Radiation dosimetry of [18F]GP1 for imaging activated glycoprotein IIb/IIIa receptors with positron emission tomography in patients with acute thromboembolism.

PURPOSE: 4-(3S)-3-[5-(2-[18F]-fluoroethoxy)pyridin-3-yl]-3-[({(3R)-1-[3-(piperidin-4-yl)propanoyl]-piperidin-3-yl}carbonyl)amino]propanoic acid ([18F]GP1) is a radiotracer developed for targeted imaging of activated platelet glycoprotein IIb/IIIa receptors with positron emission tomography/computed tomography (PET/CT) in acute thromboembolism. We evaluated here radiation dosimetry of [18F]GP1 in humans. PROCEDURES: We studied 30 subjects (10 with deep vein thrombosis, 10 with pulmonary embolism, and 10 with arterial thromboembolism) who had signs or symptoms of acute thromboembolism, and were confirmed to have thromboembolic foci by imaging studies. Dynamic whole-body PET/CT images were acquired for up to 140 min after injection of 250 MBq of [18F]GP1. Radiation absorbed dose and effective dose were calculated using the OLINDA/EXM software. RESULTS: [18F]GP1 PET images showed high initial uptake of the tracer in the heart, spleen, kidney, and liver. [18F]GP1 activity was cleared by hepatobiliary and urinary excretion. The organ receiving the highest radiation absorbed dose (mGy/MBq) was the urinary bladder (0.0884 ±â€¯0.0458), followed by upper large intestine (0.0498 ±â€¯0.0189), small intestine (0.0454 ±â€¯0.0166), and kidneys (0.0350 ±â€¯0.0231). The effective dose (mSv/MBq) was 0.0212 ±â€¯0.0027 (ICRP 103). ED was not significantly different between the three disease groups (p = 0.94). A 45-minute voiding reduced the urinary bladder wall radiation dose to 0.0495 ±â€¯0.0140 mGy/MBq, and effective dose (ICRP 103) to 0.0186 ±â€¯0.0030. CONCLUSIONS: [18F]GP1 has favorable radiation dosimetry profile for clinical PET/CT imaging. The ED is comparable to commonly used 18F PET tracers.

Metabolic tumor volume and total lesion glycolysis predict tumor progression and survival after salvage surgery for recurrent oral cavity squamous cell carcinoma.

BACKGROUND: This study evaluated the prognostic role of Fluorine 18-fluorodeoxyglucose positron emission tomography/CT (18 F-FDG PET/CT) parameters quantitatively measured in patients with recurrent oral cavity cancer. METHODS: Cox proportional hazards regression analyses were used to assess the associations between quantitative 18 F-FDG PET/CT parameters and other clinicopathological factors and progression-free survival (PFS) and overall survival (OS). RESULTS: All of the 18 F-FDG PET parameters (SUVmax , SUVmean , SUVpeak , metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) were significantly associated with poor PFS and OS outcomes after salvage treatment (P < .01). In multivariate analyses, Karnofsky performance score, recurrence site, MTV, and TLG were independent variables predictive of both PFS and OS (P < .05). High MTV (>8.8 mL) or TLG (>29.4 g) values at recurrent lesions were associated with >5-fold increased risk for tumor progression and mortality after salvage surgery. CONCLUSIONS: The PET parameters of MTV and TLG measured at recurrent lesions may predict tumor progression and survival after salvage treatment. CONDENSED ABSTRACT: This study examined the role of 18 F-FDG PET/CT at recurrent staging for predicting tumor progression and survival in 71 consecutive patients with recurrent oral cavity squamous cell carcinomas. Of 18 F-FDG parameters, metabolic tumor volume and total lesion glycolysis were independent factors predictive of tumor progression and survival after salvage treatment.