18-F fluorodeoxyglucose positron emission tomography indicating unsuspected infections in two patients with dermatomyositis.

Dermatomyositis is an idiopathic inflammatory myopathy that may be associated with malignancies. The technique of 18-F fluorodeoxyglucose (FDG)-positron emission tomography (PET) is an important tool to investigate underlying malignancy in patients with a possible paraneoplastic syndrome. We report two consecutive patients with dermatomyositis in whom 18-F FDG-PET revealed unsuspected infections. Physicians should be aware that a positive 18-F FDG-PET is not specific for malignancy and may reveal other conditions including an infectious disorder.

Prospective comparison of FDG and FET PET/CT in patients with head and neck squamous cell carcinoma.

AIM: The clinical usefulness of 2-deoxy-2-[F-18]fluoro-D-glucose-positron emission tomography (FDG-PET) in head and neck squamous cell carcinoma (HNSCC) is now well-documented. However, its sensitivity is greater than its specificity due to false-positive results in inflammatory or infectious lesions, which are frequent in this area, in particular after treatment by surgery and/or radiotherapy. O-2-fluoro-(18F)-ethyl-L-thyrosine (FET) has been reported not to be taken up by such lesions, and a preliminary study indicated that this may be clinically useful in HNSCC. We performed a prospective study to compare the diagnostic performances of FDG and FET PET/CT in the different settings of HNSCC. MATERIALS AND METHODS: Twenty-seven patients (20 men and seven women, aged 48-76, among 30 patients included) and 69 suspected cancer sites are now evaluable on basis of postsurgical histology and/or follow-up greater than 6 months; 15 patients were referred for initial staging and 12 during posttherapy follow-up, a recurrence being suspected in eight of them. FDG and FET PET/CT were performed on two different days, the patient fasting for 6 h, 1 h after injection of 5 MBq/kg of body mass of each radiopharmaceutical. Both PET/CT examinations were blind read more than 6 months after the end of inclusions in a random order for each tracer and with a time interval greater than 1 month between FDG and FET PET/CT blind readings. RESULTS: Overall diagnostic performances, derived from blind reading: FDG PET/CT on a per patient basis: sensitivity 100%, specificity 71%, accuracy 93%; FDG PET/CT on a per site basis: sensitivity 95%, specificity 63%, accuracy 83%; FET PET/CT on a per patient basis: sensitivity 70%, specificity 100%, accuracy 78%; FET PET/CT on a per site basis: sensitivity 64%, specificity 100%, accuracy 78%. At site level, sensitivity was significantly greater with FDG (p<0.02) and specificity with FET (p<0.01). The statistical level of significance was not reached at patient level. CONCLUSION: Although its good specificity was confirmed, FET did not appear to be suited as a first-line PET tracer in HNSCC imaging and cannot replace FDG for staging due to insufficient sensitivity. However, it was useful in a few selected cases to favor a wait and see attitude when a FDG+ FET- focus was discovered in patients referred for systematic FDG PET during follow-up. In contrast, second primary cancers should not be ruled out if FDG was clearly positive in the lungs or the digestive tract.

The sentinel lymph node procedure for patients with preoperative diagnosis of ductal carcinoma in situ: risk factors for unsuspected invasive disease and for metastatic sentinel lymph nodes.

BACKGROUND: Occult invasive disease could be found at definitive histology in patients initially diagnosed with large ductal carcinoma in situ (DCIS). Sentinel lymph node (SLN) biopsy is a reliable and minimally invasive procedure providing axillary information and avoiding a second operation in this particular group of patients. The aim of our study was to assess the value of SLN biopsy in patients with large DCIS who are at highest risk for being upstaged to invasive carcinoma. PATIENTS AND METHODS: The study included 195 patients diagnosed with DCIS upon initial core biopsy and undergoing SLN biopsy. Many features were correlated with the presence of unsuspected invasive disease and positive SLN biopsy using univariate and multivariate analyses. RESULTS: Of the 110 patients with pure DCIS, seven patients (6%) had a metastatic lymph node; 31 patients (16%) were found to have invasive disease upon final histology. Univariate analysis of predictors of unsuspected invasive carcinoma showed that patients having a preoperative biopsy that indicated DCIS with microinvasion (DCISM) or large DCIS were at a higher risk of invasive carcinoma after histological examination of the operative specimen. Of the 31 patients who were upstaged to invasive carcinoma at final histology, seven patients (22%) had a positive SLN biopsy. The analysis of predictors of positive SLN in our study shows that diffuse DCIS requiring mastectomy is the main risk factor for SLN metastasis. CONCLUSION: There are no real predictive factors for invasive disease in patients with an initial diagnosis of DCIS or DCISM. Our study supports the value of SLN biopsy in patients with a preoperative DCISM biopsy or patients with a large pure DCIS biopsy requiring mastectomy.

MRI and FDG PET/CT findings in a case of probable Heidenhain variant Creutzfeldt-Jakob disease.

Creutzfeldt-Jakob disease (CJD) is a neurodegenerative disease caused by the accumulation of a pathogenic isoform of a prion protein in neurons that is responsible for subacute dementia. The Heidenhain variant is an atypical form of CJD in which visual signs are predominant. This is a report of the case of a 65-year-old man with probable CJD of the Heidenhain variant, with topographical concordance between findings on magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (FDG) photopenic areas on positron emission tomography (PET)/computed tomography (CT) for cortical parietooccipital lesions.

[Imaging and PET-CT of adult and childhood lymphoma]. / Imagerie radiologique et TEP scanner des lymphomes de l'adulte et de l'enfant.

Malignant lymphomas are lymphoproliferative disorders arising in both lymphoid tissue and non-lymphoid organ systems. Treatment rarely is surgical, and currently relies on a combination of chemotherapy and radiation therapy. The role of imaging is to determine the spread of the disease, to identify targets and to assess therapeutic response. Imaging techniques mainly use morphological criteria, and may underestimate infiltrative disease, as observed in bones. The frequent presence of residual masses after treatment usually prevents classification of patients as complete response. Over time, positron emission tomography (PET) with F18-fluorodeoxyglucose (FDG) has become a prominent part of the workup at diagnosis and during follow-up. Recently, PET has been integrated in the revised response criteria for malignant lymphoma.

[Assessment of tumor radiosensitivity using functional and metabolic nuclear imaging in research and clinical practice. A review]. / Evaluation de la radiosensibilité tumorale par l'imagerie fonctionnelle et métabolique : de la recherche à l'application clinique. Revue de la littérature.

During the last half of century considerable research on radiosensitivity biomarkers has been published. However, to date there is no non-invasive marker of cellular radiosensitivity identified for clinical routinely use. In this review, the main functional and metabolic imaging isotopic techniques for tumor radiosensitivity that have been explored over the last years are being described. This indirect evaluation fall into 3 topics associated with tumor proliferation rate or apoptosis, tumor hypoxic fraction, neoangiogenesis and the intrinsic radiosensitivity of clonogenic tumor cells. The final objective of the radiosensitivity monitoring during radiotherapy would be to adapt treatment strategy for overcoming the identified radioresistance mechanism such as hypoxia by the addition of radiosensitisers for example. This would allow better tumor control rather than continue inefficient and costly treatment delivery, which in addition could compromise outcome.

[18F-FDG PET and bone scintigraphy to search for bone metastasis of lung cancer]. / TEP au FDG-(18F) et scintigraphie du squelette dans la recherche de métastases osseuses du cancer broncho-pulmonaire.

Initial staging of lung cancer is essential to determine the appropriate therapeutic strategy. 18F-FDG PET is currently considered to be the gold standard. 99mTc bisphonate bone scintigraphy has long been indicated to search for bone metastases but it is not know whether this exploration adds further information after an 18F-FDG PET scan. In order to answer this question, two observers unaware of the clinical situation reread PET scans and bone scintigraphies and results compared with other imaging findings. Between February 2001 and March 2004, 39 patients (13F, 26M, 62 +/- 11 yr) underwent 18FFDG PET and bone scintigraphy (mean interval 17 +/- 17 d). When the two explorations agreed for the diagnosis of bone extension, we considered that bone scintigraphy added nothing. When the two explorations were in disagreement, the other imaging examinations, the clinical features and laboratory results during the five-month minimal follow-up were used to establish the reference diagnosis. 18F-FDG PET and bone scintigraphy were in agreement in 29 patients (74%) with positive results in 12 (31%) and negative results in 17 (43%). The two explorations were in disagreement in 10 patients (26%). Among the five disagreement cases with positive bone scintigraphy and no bone anomaly on the 18F-FDG PET, the anomalies were benign and explained by clinical features (3 patients) or were not confirmed by the clinical course and laboratory results (2 patients). Among the 5 cases with a bone anomaly on the 18F FDG PET, no metastasis could be identified during clinical follow-up. Bone scintigraphy does not enable identification of any bone metastases which were not recognized on the PET scan and therefore should not be performed systematically. Using a computed tomography scan with the 18F-FDG PET could further limit the contribution of bone scintigraphy by providing more precision concerning foci identified on the PET scan.

[Impact of computed tomography (CT) and 18F-deoxyglucose-coincidence detection emission tomography (FDG-CDET) image fusion for optimisation of conformal radiotherapy in non-small-cell lung cancers]. / Tomographie par émission de positons et détection en coïncidence (TEDC) et recalage d'images de simulation virtuelle par tomodensitométrie. Impact sur la planification de la radiothérapie conformationnelle des cancers bronchiques non à petites cellules.

UNLABELLED: To report a retrospective study concerning the impact of fused 18F-fluorodeoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on three-dimensional conformal radiation therapy (3D-CRT) planning for patients with non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: One hundred and one patients consecutively treated for stages I-III NSCLC were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define target volume. RESULTS: FDG-PET identified previously undetected distant metastatic disease in 8 patients making them ineligible for curative CRT (one patient presented some positive uptakes corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because fused CT/PET images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT/PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was > or = 25% in 7 patients because CT/PET image fusion reduced pulmonary GTV in 6 patients (3 patients with atelectasis) and mediastinal nodal GTV in 1 patient. The GTV increase was > or = 25% in 14 patients due to an increase of the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Among 81 patients receiving a total dose > or = 60 Gy at ICRU point, after CT/PET image fusion, the percentage of total lung volume receiving more than 20 Gy (VL20) increased in 15 cases and decreased in 22 cases. The percentage of total heart volume receiving more than 36 Gy increased in 8 patients and decreased in 14 patients. The spinal cord volume receiving at least 45 Gy (2 patients) decreased. After multivariate analysis, one single independent factor made significant effect of FDG/PET on the modification of the size of the GTV: tumor with atelectasis (P = 0.0001). Conclusion. - Our study confirms that integrated hybrid PET/CT in the treatment position and coregistered images have an impact on treatment planning and management of patients with NSCLC. FDG images using dedicated PET scanners with modern image fusion techniques and respiration-gated acquisition protocols could improve CT/PET image coregistration. However, prospective studies with histological correlation are necessary and the impact on treatment outcome remains to be demonstrated.

[Impact of computed tomography (CT) and 18F-deoxyglucose positron emission tomography (FDG-PET) image fusion for conformal radiotherapy in esophageal carcinoma]. / Tomographie par émission de positons et fusion d'images de simulation virtuelle par tomodensitométrie. Impact sur la planification de la radiothérapie conformationnelle des cancers de l'oesophage.

PURPOSE: To study the impact of fused (18)F-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on conformal radiation therapy (CRT) planning for patients with esophageal carcinoma. PATIENTS AND METHODS: Thirty-four patients with esophageal carcinoma were referred for concomitant radiotherapy and chemotherapy with radical intent. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. PET-images were coregistered using five fiducial markers. Target delineation was initially performed on CT images and the corresponding PET data were subsequently used as an overlay to CT data to define the target volume. RESULTS: FDG-PET identified previously undetected distant metastatic disease in 2 patients, making them ineligible for curative CRT. The Gross Tumor Volume (GTV) was decreased by CT and FDG image fusion in 12 patients (35%) and was increased in 7 patients (20.5%). The GTV reduction was >or=25% in 4 patients due to reduction of the length of the esophageal tumor. The GTV increase was >or=25% with FDG-PET in 2 patients due to the detection of occult mediastinal lymph node involvement in one patient and an increased length of the esophageal tumor in the other patient. Modifications of the GTV affected the planning treatment volume (PTV) in 18 patients. Modifications of delineation of GTV and displacement of the isocenter of PTV by FDG-PET also affected the percentage of total lung volume receiving more than 20 Gy (VL20) in 25 patients (74%), with a dose reduction in 12 patients and a dose increase in 13 patients. CONCLUSION: In our study, CT and FDG-PET image fusion appeared to have an impact on treatment planning and management of patients with esophageal carcinoma related to modifications of GTV. The impact on treatment outcome remains to be demonstrated.

Current applications of PET imaging of sex hormone receptors with a fluorinated analogue of estradiol or of testosterone.

Currently, the most frequent approach in the oncologic applications of positron emission tomography (PET) is detecting the hypermetabolic activity of the cancer tissue. A more specific approach, which may be complementary, is detecting the overexpression of receptors. In this review article, we aim to evaluate the results that are currently available for PET imaging of the sex hormone receptors in clinical oncology. The indication of PET and now PET/CT has been more disputed in breast carcinoma than in many other primary cancers (e.g., lung, head and neck, colorectal, lymphoma). 18F-fluorodeoxyglucose (FDG), the glucose analogue for PET imaging, has a limited sensitivity to detect the primary breast tumors in case of lobular or in situ forms or small sized tumors localised on systematic mammography, and to identify minimal node invasion in the axilla. Using 16α-[¹8F]fluoro-17ß-estradiol (FES), a fluorinated estradiol analogue, PET is able to detect the over-expression of the oestrogen receptor (ER) in lesions, at a whole-body level. FES and FDG appear complementary for a better diagnostic performance in staging locally advanced breast cancer or restaging recurrent or metastatic breast cancer. Another potential indication is predicting the response to starting or resuming hormone therapy in patients with metastatic breast cancer, in relation with the ER status of all lesions revealed by FES PET. In two retrospective studies, FDG PET was also able to predict the response to hormone therapy, on basis of a metabolic flare, observed either after 7-10 days of treatment or during an estradiol challenge. A prospective comparison of those approaches is warranted. One study reported predicting response to neoadjuvant chemotherapy thanks to a low value of FES SUV(max) or FES/FDG SUV(max) ratio. The presence of ER in uterine tumors, including the benign ones, in ovarian cancers or even in meningiomas, may have therapeutic consequences and FES PET could have a clinical utility in those settings; only initial results are available. The indication of PET and PET/CT has been even more disputed in prostate carcinoma, due to the lack of significant FDG uptake in most cases, at least before the castration-resistant stage. Using FDHT, a fluorinated testosterone analogue, PET is able to detect the over-expression of the androgen receptor (AR) in lesions, at a whole-body level. At least partly due to the rather large number of alternative tracers that are in development or even routinely available in some countries, few FDHT studies have been published until now. From absorbed dose values previously published for FES by the team of University of Washington School of Medicine at Seattle, and for FDHT by the teams of Memorial Sloan-Kettering Cancer Center at New York and of Washington University at St. Louis, we applied the coefficients of ICRP publication 103 and calculated an effective dose per unit of injected activity of 0.023 mSv/MBq for FES and 0.018 mSv/MBq for FDHT. The radiation exposure is of the same order of magnitude as with FDG.

[18F]-FDG positron imaging in clinical management of lymphoma patients.

[18F]-FDG is a glucose analogue labelled with a short-lived positron emitter. During the past decade, it has been proposed to detect in vivo lymphoma lesions with PET, a new non-invasive imaging modality. We aimed at reviewing the current experience with FDG in several clinical settings of lymphoma. Due to the lack of specificity of FDG for lymphoma, histology remains compulsory to establish the diagnosis. Nevertheless, in the case of AIDS, FDG imaging has been proposed to differentiate lymphoma and opportunistic infections in brain lesions. To explore lymphoma extension, FDG-PET highlights more lesions than CT or the clinical examination and results in upstaging 13% of cases. It could also be used for selecting a site for biopsy when the location considered first clinically is difficult to access. Staging lymphoma with FDG-PET also provides baseline images for subsequent evaluation of therapy, which is one of the most promising indications: a negative scan predicts response to therapy and subsequent remission with a predictive value of 89%, and a positive scan either reflects resistance or predicts relapse with a predictive value of 83%. The current achievement of FDG imaging is the early detection of recurrence or of viable tissue in residual masses that remain several months after treatment. Both its sensitivity (84%) and its specificity (95%) overwhelm the values of conventional imaging, mainly CT and gallium-67 scintigraphy. When PET, as a new clinical imaging modality, is not yet widely demanded by clinicians and/or the number of FDG examinations is less than 500 per year, a 'hybrid' gamma-camera or CDET can be an alternative to dedicated PET. For 3 years, we have been using FDG-CDET in the 2D mode without attenuation correction, and obtained the following accuracy in a total of 40 examinations that could be evaluated: 85% for assessment of chemotherapy and 92% to detect recurrences and evaluate residual masses. Our preliminary results also stress the interest in FDG examination in childhood lymphoma, with the same indications as in adults.

Evaluation of FDG uptake by renal malignancies (primary tumor or metastases) using a coincidence detection gamma camera.

UNLABELLED: The aim of this study was to evaluate the usefulness of FDG scanning using an ordinary gamma camera equipped with coincidence detection (CDET) for 2 renal cancer indications: characterization and staging of renal masses before nephrectomy and search for recurrence after nephrectomy. METHODS: Between September 1997 and June 1998, a whole-body scan and at least 1 tomoscintigram were obtained on 23 occasions in 22 patients (fasting for at least 6 h) using a Prism XP 2000 CDET gamma camera; scanning was begun 45 min after intravenous injection of 150-250 MBq FDG. RESULTS: Postoperative histologic evidence was obtained from 13 of 16 patients who underwent FDG using a CDET gamma camera before renal surgery; 4 renal masses did not accumulate FDG (3 true-negatives, 1 false-negative), whereas 9 renal tumors accumulated FDG (8 true-positives, 1 false-positive). In the other 3 patients, only 1 extrarenal site of FDG uptake was checked and confirmed on histologic examination: a bone metastasis from renal cell carcinoma in 2 cases and lymph node metastasis from a squamous cell carcinoma (3 true-positives). The primary local and regional staging of the malignant renal tumors was accurate in the 9 patients who underwent nephrectomy (8 true-negatives, 1 true-positive). The primary distant staging was positive in 1 case (focus in the chest corresponding to a probable true-positive on follow-up). In the 7 examinations performed because of suspected recurrence of renal cell carcinoma several months after nephrectomy, metastases were visualized by FDG in 4 patients, confirmed by biopsy in 2 patients, and confirmed by conventional imaging or follow-up (or both) in 2 patients. The other 3 patients had negative FDG scans, corresponding to probable true-negative results on follow-up. CONCLUSION: FDG using a CDET gamma camera can be used effectively for the staging and restaging of renal tumors and might be useful for characterization of the primary renal tumor in doubtful cases.

Use of a coincidence gamma camera to detect primary tumor with 18fluoro-2-deoxy-glucose in cervical lymph node metastases from an unknown origin.

This study was performed to evaluate the ability of a dual-head gamma camera with 18fluoro-2-deoxy-glucose coincidence detection emission tomography (FDG-CDET) to detect primary tumors in patients with cervical lymph node metastases of head and neck squamous cell carcinoma from an unknown origin. From 60 patients with untreated head and neck squamous cell carcinoma, we selected 4 in whom no evidence of the primary's origin was found by the conventional methods used for the evaluation of head and neck tumors. In addition to the panendoscopy, chest radiography, a computed tomography (CT) scan, and FDG-CDET were performed. Both FDG-CDET and the CT scan located cervical lymph node metastases. In addition, FDG-CDET located the primary tumor in 3 of the 4 patients, and the tumors were confirmed with histopathologic findings. In contrast, the CT scan detected the primary tumor in none of them. FDG tomography performed on a coincidence gamma camera appears to be a successful new tool in detecting occult primary tumors in head and neck carcinoma, and is useful in guiding endoscopic biopsies. It has, further, the important potential ability to detect distant metastases on whole body images.

[18F]-FDG uptake in soft tissue dermatome prior to herpes zoster eruption: an unusual pitfall.

Authors report on a case of [18F]-fluorodeoxyglucose ([18F]-FDG) uptake in the soft tissue of a patient referred for [18F]-FDG coincidence detection emission tomography (CDET) in a search for recurrence of colorectal cancer. A herpes zoster eruption occurred in the same site within two days, but was spontaneously resolved. To the best of our knowledge this is the first description of a false positive [18F]-FDG result in relation to a viral infection of soft tissue. It shows that interpretation of subcutaneous foci has to be cautious in patients with or without a past history of herpes zoster even in pain-free areas and prior to skin eruption.

[(18F)-fluoro-2-deoxyglucose PET in imaging of gynecologic cancers]. / La TEP au [18F]-fluoro-2-désoxyglucose dans l'imagerie des cancers gynécologiques.

Although gynaecological cancers are not currently part of the clinical indications in the French registration for [18F]-fluoro-2-deoxyglucose (FDG), various studies indicate in this context a potential clinical benefit of imaging with this radiopharmaceutical and PET, a new imaging modality that can be performed either with a dedicated machine or with a "hybrid" gamma-camera (CDET). The potential indications of FDG-PET in mammary, ovarian or cervical cancers are reviewed according to the diagnostic phase: screening, tumour characterisation, staging, therapeutic follow-up and search for recurrence. By pooling the published results, the accuracy of FDG-PET could be estimated with a reasonable precision in various clinical settings: characterisation of a breast tumour (598/696 = 86%), lymph node invasion in breast cancer (525/602 = 87%), recurrence of breast cancer (114/127 = 90%), characterisation of adnexal masses (130/176 = 78%), recurrence of ovarian cancer (152/172 = 88%), lymph node invasion in cervical cancer (98/103 = 95%). Authors also present original data concerning their experience of recurrence detection with CDET in breast or ovarian cancers. In 44 patients suspicious of recurrence of breast cancer, FDG-CDET sensitivity was 94%, specificity 82% and accuracy 91%; in 18 patients suspicious of recurrence of ovarian cancer, specificity, sensitivity and accuracy were 100%. The impact of dedicated PET and CDET examinations performed by our team during year 2000, led, according to 63 forms returned to us, to a modification of stage in 48% of breast cancers, 36% of ovarian cancers, 43% of cervical cancers and above all induced a modification in patients' management in respectively 69%, 64% and 60% of cases, more than the average rate in cancer patients which was 50%. No significant difference was observed between clinical impact of dedicated PET and CDET examinations.

[Value of [18F]-fluorodeoxyglucose (FDG) positron emission tomography in digestive cancerology]. / Apport de la tomographie par émission de positons au [18F]-fluorodésoxyglucose (FDG) en cancérologie digestive.

COLORECTAL CANCERS: FDG-PET is a very effective tool in the follow-up of colorectal cancer for the early detection of recurrences, the search for other localisations in case of resectable lesions and for the evaluation of therapies. For the other digestive cancers, the data in the literature are less abundant and they do not yet have Marketing Authorization in France. OESOPHAGEAL CANCER: FDG-PET appears very promising for staging and detection of recurrences of oesophageal carcinomas. Pancreatic cancer Although the indication is difficult, FDG-PET appears superior to morphological techniques for the characterization and the locoregional staging of pancreatic tumours. BILARY AND GASTRIC CARCINOMAS: FDG-PET is promising but its role has to be confirmed in larger series for the detection of biliary and gastric carcinomas. OTHER DIGESTIVE TUMOURS: In cases of hepatocarcinoma, FDG-PET appears efficient only in cases of undifferentiated tumours, and in cases of malignant neuroendocrine digestive tumours, is useful in combination with somatostatin receptor imaging.

[Assessment of a neuroendocrine tumour by 111In-pentetreotid scintigraphy and PET with 18FFDOPA and 18F-FDG]. / Valoración de un tumor neuroendocrino mediante gammagrafía con 111In-pentetreótido y PET con 18F-FDOPA y 18F-FDG.

We present the case of a 67 year old patient diagnosed of a neuroendocrine carcinoid tumour of the small intestine. The tumour and subsequent metastases were resected previously by surgery, but a new recurrence was suspected. CT showed left adrenal enlargement. 18F-FDG PET was normal and 111In pentetreotide scintigraphy showed liver and left diaphragmatic uptake. 18F-FDOPA PET showed uptake foci in liver and left diaphragm and also in left adrenal gland, retro urinary bladder area and multiple foci in abdominopelvic region, suggesting a peritoneal carcinomatosis. 18F-FDOPA PET was the first imaging modality to assess the extensiveness of the disease that was confirmed six month later by CT. Neuroendocrine tumors are a heterogeneous group of neoplasia. They are studied by conventional radiologic and functional techniques of nuclear medicine. This case illustrates the need to use the different techniques and tracers according to the characteristics of the tumor to be studied to thus improve the diagnostic and prognostic performance.