Recommendations of the Spanish Societies of Radiation Oncology (SEOR), Nuclear Medicine & Molecular Imaging (SEMNiM), and Medical Physics (SEFM) on (18)F-FDG PET-CT for radiotherapy treatment planning.

Positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) is a valuable tool for diagnosing and staging malignant lesions. The fusion of PET and computed tomography (CT) yields images that contain both metabolic and morphological information, which, taken together, have improved the diagnostic precision of PET in oncology. The main imaging modality for planning radiotherapy treatment is CT. However, PET-CT is an emerging modality for use in planning treatments because it allows for more accurate treatment volume definition. The use of PET-CT for treatment planning is highly complex, and protocols and standards for its use are still being developed. It seems probable that PET-CT will eventually replace current CT-based planning methods, but this will require a full understanding of the relevant technical aspects of PET-CT planning. The aim of the present document is to review these technical aspects and to provide recommendations for clinical use of this imaging modality in the radiotherapy planning process.

Impact of 18F-FDG PET/CT with retrograde filling of the urinary bladder in patients with suspected pelvic malignancies.

UNLABELLED: The purpose of this study was to assess the feasibility of selective pelvic PET/CT with retrograde bladder irrigation in evaluating pelvic pathologies. METHODS: Thirty-eight patients (22 women and 16 men), with a mean age of 61 y (range, 41-81 y) and a neoplastic background (most of them of pelvic pathology), were assessed with PET/CT. The most prevalent findings were urothelial (14 cases), gynecologic (12 cases), and rectal (7 cases) cancers. All but 3 patients had undergone previous surgical procedures or radio- or chemotherapy. Twenty-two patients had suspected pelvic pathology on a previous diagnostic CT scan. All the patients underwent a standard PET/CT protocol (from head to upper thighs) 60 min after the intravenous injection of 370 MBq of (18)F-FDG. Additional delayed pelvic PET/CT images were acquired with a filled-bladder technique. Both series of images were assessed by 2 experienced observers. A lesion was classified as malignant if it showed a standardized uptake value greater than 2.5 or, in the case of subcentimetric lesions, any uptake greater than background activity that persisted or increased on delayed pelvic imaging. All lesions were evaluated histologically or by clinical follow-up. RESULTS: Twenty-seven of 43 studies were categorized as pathologic using PET/CT. Nineteen studies showed abnormalities in the pelvis; the findings of 5 of these studies were false-positive. Ten studies showed pathologic (18)F-FDG uptake in the bladder wall; in 7 of these studies the uptake was found to be true-positive on histopathologic examination. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of PET/CT in the pelvic assessment were 100%, 83%, 74%, 100%, and 76%, respectively. The retrograde filling reduced the interference with physiologic urinary accumulation of (18)F-FDG in patients with possible pelvic lesions; no false-negative results were documented. CONCLUSION: In (18)F-FDG PET studies, retrograde filling of the urinary bladder is recommended to assess bladder wall lesions and malignancies in other pelvic locations.

Scintigraphic diagnosis of infectious complications in renal failure patients undergoing hemodialysis, continuous ambulatory peritoneal dialysis or renal transplant

Patients with end-stage renal disease have two therapeutic options, dialysis and renal transplantation. Infectious complications occurring in such patients will not only condition the effectiveness of such treatments, but are among the main causes of morbidity and mortality in such cases. Knowledge of the advantages and limitations of nuclear techniques is essential for management of these conditions.

Pacientes em estágio final de doença renal têm duas opções terapêuticas, diálise e transplante renal. Complicações infecciosas que ocorrem em cada paciente são as principais causas de morbidade e mortalidade nestes casos. Conhecimentos das vantagens e limitações de técnicas nucleares são essenciais para o acompanhamento nestas condições.