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

Demir, M | Toklu, T | Abuqbeitah, M | Cetin, H | Sezgin, HS | Yeyin, N | Sonmezoglu, K

Article | 2018 | MOLECULAR IMAGING AND RADIONUCLIDE THERAPY27 ( 1 ) , pp.10 - 18

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 acc . . .uracy. Results: The findings of this study demonstrated superior sensitivity (similar to 4 folds) of PET scanner in PET/MR compared to PET/CT system. Image quality test exhibited higher contrast in PET/MR (similar to 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 similar to 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 Daha fazlası Daha az


Demirci, E | Toklu, T | Yeyin, N | Ocak, M | Alan-Selcuk, N | Araman, A | Kabasakal, L

Article | 2018 | RADIATION PROTECTION DOSIMETRY182 ( 4 ) , pp.518 - 524

Ga-68-PSMA-11PET/CT has been proven to have high clinical value for imaging of prostate cancer and rapidly gained popularity. In this study, we aimed to investigate absorbed doses of Ga-68-PSMA-11. Seven patients (mean age = 66.9 +/- 6.6 years, range: 57-79 years) were enrolled in the study. Whole body PET images were acquired with multiple time points. MIRD method, NUKFIT and OLINDA/EXM software were used for dosimetry calculations. Kidneys, bladder wall, salivary and lacrimal glands received the highest absorbed dose. Estimated absorbed doses to these organs after injection of 150 MBq Ga-68-PSMA-11 were 37.0, 12.6, 14.4 and 6.3 mS . . .v, respectively. Effective dose from PET scanning with 150 MBq injected Ga-68-PSMA-11 was 2.5 mSv. In conclusion, Ga-68-PSMA- 11 has a favorable dosimetry profile similar to the Ga-68 labeled octreotide analogs, which are used safely in routine clinical practices for many years. No adverse effects were reported. The kidneys were the dose-limiting organs Daha fazlası Daha az

Lu-177-DOTATATE therapy in patients with neuroendocrine tumours including high-grade (WHO G3) neuroendocrine tumours: response to treatment and long-term survival update

Demirci, E | Kabasakal, L | Toklu, T | Ocak, M | Sahin, OE | Alan-Selcuk, N | Araman, A

Article | 2018 | NUCLEAR MEDICINE COMMUNICATIONS39 ( 8 ) , pp.789 - 796

Purpose Upon diagnosis, distant metastases are encountered in 21-50% of neuroendocrine tumours (NETs). However, few systemic treatment options are available for the well-differentiated NETs in the metastatic stage. Lu-177-DOTATATE is one of the most effective treatments in this limited patient group. We retrospectively investigated its efficacy and effect on the survival in patients with both well-differentiated and grade III NETs who had high uptake in pretherapeutic Ga-68-DOTATATE PET/computed tomography scans. Patients and methods Patients with metastatic NETs treated with Lu-177-DOTATATE between January 2010 and November 2015 in . . . our department were included in this retrospective cohort. Toxicity and adverse effects were evaluated according to SWOG criteria. Progression-free survival (PFS) and overall survival (OS) rates were calculated considering the first date of treatment. Response was evaluated according to RECIST criteria. Potential predictors of survival and response were analysed. Results Patients (n=186) with metastatic NETs originating from various primary sites (bronchial, pancreatic, nonpancreatic gastroenteropancreatic-NETs, pheochromocytoma-paraganglioma and unknown primary) were treated with 1107 courses of Lu-177-DOTATATE treatment (median: 6; range: 3-12). Among 160 patients whose responses to treatment could be evaluated according to the RECIST criteria, 28.1% (n=45) had a progressive disease, 21.9% (n=35) had a stable disease, 46.9% (n=75) had a partial response and 3.1% (n=5) had a complete response. Median follow-up was 30.6 months. The Kaplan-Meier estimated median PFS was 36.4 months, mean PFS was 38 months and the mean OS was 55 months. The disease control rates in patients with WHO grades I, II and III were 74, 73 and 60%, respectively, and the OS rates were 61.9, 52.2 and 38.4 months, respectively. We observed no major renal toxicity except a minor increase (11.1%) in average serum creatinine levels. In 33.9% (n=56) of the patients, grade I toxicity; in 9.1% (n=15), grade II; and in 1.2% (n=2), grade III toxicity were observed. Conclusion Lu-177-DOTATATE therapy is an important treatment option in somatostatin receptor type-2-positive pancreatic, nonpancreatic gastroenteropancreatic-NETs, and lung NETs including metastatic NETs with an unknown primary site and significantly contributed to patients' OS. Additionally, peptide receptor radionuclide therapy may have a role in a selected subgroup of patients with grade III NET with high somatostatin receptor type-2 expression Daha fazlası Daha az

Determination of Radiation Dose in 177Lu-DOTATATE Treatment with 99m-Tc-HYNICTATE Scintigraphy

Yeyin, N | Toklu, T | Aygun, A | Karayel, E | Pehlivanoglu, H | Demirci, E | Kabasakal, L


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