Objective The aim of this study was to evaluate the diagnostic performance of combined fluorine-18 fluorodeoxyglucose (18F-FDG) PET/contrast-enhanced computed tomography (Ce-CT) in comparison with Ce-CT alone for the detection of residual/recurrent tumor after initial treatment of malignant ovarian tumors. Patients and methods The study prospectively recruited 111 patients with a clinical suspicion of ovarian tumor recurrence. Each patient underwent 18F-FDG PET/ computed tomography (CT) with low-dose CT, followed immediately by Ce-CT. Study-based analyses for a total of 136 scans were carried out. For each study, 11 subsites were assessed on a four-point score (score 0 = definitely benign, score 1 = probably benign, score 2 = probably malignant, and score 3 = definitely malignant). The subsites were collectively categorized into four groups: local tumor site, peritoneum, pelvi-abdominal lymph nodes, and other sites (e.g. liver, lung, bone, brain, etc). The final diagnosis of disease status was made on subsequent follow-up by conventional imaging (CT/MRI), 18F-FDG PET/CT, or histopathology whenever possible. Results Ofthe136studiesevaluated,97(71%)studieshad recurrent/residual disease and 39 (29%) studies were disease free on the basis of the final diagnosis. 18F-FDG PET/Ce-CT and Ce-CT had a sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of 96 versus 84%, 92 versus 59%, 90 versus 59%, 97 versus 84%, and 95 versus 76%, respectively. 18F-FDG PET/Ce-CT was significantly more sensitive, specific, and accurate compared with Ce-CT, with P-values of 0.002, 0.001, and less than 0.0001, respectively. Site-based analyses also showed significant differences. Conclusion Combined18F-FDG PET/Ce-CT significantly outperforms Ce-CT alone in the post-treatment detection of malignant ovarian tumors.

Purpose: To identify the non-neoplastic variants of the sternal uptake in patients known to have a primary tumor, referred for detection of metastases elsewhere. Materials and methods: This retrospective study was approved by the Institutional Review Board. Fifty eligible patients (17 males & 33 females) known to have a primary tumor underwent 99mTc- MDP-bone scan for detection of metastases. All patients underwent SPECT/CT of the chest region. For each patient, 10 subsites were evaluated (right & left sternoclavicular joints, right and left first costo-sternal articulation, manubrium sterni, manubriosternal junction, body of the sternum, xiphisternal junction, xiphoid process and other sub-sites (e.g. chondro-sternal articulations)). The uptake was described as normal or abnormal. CT findings were categorized as normal/abnor- mal (arthritis, degenerative, developmental & congenital). Any patient with suspicious metastatic sternal lesion based on CT findings or abnormal tracer uptake was excluded. Results: A total of 500 sub-sites were analyzed. Increased uptake was seen in 189 sub-sites. Of them, 133 showed abnormal CT findings (95 arthritis, 33 degenerative, 3 developmental & 2 con- genital) and 56 sites were unremarkable. Of the 311 with normal uptake, only 18 showed abnormal CT findings (8 arthritis & 10 degenerative). The association was statistically significant (P 0.001). Conclusion: Increased sternal uptake is significantly associated with CT structural abnormalities and knowledge of these non-neoplastic variants is essential for correct interpretation of SPECT/ CT bone scans especially in patients with known cancers.

Purpose: To identify the non-neoplastic variants of the sternal uptake in patients known to have a primary tumor, referred for detection of metastases elsewhere. Materials and methods: This retrospective study was approved by the Institutional Review Board. Fifty eligible patients (17 males & 33 females) known to have a primary tumor underwent 99mTc- MDP-bone scan for detection of metastases. All patients underwent SPECT/CT of the chest region. For each patient, 10 subsites were evaluated (right & left sternoclavicular joints, right and left first costo-sternal articulation, manubrium sterni, manubriosternal junction, body of the sternum, xiphisternal junction, xiphoid process and other sub-sites (e.g. chondro-sternal articulations)). The uptake was described as normal or abnormal. CT findings were categorized as normal/abnor- mal (arthritis, degenerative, developmental & congenital). Any patient with suspicious metastatic sternal lesion based on CT findings or abnormal tracer uptake was excluded. Results: A total of 500 sub-sites were analyzed. Increased uptake was seen in 189 sub-sites. Of them, 133 showed abnormal CT findings (95 arthritis, 33 degenerative, 3 developmental & 2 con- genital) and 56 sites were unremarkable. Of the 311 with normal uptake, only 18 showed abnormal CT findings (8 arthritis & 10 degenerative). The association was statistically significant (P 0.001). Conclusion: Increased sternal uptake is significantly associated with CT structural abnormalities and knowledge of these non-neoplastic variants is essential for correct interpretation of SPECT/ CT bone scans especially in patients with known cancers.

Purpose: To identify the non-neoplastic variants of the sternal uptake in patients known to have a primary tumor, referred for detection of metastases elsewhere. Materials and methods: This retrospective study was approved by the Institutional Review Board. Fifty eligible patients (17 males & 33 females) known to have a primary tumor underwent 99mTc- MDP-bone scan for detection of metastases. All patients underwent SPECT/CT of the chest region. For each patient, 10 subsites were evaluated (right & left sternoclavicular joints, right and left first costo-sternal articulation, manubrium sterni, manubriosternal junction, body of the sternum, xiphisternal junction, xiphoid process and other sub-sites (e.g. chondro-sternal articulations)). The uptake was described as normal or abnormal. CT findings were categorized as normal/abnor- mal (arthritis, degenerative, developmental & congenital). Any patient with suspicious metastatic sternal lesion based on CT findings or abnormal tracer uptake was excluded. Results: A total of 500 sub-sites were analyzed. Increased uptake was seen in 189 sub-sites. Of them, 133 showed abnormal CT findings (95 arthritis, 33 degenerative, 3 developmental & 2 con- genital) and 56 sites were unremarkable. Of the 311 with normal uptake, only 18 showed abnormal CT findings (8 arthritis & 10 degenerative). The association was statistically significant (P 0.001). Conclusion: Increased sternal uptake is significantly associated with CT structural abnormalities and knowledge of these non-neoplastic variants is essential for correct interpretation of SPECT/ CT bone scans especially in patients with known cancers.

Purpose: To evaluate the diagnostic performance of 18F-flurodeoxyglucose positron emission tomography/contrast enhanced computed tomography (18F-FDG PET/CT) in patients with clinically/radiologically suspected ovarian tumor recurrence and normal tumor markers. Materials and methods: A total of 54 18F-FDG PET/CT studies from 41 patients with sus- pected ovarian tumor recurrence and normal tumor markers were evaluated. Each patient underwent PET/CT with CE-CT scans in the same study. Studies were read independently by one experienced nuclear medicine physician and one experienced radiologist. A four- point score (score 0=definitely benign, score 1=probably benign, score 2=probably malignant and score 3 = definitely malignant) used to assess the presence or absence of recurrence (local, regional or distant). The final diagnosis of tumor status was made on the basis of subsequent follow-up by conventional imaging (CT/MRI), 18F-18F-FDG PET/CT or histopathology whenever possible. Results: Of the 54 studies evaluated, 26 (48%) studies had tumor recurrence and 28 (52%) studies were disease-free based on final diagnosis. Combined 18F-FDG PET/CT vs. CE-CT alone showed sensitivity, specificity and accuracy of 92% vs. 73%, 90% vs. 55%, and 91% vs. 63%, respectively. 18F-18F-FDG PET/CT was signifi- cantly more sensitive, more specific and more accurate compared to CE-CT with P-values of 0.06, 0.006 and 0.0001, respectively. Site-based analyses were also performed and showed significantly higher diagnostic indices for combined FDG-PET/CT. Conclusion: Combined 18F-FDG PET/CT with contrast enhancement is more accurate than CE-CT alone in the diagnosis of ovarian tumor recurrence in patients with normal tumor markers.

Objective: The purpose of the study was to evaluate the qualitative and semi- quantitative effects of using different low- dose computed tomography (CT) matrix sizes for attenuation correction of PET images. Methods: Co-registered 2-[F18]- fluoro-2-deoxy-D-glucose (FDG)-PET and CT images were acquired using a combined PET/CT scanner according to a standardized protocol. PET/CT reconstruction was repeated using default reconstruction protocols with different matrix sizes for low dose CT (512,768 and 1024) in 25 patients. The resulting images were analyzed qualitatively “image quality” and semi-quantitatively using “mean SUV & Signal to Noise Ratio (SNR)”. Results: No significant difference in the resulting attenuated corrected images reconstructed with the different matrix sizes either qualitatively or semi- quantitatively. Conclusion: The matrix size of the low dose CT used in the attenuation correction of PET images does not affect the image quality or semi-quantitative parameters.

Objectives: To assess efficiency of low dose 131Iin thyroid remnant ablation of patients with differentiated thyroid cancer after surgical treatment. Material and Methods: 88 patients with differentiated thyroid cancer, (age 20-75 years) tumor stage T1 to T3, with disease confined to the thyroid or cervical lymph nodes. All patients were treated with 131I after total thyroidectomy and pathologic lymph node resection, if present. A randomized double-armed prospective trial comparing low-dose [1110MBq (30mCi)] and high-dose [3700 MBq (100mCi)] radioiodine ablation.39 patients received low dose and 49 patients received high dose. Six months after the administration of radioiodine, measurements of TG, anti-TG antibodies together with neck ultrasound exam and 131Iwhole-body scan were performed. The success rate of ablation is determined by negative whole body 131I scan, negative neck ultrasonography and serum thyroglobulin level less than 2 ng/mL. Results: Successful ablation reported in 23 out of 39 cases (58.9 %) in the group receiving low-dose radioiodine [1110MBq] versus 37 out of 49 cases (75.5 %) in the group receiving the high dose [2960-3700 MBq] (P value= 0.098). A second follow up was performed one year after the ablative dose for the cases who had successive ablation from both groups. In the low dose group, only 12 out of 23 patients (52%) were available, all of them didn't show any disease recurrence, versus 17 cases out of 37 in the high dose group, 16/17 patients didn't had recurrence, while in one case there was a recurrent disease at the thyroid bed. Conclusion: From this ongoing data, non-significant higher success thyroid remnant ablation was recorded for high compared to low radioiodine doses.

Objectives: To evaluate the diagnostic performance of 18F-Flurodeoxyglucose positron emission tomography/ computed tomography in comparison to contrast enhanced computed tomography alone in the detection of peritoneal metastases after initial treatment of malignant ovarian tumors. Patients and Methods: The study prospectively recruited 111 patients with clinical suspicion of ovarian tumor recurrence. Each patient underwent 18FFDG PET/CT and Ce-CT scans in the same day. Study-based analyses for a total of 136 scans were evaluated. Studies were read independently by one experienced nuclear medicine physician and one experienced radiologist. A four-point score (score 0= definitely benign, score 1 = probably benign, score 2= probably malignant and score 3= definitely malignant) used to assess the presence or absence of peritoneal metastases. The final diagnosis of peritoneal disease status was made on the basis of subsequent follow-up by 18F-FDG PET/CT, conventional imaging (CT/MRI) or histopathology whenever possible. Results: Of the 136 studies evaluated, 75 (55%) studies had peritoneal disease and 61 (45%) studies were free based on final diagnosis.18F-FDG PET/CT & Ce-CT had sensitivity, specificity and accuracy of 96% vs 69%, 100% vs 85%, and 98% vs 76%; respectively. 18F-FDG PET/CT was significantly more sensitive, specific and accurate compared to Ce-CT with P-values of 0.0001, 0.004 and 0.0001; respectively. Conclusions: 18F-FDG PET/CT is superior to Ce-CT in the diagnosis of peritoneal metastases in patients with malignant ovarian tumors.

Objectives: To evaluate the diagnostic performance of 18F-flurodeoxyglucose positron emission tomography/ computed tomography in patients with suspected biochemical ovarian tumor recurrence in comparison to contrast enhanced CT. Patients and Methods: A total of 64 18FFDG PET/CT studies for patients with biochemical suspicious ovarian tumor recurrence were evaluated. Each patient underwent 18F-FDG PET/CT and Ce-CT scans in the same day. Studies were read independently by one experienced nuclear medicine physician and one experienced radiologist. A four-point score (score 0 = definitely benign, score 1 = probably benign, score 2 = probably malignant and score 3 = definitely malignant) used to assess the presence or absence of recurrence (local, regional or distant). The final diagnosis of tumor status was made on the basis of subsequent followup by 18F-FDG PET/CT, conventional imaging (CT/MRI) or histopathology whenever possible. Results: Of the 64 studies evaluated, 61 (95%) studies had tumor recurrence and 3 (5%) studies were free based on final diagnosis. 18F-FDG PET/CT & Ce-CT had sensitivity 97% vs. 87%, specificity 100% vs. 33%, and accuracy of ( 97% vs. 84% ) respectively. 18F-FDG PET/CT was significantly more sensitive and more accurate compared to Ce-CT with P-value of 0.07 and 0.02; respectively with no statistical significant difference in accuracy.Conclusions: 18FFDG PET/CT is more accurate than Ce- CT in the diagnosis of ovarian tumor recurrence in patients with elevated tumor marker.

Background: Thyroglobulin is commonly used to monitor patients with differentiated cancer thyroid. It has also become an excellent biological marker for tumor persistence or recurrence.Aim of study: To study the relation between the level of baseline serum thyroglobulin (TG) and thyroid remnant ablation outcome using radioactive iodine-131 (RAI-131) in patients with differentiated thyroid cancer after surgical treatment. Methods: A prospective study involved 64 patients (age 20-77 years) with differentiated thyroid cancer, referred for post-surgical 131I ablation. All patients performed baseline serum TG, anti-TG-Ab's under TSH stimulation as well as neck ultrasonography, before receiving RAI-131ablation dose 1110 - 3700 MBq (30 -100 mCi). Follow-up was performed 6-8 months later. Successful ablation was determined by negative whole body 131I scan, negative neck ultrasonography and stimulated serum thyroglobulin level less than 2 ng/mL. Results: Successful ablation was reported in 38 out of 64 cases (59.4 %). Baseline serum thyroglobulin level was significantly predictive of ablation outcome. ROC analysis showed AUC (area under curve) of 0.66 (CI: 0.53 - 0.78; P = 0.03). A cutoff value of 4.4 ng/ml showed sensitivity of 79 % and specificity of 68% in predicting ablation outcome. Patients were divided into high (n = 32) and low (n = 32) baseline TG groups using this cut-off point. Successful ablation significantly higher in low TG group (25/32 vs. 13/32; P = 0.002). There was no significant difference between the two groups regarding their clinical and pathological data. Conclusion: Baseline serum thyroglobulin is associated with ablation outcome. Serum TG> 4.4 is linked to significantly higher rates of unsuccessful ablation.