. Tg, anti-Tg antibodies, and thyroid-stimulating hormone (TSH) were determined. Patients with negative WBS and elevated Tg underwent PET study 1 week later. PET findings were verified by pathology findings or other imaging techniques [computed tomography (CT), magnetic resonance imaging (MRI), ultrasound (US)] and/or 12-month follow-up. The relationship between PET findings and tumor (histological type, size, multifocality, thyroid capsular invasion, lymph-node and/or metastatic involvement) and clinical (age at diagnosis, sex, Tg, accumulated iodine dose, and recurrence time) variables was analyzed. RESULTS: PET was positive in 32/39 patients with confirmed disease (82% sensitivity) and negative in 7/11 of disease-free cases (64% specificity), a positive predictive value (PPV) of 89%. Tumor size (P < 0.05) and thyroid capsular invasion (P < 0.05) were significantly associated with positive PET study. The relationship of PET findings with Tg levels and age at diagnosis was close to significance. CONCLUSION: (18)F-FDG-PET study offers a high sensitivity and positive predictive value (PPV) in patients with negative WBS and Tg positive. The use of FDG-PET is strongly recommended in DTC patients with large tumors, thyroid capsule invasion or poor-prognosis variants.

[18F-fluorodeoxyglucose positron emission tomography in the evaluation of therapy response assessment in lymphomas. Systematic literature review and meta-analysis]. / Tomografía de positrones con 18F-fluorodesoxiglucosa en la valoración de la respuesta de los linfomas al tratamiento. Revisión sistemática de la literatura y metaanálisis.

This systematic review of literature analyze the utility of positron emission tomography (PET or PET-CT) with 18F-fluorodeoxyglucose, as a diagnostic tool in the assessment of response to chemotherapy and immunotherapy in lymphomas, in terms of diagnostic accuracy in prospective publications. A literature search was conducted in major databases and through manual review from the reference lists of articles that were recovered. The methodological quality of the selected items was evaluated using the QUADAS questionnaire. 9 publications were analyzed after the filtering process. The methodological quality of the same was broadly acceptable. In patients with LH, the negative predictive value of FDG-PET after 2-3 cycles of chemotherapy, was ranged between 93.4% (95% CI, 92.6-94.3) and 100% (95% CI, 99.3-100%), and after the treatment, the negative predictive value of PET-FDG, was between 94.3% (95% CI, 92.8-95.7) and 100% (95% CI, 97.1-100). In patients with residual masses and LH, the meta-analysis of results showed a sensitivity of 100% (95% CI, 0.753-1) and a specificity of 84% (95% CI, 0.699-0.934). PET-FDG seems to be a useful tool to evaluate the response to treatment of patients with lymphoma. However, it recommended further prospective studies and that possibly conducted in hybrid PET-CT scans, to determine its usefulness.

[Gallbladder cancer staging with 18F-FDG PET-CT]. / Estadificación del cáncer de vesícula mediante tomografía de positrones con 18F-fluorodesoxiglucosa.

Gallbladder cancer is the most common biliary tract neoplasm. It generally affects the elderly, who are usually clinically asymptomatic. When symptoms appear, they suggest the presence of complications locally or due to tumour progression. Late diagnosis of the disease indicates a poor prognosis for these patients. Surgery is the only treatment with curative intent, but it is only possible in the early stages. Diagnostic imaging of this type of tumour is usually performed with ultrasonography, computed tomography or magnetic resonance cholangiography. Positron emission tomography (PET) with fluorodeoxyglucose (FDG) with dedicated scanners or hybrid PET-CT scans are new diagnostic tools which could help in the pre-surgical diagnosis of these tumours. We present three cases to illustrate the usefulness of PET-FDG in the pre-surgical staging of gallbladder cancer.

[Desmoid tumor of the thoraco-abdominal wall characterized with 18F-fluorodeoxyglucose PET/ CT scan. Correlation with magnetic resonance and bone scintigraphy. Review of the literature]. / Tumor desmoide de la pared torácico-abdominal. Caracterización con PET-TAC con 18F-fluorodesoxiglucosa y correlación con resonancia magnética y gammagrafía ósea. Revisión de la literatura.

Desmoid tumours are uncommon benign tumours but with aggressive behaviour, resulting from the proliferation of well-differentiated fibroblasts. Clinically, they present as a painless firm soft tissue mass. They can be solitary or multiple and have potential infiltrative capacity. When planning treatment, it is important to assess the correct tumour extent to permit curative radical surgery minimizing possible local recurrence. Different imaging techniques help to characterise these tumours. At present, magnetic resonance is the tool of choice for studying these tumours. The role of nuclear medicine techniques, such as bone scintigraphy, or more recently FDG-PET, has not been defined in the evaluation of these neoplasms. We present the case of a patient with a desmoid tumour of the abdominal-chest wall and we review the related literature.

[Usefulness of labelled red-cell scintigraphy in Blue Rubber-Bleb Nevus syndrome]. / Utilidad de la gammagrafía con hematíes marcados en el síndrome de Blue Rubber Bleb Nevus.

Blue Rubber Bleb Nevus syndrome is a rare disorder characterized by distinctive cutaneous and gastrointestinal venous malformations that usually cause episodes of occult gastrointestinal haemorrhage and iron deficiency anaemia. We describe an 8-year-old girl who had multiple cutaneous venous malformations since birth. She also suffered from several episodes of severe chronic iron deficiency anaemia and required blood transfusions. To evaluate the presence of gastrointestinal bleeding secondary to intestinal angiomatosis, we decided to perform 99mTc-labelled red blood cell scintigraphy, which confirmed cutaneous venous malformations and also showed gastrointestinal vascular lesions that suggested the diagnosis of Blue Rubber Bleb Nevus Syndrome.

125I radioactive seed localization for non-palpable lesions in breast cancer. / Semillas de 125I en la localización de lesiones no palpables en pacientes con cáncer de mama.

AIM: Marking of non-palpable breast lesions with 125I radioactive seeds is an alternative to the use of the surgical wire. The objective of this work is to present the results that we have obtained using radioactive seed localization compared to the reference technique in our center, the wire localization of non-palpable breast lesions. MATERIAL AND METHOD: Longitudinal prospective study that includes patients with histological diagnostic of breast cancer, with non-palpable lesions that are candidates to primary surgical treatment by radioactive seed localization (2016-2018) and by wire localization (2015-2016). Histological analysis of the surgical specimen was performed determining the status of surgical margins. The volume of the surgical specimen was calculated. RESULTS: A total of 146 patients were included, 95 who underwent surgery by radioactive seed localization and 51 by wire localization. The mean cube volume of the specimens were 135.67cm3 vs. 190.77cm3 (p=0.017), respectively. Eleven patients who underwent surgery by radioactive seed localization showed affected margins of the specimen (11.6%), versus 7 (13.2%) of wire localization group (p=0.084). Reintervention was performed in 9 of the patients marked with seeds and in 7 marked with wires (p=0.49). CONCLUSION: The use of 125I radioactive seeds is feasible in non-palpable breast lesions, with a low rate of reintervention and volumes of surgical specimens significantly lower than those obtained by wire localization.

Development of a positron emission tomography risks map. / Desarrollo de un mapa de riesgos para la tomografía por emisión de positrones.

Patient safety is an essential component of quality of care, especially when the complexity of care has reached extreme levels. Currently achieving this safety is considered a basic strategy of the National Health System. Nuclear Medicine departments have certain peculiarities that make them special in terms of patient safety, with situations that go beyond the common healthcare practice of other departments. Namely, that both encapsulated and non-encapsulated ionizing radiation is used in daily practice, and numerous groups of professionals must be coordinated to undertake positron emission tomography (PET) specifically, from the clinical management unit itself, and from other departments of the hospital (as well as companies outside the hospital itself and the Public Health System). The objective of this paper was to identify the risks to which a patient who is to be explored through PET can be exposed in a Nuclear Medicine department and draw up a risk map for the PET process. The methodology used is part of the proposal of the Ministry of Health (2007), and its practical implementation (given the limited literature available on Nuclear Medicine), follows as far as possible that of related care areas (radiodiagnosis and radiotherapy). For this purpose, a multidisciplinary team of professionals directly related to the PET process was created, using the modal analysis of faults and effects methodology to identify possible failures, their causes and the potential adverse events causing each. As a final step, a risk map was created, locating the previously identified faults at each stage of the process. This paper exposes the PET process, and describes the risks that patients might run when a PET scan is required, as well as the adverse events deriving from it. All this is shown in a risk map of the PET process.

[Circumscript myositis ossificans in a four-year-old boy]. / Miositis osificante circunscrita en un niño de cuatro años.

We present the case of a 4 year old boy with no previous personal or family history of interest, who attended the Paediatric Department of our hospital after a physical examination revealed a painful induration in the left arm which had increased in size; imaging tests were consistent with a calcified mass in soft tissues, without cortical involvement, suspected of being malignant. Two-phase bone scintigraphy was requested in which a soft tissue lesion, not suggestive of malignancy, was detected. The biopsy was negative for malignant cells. However, in view of the progressive increase in size of the lesion, FDG positron emission tomography (FDG-PET) was performed, showing a hypermetabolic mass consistent with malignancy in the left arm, for which the patient underwent surgery for suspected possible parosteal osteosarcoma.

[The role of bone scintigraphy in two cases of hereditary multiple exostoses]. / Papel de la gammagrafía ósea en dos casos de exóstosis múltiple hereditaria.

We present the cases of two patients aged 18 and 40 years, with no previous personal history of interest. The only symptoms reported by the first patient in the previous year were episodes of pain and stiffness without inflammation in the right knee and third finger of the right hand. These episodes lasted two to three weeks. Our second patient presented numbness in the lower left limb over the previous year. The analytical study was normal. The patients were diagnosed with hereditary multiple exostoses, based on the clinical, radiological and scintigraphic findings. The bone scintigraphy enabled whole body images to be obtained in a single examination and may be used for the differential diagnosis of other osteoarticular conditions, as well as for the follow-up and assessment of the response to treatment.

[Positron emission tomography with 18F-fluorodeoxyglucose in patients with uterine sarcoma]. / Tomografía por emisión de positrones con 18F-fluordesoxiglucosa en pacientes con sarcoma uterino.

OBJECTIVE: Describe our experience with 18F-fluorodeoxyglucose positron emission tomography (FDG-PET), in patients with uterine sarcomas, under suspicion of recurrence and in tumour staging after hysterectomy as an incidental pathology finding. MATERIAL AND METHODS: A retrospective review, between april 2002 and january 2006, of FDG-PET performed in 10 patients with clinical diagnosis of uterine sarcoma was made (7 patients under recurrence suspicion and three under initial staging). Mean age was 52.2 yrs. Evolution time after initial diagnosis vary from one month to 15 yrs (median time: 14 months). Lesions were classified as 8 leiomyosarcomas and 2 carcinosarcomas. FIGO staging were establish resulting 5 patients stage I, 1 patient stage III, and 4 patients stage IV. RESULTS: 4 of 7 patients under suspicion of recurrence showed discrepancies between positron emission tomography (PET) and conventional imaging techniques (CIT) information. FDG-PET was negative in three cases of non-conclusive CT. PET was negative in one case with pulmonary metastases. The 3 staging studies were concordant both FDG-PET and CIT images. Pathological information was obtained in 5 cases, and a mean time of 14 months of clinical follow up was made. CONCLUSIONS: FDG-PET can be useful in the follow up of uterine sarcoma patients, and also when it is an incidental finding in other causes hysterectomy.

Role of PET-CT with 18F-fluorocholine in biochemical recurrence after treatment of prostate cancer with curative intent. / Papel de la tomografía por emisión de positrones-tomografía computerizada con 18F-fluorocolina en la recidiva bioquímica tras tratamiento con intención curativa del cáncer de próstata.

OBJECTIVES: To analyse the ability of the PET-CT with 18F-fluorocholine (18F-FCH) to detect disease on biochemical recurrence after treatment with curative intent. To determine the clinical variables that would be able to optimise the test's diagnostic yield. MATERIAL AND METHODS: A retrospective study of PET-CTs with 18F-fluorocholine performed on 61 patients with prostate cancer who had undergone treatment with curative intent and met the criteria for biochemical recurrence. The results of the PET-CT were categorised into positive or negative and were validated using pre-established criteria. The relationship between the result of the PET-CT and the initial PSA nadir, PSA trigger, rising PSA velocity (PSAva) and PSA doubling time (PSAdt). The relationship between the metastatic sites on the PET-CT and the remaining variables was analysed. RESULTS: There was a 34.4% detection rate of the disease. The initial PSA, PSA nadir, PSA trigger and PSAva showed statistically significant differences according to the result of the PET-CT. The best discriminatory cut-off point between a positive or negative PET-CT for PSA trigger and PSAva was 3.5ng/ml and 0.25ng/ml/month respectively. The PSAdt was significantly lower in patients with remote disease compared to patients with localised disease (5.1 vs 16.8 months, P=.01). The probability that the PET-CT would detect remote disease vs localised disease was 3.2 times higher if the PSAdt was under 6 months (80% vs 20%, OR: 3.2, P=.02). In the multivariate analysis, only the initial PSA and not having undergone radical prostatectomy were demonstrated as independent predictive factors of a positive PET-CT result. CONCLUSIONS: The PET-CT with 18F-FCH can detect disease in a high percentage of patients with biochemical recurrence and provides information on its anatomical location. PSA kinetics and the patient's previous treatment are key variables in increasing the test's diagnostic.

[SAPHO syndrome]. / Síndrome SAPHO.

We report two cases, one 23 and one 27 year old man, with several years background of sternal and sternoclavicular joints pain, respectively. The laboratory tests were normal. Based on the clinical, radiologic and scintigraphic findings, SAPHO syndrome was diagnosed. Bone scintigraphy makes it possible to obtain a whole body scan in a single whole body scan, and can be used for differential diagnosis of other osteoarticular diseases and for evolutive control and therapeutic response.

[Positron emission tomography with fluordesoxyglucose-F18 in follow-up of endometrial cancer]. / Tomografía de emisión de positrones con fluordesoxiglucosa-F18 en el seguimiento del cáncer de endometrio.

OBJECTIVE: To assess the utility of FDG-PET in the follow-up of patients treated for endometrial cancer and with suspicion of recurrence according to conventional imaging methods (CT, MRI) and/or elevation of serum tumour markers. MATERIALS AND METHODS: Between April 2002 and December 2005, eleven patients underwent 17 FDG-PET studies (six with 2 studies); mean age was 63.4 yrs (range, 52-69 yrs) and time since diagnosis ranged from 11 months to 12 yrs (mean of 56 months). Initially, seven patients were in stage I, three in stage III and one in stage IV (FIGO classification). Histologically, they corresponded to 8 endometrioid carcinomas and 3 non endometrioid carcinomas. RESULTS: FDG-PET showed infradiaphragmatic uptake in 3 patients and disseminated disease in 7 cases. FDG-PET showed no uptake in one patient. CT (n = 7) or MRI (n = 7) detected infradiaphragmatic lesions in 5 patients and visceral lesions in 2. In 11 patients, tumour markers were elevated (CA125, n = 9; CA19.9, n = 2; CA15.3, n = 2). In 7 patients, FDG-PET modified the information yielded by conventional imaging techniques and in 4 patients, the FDG-PET contributed no additional information. In 2 patients, histologic confirmation of the lesions was obtained and in 9 patients, there were clinical follow-up (from 3 to 20 months, mean of 8.7 months) and imaging studies. CONCLUSIONS: FDG-PET is superior to CT and MRI for detecting recurrences in the follow-up of patients with endometrial cancer.

The role of early 18F-FDG PET/CT in therapeutic management and ongoing risk stratification of high/intermediate-risk thyroid carcinoma.

Little is known about the role in ongoing risk stratification of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) performed early after radioactive iodine (RAI) ablation in differentiated thyroid carcinoma (DTC). The aim of the study is to investigate whether 18F-FDG PET/CT performed early after RAI ablation is useful to detect disease and to influence therapy and ongoing risk stratification. Patients with high/intermediate risk of recurrent DTC were included. 18F-FDG PET/CT scan was performed within 6 months after RAI ablation. We confirmed results with other imaging techniques, pathology reports, or follow-up. We classified the patient response as excellent, acceptable, or incomplete. Modified Hicks criteria were used to evaluate clinical impact. We included 81 patients with high/intermediate risk of recurrent DTC. Forty-one (50.6%) had positive uptake in 18F-FDG PET/CT, with negative (131)I whole-body scan ((131)I WBS). Sensitivity, specificity, and diagnostic accuracy of 18F-FDG PET/CT were 92.5, 90.2, and 91.4%, respectively. 18F-FDG PET/CT results had an impact on therapy in 38.3% of patients. One year after initial therapy, 45.7% showed excellent response, 8.6% acceptable response, and 45.7% incomplete response. A statistically significant relationship was found between negative 18F-FDG PET/CT and excellent response (80 vs. 12.2%, p < 0.001; OR 52.8). 18F-FDG PET/CT scan performed early in surveillance of patients with high/intermediate-risk thyroid carcinoma provides important additional information not available with conventional follow-up methods and had a high impact on therapy. A negative 18F-FDG PET/CT predicts an excellent response to therapy in the new ongoing risk stratification.

The role of somatostatin receptor scintigraphy in patients with pituitary adenoma or post-surgical recurrent tumours.

To assess the role of scintigraphy with 111In-DTPA-D-Phe-octreotide (111In-octreotide) in the diagnosis of pituitary adenomas and in the evaluation of post-surgical recurrent or residual tumours, we performed scintigraphy with 111In-DTPA-D-Phe-octreotide (SRS) in 35 patients: 14 patients with confirmed pituitary tumours and 15 with confirmed recurrent tumours. Clinical, biochemical and histological analyses, conventional images (CT/MRI), and follow-up assessments during a period of 1 year to 4 years were recorded in all patients. In the present study, scintigraphy with 111In-octreotide showed positive uptake in 10 out of 14 patients with confirmed pituitary tumour and in 13 out of 15 patients with confirmed recurrent tumour, with an overall sensitivity of 79%. SRS showed better results in growth hormone (GH)- and prolactin (PRL)-secreting tumours (7/8 patients correctly identified) than in other adenomas (3/9). SRS detected recurrence of adenocorticotrophic hormone (ACTH)-secreting tumours (4/5 patients correctly identified) and non-secreting tumours (5/7 patients correctly identified). 111In-octreotide scintigraphy, in combination with other imaging modalities, is useful in the diagnosis and follow-up of pituitary tumours. It allows scar tissue to be differentiated from tumour recurrence after surgical treatment and ensures better selection of patients who will benefit from medical treatment with somatostatin analogues.