[en] Search for local or distant recurrence of malignant melanoma is not currently part of the French registration for FDG. In a preliminary study, the authors demonstrate the feasibility of this imaging using an 'hybrid' CDET gamma-camera in 2-D mode, with whole-body scanning (including arms and legs). In 7 patients who are currently evaluable, FDG-CDET resulted in performances better than or similar to conventional imaging, in all foci of melanoma recurrence. Data from literature using dedicated PET machines are consistent with the present preliminary results and strongly support the inclusion of this setting among the registered indications for FDG. (authors)

[en] Objective: The aim of this study was to evaluate the role of [F18]-FDG-CDET in the detection of recurrence of ovarian cancer. Methods and patients: After a fast of 6 hours, the patient (pt) was injected I. V. with 150-250 MBq of [F18]-FDG and imaging (whole-body scan and at least a tomoscintigram) was started 60 min. later, using a PICKER-MARCONI dual-head or triple-head CDET gamma camera. Between July 1997 and July 2001, 81 pts were studied for suspected recurrence of ovarian carcinoma. To date, the results of 62 pts are evaluable with reference to histology after surgery or concordance with conventional imaging and long-term follow-up. From these, 27 pts were referred for occult recurrence (OR) defined by an increase in serum CA-125 levels with negative CI and the remaining 35 pts for equivocal aspect at conventional imaging (ECI). Results: [F18]-FDG-CDET was true positive in 47 cases, 27 confirmed by histology after surgery (13 OC, 14 ECI) and the remaining 20 confirmed by evolution and concordance with CI. [F18]-FDG-CDET was true negative in 13 cases (6 OC, 7 ECI) as confirmed by spontaneous normalisation of CA-125 levels and no events during a 20-month follow-up for 11 pts and histology after surgery for 2 pts. [F18]-FDG CDET was false negative (FN) in 2 pts with ECI, 1 pt with a lymph node metastasis of less than 10 mm in size and 1 pt with continuing increase of CA-125 levels and still negative conventional imaging during a 8 month follow-up. No false positive results was reported in our study. In summary, the overall sensitivity, specificity and accuracy on a per patient basis were respectively 47/49 (96%), 13/13 (100%) and 60/62 (97%). The positive and negative predictive values were respectively 47/47 (100%) and 13/15 ( 87%). Conclusion: The present series of 62 patients gives valuable experience in CDET as compared to the cumulated data by Gambhir et al (J Nucl Med May 2001) reporting on a total of 357 patients using dedicated PET. Our CDET results are at least similar to those reported with dedicated PET cameras, which average values were Se=88%, Sp=90% PPV=85% and NPV=92% in this setting

[en] Positron Emission Tomography (PET) is a several decade old imaging technique that has more recently demonstrated its utility in clinical applications. The imaging agents used for PET contain a positron emmiter coupled to a molecule that drives the radionuclide to target organs or to tissues performing the targetted biological function. PET is then part of functional imaging. As compared to conventional scintigraphy that uses gamma photons, the coincidence emission of two 511 keV annihilation photons in opposite direction that finally results from by beta plus decay makes it possible for PET to get rid of the collimators that greatly contribute to the poor resolution of scintigraphy. In this article, the authors describe the basics of physics for PET imaging and report on the clinical performances of the most commonly used PET tracer: [¹⁸F]-fluorodeoxyglucose (FDG). A recent and promising development in this field is fusion of images coming from different imaging modalities. New PET machines now include a CT and this fusion is therefore much easier

No abstract available

[en] Positron emission tomography (PET) with [18F]-fluorodeoxyglucose is a very useful imaging technique in lymphomas occurring in the adult population. But there are very few data concerning its utility in childhood lymphoma, if it contributes to a more accurate staging of the illness and a better assessment of therapy. The purpose of our study was to evaluate the usefulness of performing FDG PET in childhood lymphoma compared to conventional imaging (CIM) and clinical data. Methods: From July 1998 to August 2001, 42 FDG PET examinations were performed using a dedicated PET system (27 examinations) or an hybrid coincidence PET system (15 examinations) for initial tumor staging (n=7), re-staging (n=5), assessment of therapy or residual masses (n=30) in 27 children with Hodgkin's disease (HD) (n=20) or non-Hodgkin's lymphoma (NHL) (n=7). FDG PET results were compared to CIM and clinical data. Since 2000, a standardized questionnaire for evaluation of the clinical impact of FDG-PET both on staging and on therapy has been sent to the 16 referring physicians and 13 replied. Results: FDG PET was performed in all children without any inconvenience. FDG PET was found to be very sensitive (Se=12/12) for staging and re-staging of the illness, showing more lesions than CIM with a 50% patient upstaging rate (6/12). It was very accurate for monitoring response to therapy and for characterisation of residual masses. False-positive results were observed in 2 NHL patients with thymic uptake and 1 false-negative result was observed in a patient with relapse of NHL, one month after a negative FDG PET. The questionnaire emphasized the impact of FDG PET on clinical management, as it was modified on the basis of the FDG PET results in 23% of patients. Conclusion: As previously demonstrated in the adult population, FDG PET appeared to be a very sensitive imaging technique for staging and re-staging of lymphoma in children and could be very useful to monitor response to therapy

[en] As for adult population, FDG PET is recognized as an efficient tool for staging, adaptation of therapy and follow-up of Hodgkin's disease in children. The interpretation of PET needs however to take into account some specificities of imaging as the frequent brown fat activation and the physiologic thymic uptake. The role of FDG PET in non Hodgkin's lymphoma (NHL) in children is less established. Although LNH are more frequent than Hodgkin 's lymphoma in children, FDG PET is rarely performed at diagnosis, probably due to the therapeutic emergency of these aggressive pediatric forms. During follow-up, FDG PET has been however shown to be useful, especially for the characterization of residual masses. (authors)

[en] Neoplasms of the pancreas may originate front both exocrine and endocrine cells but in 90% of the cases, they correspond to ductal adenocarcinomas. For adenocarcinomas, the major indication of FDG-PET corresponds to the pre-operative staging because unexpected distant metastases can be detected by FDG-PET in about 20 to 40% of the cases, which results in avoidance of unnecessary surgical procedures. FDG PET is also useful in evaluation of the treatment effect, monitoring after the operation and detection of recurrent pancreatic cancers. For the characterisation of the pancreatic tumour, the performance of FDG-PET is sometimes limited due to poor cellularity, hyperglycemia or inflammatory processes. especially for large tumours and is indicated only in cases of doubtful results of CT or MRI. For endocrine pancreatic tumours, FDG-PET is useful only in case of poorly-differentiated and aggressive tumours. F-DOPA PET can he useful, complementary to pentetreotide scintigraphy, in well-differentiated endocrine tumours. (authors)

No abstract available

[en] In prostate cancer, there has been a long-standing need for better imaging methods, to localise the primary lesions, stage the cancer, and evaluate its treatments. Molecular imaging with positron emission tomography (PET) and the most recent PET/CT fusion are indicated to detect cancer tissue on basis of its abnormal metabolic properties, with higher diagnostic performance than both conventional radiologic imaging and conventional scintigraphy. Fluorodeoxyglucose-(18F) PET or PET/CT: Fluorodeoxyglucose (FDG) is a glucose analogue designed for PET imaging. FDG PET has a recognised clinical utility in all the above settings of many major cancers (lung, colorectal, head and neck, melanoma, lymphoma, gynaecological cancers ...). But FDG PET has not proven to be regularly useful in any clinical setting of prostate cancer. Although it is able to detect aggressive, advanced or metastatic prostate cancer, the primary lesion itself frequently does not show-up significantly. For the detection of bone metastases, FDG PET is inferior to conventional bone scintigraphy and its performances are poor in the detection of post-treatment recurrences or recurrences responsible for rising prostate specific antigen (PSA) serum levels

[en] Full text: The aim of this study was to assess the clinical performances of FDG using a CDET system (hybrid dual-head MARCONI gamma camera with sodium iodine crystal 19 mm flick) or a dedicated PET system (C-PET, ADAC) for the detection of colorectal cancer recurrences. We report an experience of 4 years with CDET (July 1997 - July 2001) and of 1.5 years with PET (January 2000 - July 2001). After fasting for 6h or more, 3-5 MBq/kg (for 2D - CDET) or 2 MBq/kg (for 3D - PET) of [18F]-FDG were injected i.v. and imaging (whole-body scan and at least one tomoscintigram for CDET or scanning of the torso for PET) was started one hour later. Reconstruction was performed by an iterative algorithm. Attenuation correction by an external source was only available for PET. 304 examinations (ex) were performed with CDET and 164 with PET. 230 CDET cases and 73 PET cases are currently available according to histology or to follow-up. These examinations were performed for suspicion of recurrence (157 CDET cases, 39 PET cases), in search for other localization when one or more resectable lesion(s) was (were) known (48 CDET cases, 24 CDET cases) or for evaluation of the therapeutic efficacy (25 CDET cases, 10 PET cases). Globally, sensitivity was 89 % with CDET and 92 % with PET, specificity was 93 % with CDET and 100 % with PET and accuracy was 90 % with CDET and 93 % with PET. These results confirmed that FDG is a powerful tool for the detection of colorectal recurrences and showed that no significative difference in accuracy (chi2 = .75 ; p = .4) was detectable between the two modalities interpreted by the same team and both performed 1 hour after injection. (author)