Our objective was to prospectively explore the diagnostic value of 18 F-FDG PET/CT for preoperative staging in endometrial carcinomas and to investigate whether 18 F-FDG PET-specific quantitative tumor parameters reflect clinical and histologic characteristics. Methods: Preoperative 18 F-FDG PET/CT was prospectively performed on 129 consecutive endometrial carcinoma patients. Two physicians who did not know the clinical findings or staging results independently reviewed the images, assessing primary tumor, cervical stroma involvement and metastatic spread, and determining maximum and mean standardized uptake value (SUV max and SUV mean , respectively) for tumor, metabolic tumor volume (MTV), and total lesion glycolysis (TLG). All parameters were analyzed in relation to histomorphologic and clinical tumor characteristics. Receiver-operatingcharacteristic curves for identification of deep myometrial invasion and lymph node metastases were generated, and MTV cutoffs for predicting deep myometrial invasion and lymph node metastases were calculated. Results: The sensitivity, specificity, and accuracy of 18 F-FDG PET/CT for the detection of lymph node metastases were 77%-85%, 91%-96%, and 89%-93%, respectively. SUV max , SUV mean , MTV, and TLG were significantly related to deep myometrial invasion, presence of lymph node metastases, and high histologic grade (P , 0.015 for all) and independently predicted deep myometrial invasion (P , 0.015) and lymph node metastases (P , 0.025) after adjustment for preoperative histologic risk (based on subtype and grade) in endometrial biopsies. Optimal cutoffs for MTV in predicting deep myometrial invasion (20 mL) and the presence of lymph node metastases (30 mL) yielded odds ratios of 7.8 (P , 0.001) and 16.5 (P 5 0.001), respectively. Conclusion: 18 F-FDG PET/CT represents a clinically valuable tool for preoperatively evaluating the presence of lymph node metastases in endometrial carcinoma patients. Applying MTV cutoffs for the prediction of deep myometrial invasion and lymph node metastases may increase diagnostic accuracy and aid preoperative identification of high-risk patients, enabling restriction of lymphadenectomy for patients with a low risk of aggressive disease.

During the last decade, hybrid imaging has revolutionized nuclear medicine. Multimodal camera systems, integrating positron emission tomography (PET) or single photon emission computed tomography (SPECT) with computed tomography (CT) now combine the contrast provided by tumor-avid radioactive drugs with the anatomic precision of CT. While PET-CT to a great extent has replaced single-modality PET in adult oncology, the use of PET-CT in children has been controversial, since even the lowest dose CT protocols adds approximately 2 mSv to the radiation dose of about 4 mSv from the PET-study with F-18-fluorodeoxyglucose (F-18-FDG). The article describes the current techniques used, discusses radiation doses and gives an overview of current indications for PET-CT and SPECT-CT in children. Hybrid imaging with a tumor-avid radioactive drug provides extremely high contrast between tumor and background tissues, while the CT component helps to locate the lesion anatomically. Currently both PET-CT and SPECT-CT play a role in pediatric oncology; PET-CT using F-18-FDG particularly for staging and follow-up of lymphoma and brain cancer, bone and soft tissue sarcomas; SPECT-CT with I-123-metaiodobenzylguanidine (MIBG) for tumors of the sympathetic nervous system such as neuroblastoma and pheochromocytoma while the remaining neuroendocrine tumors are imaged with radioactively labeled somatostatin analogues. To reduce radiation dose, a low-dose CT in combination with ultrasound and/or magnetic resonance imaging for the assessment of anatomy is often preferred.

Centralized PET in the Western Norwegian health region meets the current clinical demand for patients residing in the three northern health trusts while patients from the most southern health trust receive approximately 30% fewer PET examinations. Access to specialized health care should be monitored routinely in order to identify inequalities in referral patterns and resource utilization.