Thyroid incidentalomas on fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography: incidence, malignancy risk, and comparison of standardized uptake values.

INTRODUCTION: To determine the incidence of fluorine-18-fluorodeoxyglucose (FDG) avid thyroid incidentalomas detected on positron emission tomography (PET) with integrated computed tomography (CT), and correlate the FDG-PET-CT findings to cytology. METHODS: A total of 942 FDG-PET-CT reports were retrospectively reviewed. Patients with FDG-avid thyroid incidentalomas were further reviewed for correlative cytology. RESULTS: The incidence of FDG-avid thyroid incidentalomas is 2.2%. Thyroid malignancies were identified in 3 of 6 patients who underwent cytologic correlation, with a positive predictive value of 50% (95% confidence interval, 14%-86%). The mean maximum standardized uptake values of benign and malignant FDG-avid thyroid incidentalomas were 5.6 and 6.6, respectively. CONCLUSION: A FDG-avid thyroid incidentaloma may predict underlying malignancy. Cytologic assessment should be considered for FDG-avid thyroid incidentalomas.

Dosimetric considerations in radioimmunotherapy and systemic radionuclide therapies: a review.

Radiopharmaceutical therapy, once touted as the "magic bullet" in radiation oncology, is increasingly being used in the treatment of a variety of malignancies; albeit in later disease stages. With ever-increasing public and medical awareness of radiation effects, radiation dosimetry is becoming more important. Dosimetry allows administration of the maximum tolerated radiation dose to the tumor/organ to be treated but limiting radiation to critical organs. Traditional tumor dosimetry involved acquiring pretherapy planar scans and plasma estimates with a diagnostic dose of intended radiopharmaceuticals. New advancements in single photon emission computed tomography and positron emission tomography systems allow semi-quantitative measurements of radiation dosimetry thus allowing treatments tailored to each individual patient.

[18F] FDG PET/CT in patients with fever of unknown origin: a local experience.

OBJECTIVE: 2-deoxy-2-[¹8F]fluoro-D-glucose positron emission tomography/computed tomography ([¹8F] FDG PET/CT) has become an established imaging tool in oncology and is now emerging in the field of infectious disease. The aim of this study is to assess the value of fluorine [¹8F] FDG PET/CT in the investigation of patients with fever of unknown origin (FUO). METHODS: [¹8F] FDG PET/CT scans and clinical data of 12 patients were reviewed. These patients met the revised definition criteria of FUO (febrile illness of greater than 3 weeks duration, temperature greater than 38.3°C and no diagnosis after at least 3 days of in-patient investigation or 2 weeks of outpatient investigation). A retrospective analysis of our local database was performed and evaluated for the diagnostic contribution of [¹8F] FDG PET/CT scans. RESULTS: An infective cause of the FUO was found in four (33.3%) patients, a neoplasm in two (16.7%) patients, non-infectious inflammatory disease or autoimmune in one (8.3%) patient. A definitive causative agent could not be found in five (41.7%) patients despite extensive investigations.In all, five (41.6%) patients had a PET/CT scan that was abnormal and was deemed 'helpful' as part of the investigation that pointed to the final diagnosis. Two (16.7%) patients had abnormal scans, which were deemed 'not-helpful' for the final diagnosis. CONCLUSION: [¹8F] FDG PET/CT can be helpful in some patients with FUO. This study adds value to the limited data published so far on this subject.

Intra-arterial rhenium-188 lipiodol in the treatment of inoperable hepatocellular carcinoma: results of an IAEA-sponsored multination study.

PURPOSE: Intra-arterial injections (IAI) of 131I-lipiodol is effective in treating hepatocellular carcinoma patients, but is expensive and requires a 7-day hospitalization in a radioprotection room. 188Re is inexpensive, requires no patient isolation, and can be used with lipiodol. METHODS AND MATERIALS: This International Atomic Energy Agency-sponsored phase II trial aimed to assess the safety and the efficacy of a radioconjugate 188Re + lipiodol (188Re-Lip) in a large cohort of hepatocellular carcinoma patients from developing countries. A scout dose is used to determine the maximal tolerated dose (lungs <12 Gy, normal liver <30 Gy, bone marrow <1.5 Gy) and then the delivery of the calculated activity. Efficacy was assessed using response evaluation criteria in solid tumor (RECIST) and alpha-feto-protein (alpha FP) levels and severe adverse events were graded using the Common Toxicity Criteria of the National Cancer Institute scale v2.0. RESULTS: The trial included 185 patients from eight countries. The procedure was feasible in all participating centers. One treatment was given to 134 patients; 42, 8, and 1 received two, three, and four injections, respectively. The injected activity during the first treatment was 100 mCi. Tolerance was excellent. We observed three complete responses and 19 partial responses (22% of evaluable patients, 95% confidence interval 16-35%); 1- and 2-year survivals were 46% and 23%. Some factors affected survival: country of origin, existence of a cirrhosis, Cancer of the Liver Italian Program score, tumor dose, absence of progression, and posttreatment decrease in alpha FP level. CONCLUSIONS: IAI of 188Re-Lip in developing countries is feasible, safe, cost-effective, and deserves a phase III trial.

Planar Tc99m--sestamibi scintimammography should be considered cautiously in the axillary evaluation of breast cancer protocols: results of an international multicenter trial.

BACKGROUND: Lymph node status is the most important prognostic indicator in breast cancer in recently diagnosed primary lesion. As a part of an interregional protocol using scintimammography with Tc99m compounds, the value of planar Tc99m sestamibi scanning for axillary lymph node evaluation is presented. Since there is a wide range of reported values, a standardized protocol of planar imaging was performed. METHODS: One hundred and forty-nine female patients were included prospectively from different regions. Their mean age was 55.1 +/- 11.9 years. Histological report was obtained from 2.987 excised lymph nodes from 150 axillas. An early planar chest image was obtained at 10 min in all patients and a delayed one in 95 patients, all images performed with 740-925 MBq dose of Tc99m sestamibi. Blind lecture of all axillary regions was interpreted by 2 independent observers considering any well defined focal area of increased uptake as an involved axilla. Diagnostic values, 95% confidence intervals [CI] and also likelihood ratios (LR) were calculated. RESULTS: Node histology demonstrated tumor involvement in 546 out of 2987 lymph nodes. Sestamibi was positive in 30 axillas (25 true-positive) and negative in 120 (only 55 true-negative). The sensitivity corresponded to 27.8% [CI = 18.9-38.2] and specificity to 91.7% [81.6-97.2]. The positive and negative LR were 3.33 and 0.79, respectively. There was no difference between early and delayed images. Sensitivity was higher in patients with palpable lesions. CONCLUSION: This work confirmed that non tomographic Tc99m sestamibi scintimammography had a very low detection rate for axillary lymph node involvement and it should not be applied for clinical assessment of breast cancer.

Relationship between acute pyelonephritis, renal scarring, and vesicoureteral reflux. Results of a coordinated research project.

Acute pyelonephritis (APN) may produce permanent renal damage (PRD), which can subsequently lead to diverse complications. We prospectively evaluated 147 females and 122 males (mean age 3.5 years) with APN in order to analyze the relationship between the presence of PRD, at the time of cortical renal scintigraphy, and age, gender, episodes of urinary tract infection (UTI), and presence of vesicoureteral reflux (VUR). There were 152 children studied after the first proven UTI. VUR was present in 150 children. PRD was observed in 170 children. There were no significant differences between boys and girls. PRD was found in 36.4% of children younger than 1 year and in 70.1% of those older than 1 year ( P<0.0001). Of children with VUR, 72% had PRD compared with 52% of children without VUR ( P<0.0001). Of children with a first episode of UTI, 55.9% developed PRD as did 72.6% of those with recurrent UTI ( P=0.004). Our results showed that PRD in children with APN is important, especially in the presence of VUR, recurrent UTI, and older age.

Diagnostic value of 99mTc-methylene diphosphonate and 99mTc-pentavalent DMSA compared with 99mTc-sestamibi for palpable breast lesions.

UNLABELLED: Different radiopharmaceuticals have been used to detect breast cancer. Among them, sestamibi has been extensively studied and has come to have a well-recognized role in the evaluation of palpable breast lesions. The goal of this study was to compare the diagnostic value of 99mTc-labeled compounds, such as methylene diphosphonate (MDP) and pentavalent dimercaptosuccinic acid (DMSA-V), with sestamibi for palpable breast lesions, in the scope of a multicenter trial sponsored by the International Atomic Energy Agency. METHODS: Patients from 7 countries were included: 47 women (mean age, 54 +/- 13 y) examined with MDP and sestamibi and 111 women (mean age, 55 +/- 12 y) examined with DMSA-V and sestamibi. Cancer was diagnosed in 41 of 49 lesions from the MDP group and in 78 of 113 lesions from the DMSA-V group. Axillary lymph node involvement was observed in 18 of 30 patients from the first group and in 27 of 53 patients from the second group. Prone scintimammography was performed using a dose of 740 MBq of each tracer, and diagnostic values were calculated from a masked interpretation of scans. RESULTS: In the first group, the sensitivity for sestamibi and MDP studies was 82.9% and 65.9%, respectively, with a specificity of 87.5% and 50%, respectively. In the second group, the sensitivity for sestamibi and DMSA-V studies was 87.2% and 65.4%, respectively, with a specificity of 77.1% and 74.3%, respectively. Regarding axillary involvement, the sensitivity was 33.3% for sestamibi in both groups, whereas the values for MDP and DMSA-V were 16.7% and 7.4%, respectively. In contrast, the specificity for sestamibi was 83.3% and 92.3% for the first and second groups, respectively, and the specificity for MDP and DMSA-V was 91.7% and 100%, respectively. CONCLUSION: Sestamibi is the most adequate alternative among the mentioned 99mTc-labeled radiopharmaceuticals for the evaluation of palpable breast lesions.