Evaluation of PET Scanner Performance in PET/MR and PET/CT Systems: NEMA Tests.

OBJECTIVE: The aim of the present study was to compare the performance of positron emission tomography (PET) component of PET/computed tomography (CT) with new emerging PET/magnetic resonance (MR) of the same vendor. METHODS: According to National Electrical Manufacturers Association NU2-07, five separate experimental tests were performed to evaluate the performance of PET scanner of General Electric GE company; SIGNATM model PET/MR and GE Discovery 710 model PET/CT. The main investigated aspects were spatial resolution, sensitivity, scatter fraction, count rate performance, image quality, count loss and random events correction accuracy. RESULTS: The findings of this study demonstrated superior sensitivity (~ 4 folds) of PET scanner in PET/MR compared to PET/CT system. Image quality test exhibited higher contrast in PET/MR (~ 9%) compared with PET/CT. The scatter fraction of PET/MR was 43.4% at noise equivalent count rate (NECR) peak of 218 kcps and the corresponding activity concentration was 17.7 kBq/cc. Whereas the scatter fraction of PET/CT was found as 39.2% at NECR peak of 72 kcps and activity concentration of 24.3 kBq/cc. The percentage error of the random event correction accuracy was 3.4% and 3.1% in PET/MR and PET/CT, respectively. CONCLUSION: It was concluded that PET/MR system is about 4 times more sensitive than PET/CT, and the contrast of hot lesions in PET/MR was ~ 9% higher than PET/CT. These outcomes also emphasize the possibility to achieve excellent clinical PET images with low administered dose and/or a short acquisition time in PET/MR.

Reconstruction of lower extremity primary malignant and metastatic bone tumours with modular endoprosthesis.

INTRODUCTION: This study is aimed to assess the functional results of cases with lower extremity malignant and metastatic bone tumours that were treated with modular tumour resection prostheses. MATERIALS AND METHODS: 49 patients were retrospectively examined. 27 (55.1%) patients had a primary bone tumour, and 22 (44.9%) had a metastatic bone tumour. Although most tumours located in the proximal femur were metastatic, tumours located around the knee were mostly primary malignant bone tumours. The functional assessments of our patients were made according to the Musculoskeletal Tumour Society (MSTS) scoring system. The Student's t-test and the Chi-square test were used for statistical analyses. RESULTS: 30 (61.2%) of the patients were men, and 19 (38.8%) were women. The average age was 46.2 ± 1.9 years. Tumours were located in the proximal femur in 27 (55.1%) patients, distal femur in 16 (32.7%) patients and proximal tibia in 6 (12.2%) patients. 14 (28.6%) patients had a pathological fracture on admission. The average follow-up period of our patients was 27.4 ± 3.4 months, and the average MSTS score was 74.3 ± 13%. Complications developed at any time in 34.7% of the patients, and the most common symptoms were aseptic loosening (8.2%) and prosthesis infection (8.2%). Local relapse was found in one (2%) patient. The 5-year survival rate was 68.3% in patients with a primary tumour and 30% in patients with a metastatic tumour. CONCLUSION: Although endoprosthesis reconstruction had advantages of giving very good functional results in the early phases, it was found to cause mechanical complications, especially in patients with primary bone tumours during the mid and late phases.

The impact of fasting during Ramadan on the glycemic control of patients with type 2 diabetes mellitus.

BACKGROUND: Millions of Muslims fast from dawn until dusk during the annual Islamic holy month of Ramadan. Most of the studies evaluating biochemical changes in diabetic patients during Ramadan showed little changes in the glycemic control. In this study, our aim was to assess the impact of fasting during Ramadan on glycemic control in patients with type 2 diabetes. METHODS AND DESIGN: We examined 122 patients with type 2 diabetes (82 female, 40 male, age 56.93 ± 9.57 years) before and after the Ramadan. 66.4% of the patients were treated with oral antidiabetic (OAD) alone, 6.5% with a combination of insulin plus OAD and 19.7% with insulin alone. 88 of 122 patients fasted during Ramadan (26.98 ± 5.93 days). Weight, body mass index (BMI), waist circumference, blood pressure, fasting plasma glucose (FPG), postprandial glucose (PPG), fructosamine, HbA1c, fasting insulin and lipid parameters were measured. RESULTS: The frequencies of both severe hyperglycemia and hypoglycemia were higher in the fasting group, but the difference was not significant (p=0.18). Weight, BMI, waist circumference, blood pressure, FPG (143.38 ± 52.04 vs. 139.31 ± 43.47 mg/dl) PPG (213.40 ± 98.56 vs. 215.66+109.31 mg/dl), fructosamine (314.18 ± 75.40 vs. 314.49 ± 68.36 µmol/l), HbA1c (6.33 ± 0.98 vs. 6.22 ± 0.92%) and fasting insulin (12.61 ± 8.94 vs. 10.51 ± 6.26 µU/ml) were unchanged in patients who fasted during Ramadan. Microalbuminuria significantly decreased during Ramadan (132.85 ± 197.11 vs. 45.03 ± 73.11 mg/dl). CONCLUSIONS: In this study, we concluded that fasting during Ramadan did not worsen the glycemic control of patients with type 2 diabetes.