No abstract

No abstract

No abstract

The present study estimated the biodistribution and radiationabsorbed dose of epidermal growth factor receptor (EGFR) radioligand 11 C-PD153035 in whole-body PET examinations of healthy volunteers. Methods: Two-dimensional whole-body PET was performed on 9 subjects after injection of 11 C-PD153035 at 329.3 6 77.8 MBq (mean 6 SD). A total of 12 frames were acquired for approximately 90 min in 7 segments of the body. Regions of interest were drawn on PET images of source organs. Residence time was calculated as the area under the timeactivity curve. Radiation dosimetry was calculated from organ residence time by use of MIRDOSE3 software. Results: The renal and hepatobiliary systems played important roles in 11 C-PD153035 excretion from the body, accounting for the excretion of approximately 23% and 19% of the injected radioactivity, respectively. Blood-pool activity was only moderate and declined over time. Tracer accumulation in the lungs, bone marrow, and muscles was slight, resulting in low background activity in the chest. The organs with the highest radiation-absorbed doses were the urinary bladder and the gallbladder; the effective doses were 6.08E202 6 1.85E202 and 2.40E202 6 8.01E203 mGy/ MBq, respectively. The effective dose equivalent was 7.43E203 6 1.10E203 mSv/MBq, and the dose-limiting organ was the urinary bladder. Conclusion: On the basis of the estimated absorbed dose, 11 C-PD153035 displayed a favorable radiation dose profile in humans and therefore could be used in multiple PET examinations of the same subject per year. 11 C-PD153035 is a promising ligand for the investigation of EGFR in humans, especially in chest tumors such as non-small cell lung cancer.

No abstract

The purpose of this study was to evaluate hypoxia in esophageal squamous cell carcinoma (SCC) with (18)F-fluoroerythronitroimidazole positron emission tomography/computed tomography ((18)F-FETNIM PET/CT). We determined an imaging threshold for hypoxia, quantified the spatiotemporal variability of hypoxia in untreated tumor, and evaluated the ability of (18)F-FETNIM PET to predict clinical response following concurrent chemoradiotherapy (CCRT). Twenty-eight consecutive patients with inoperable SCC of the esophagus were consecutively accrued between April 2007 and June 2010. The first 10 patients received two pretreatment (18)F-FETNIM PET/CT scans on separate days. The remaining 18 patients only underwent (18)F-FETNIM PET/CT once before CCRT. The ratio of the maximum standardized uptake value (SUV(max) ) of 336 normal tissue regions (i.e. heart, lung, brain, or muscle) to the mean standardized uptake value (SUV(mean)) of the respective patient's spleen was calculated, and the imaging threshold for hypoxia defined as the level of uptake demonstrated by less than 5% of tissue regions. Among the patients with two pretreatment scans, each pair of scans was compared with respect to location and intensity of uptake to assess for baseline spatiotemporal variability. Logistic regression analysis was used to determine whether pretreatment imaging characteristics are predictive of clinical response. The mean and median ratios of the SUV(max) of tissue : SUV(mean) of spleen were nearly identical, and 95% of the ratios fell below 1.3. The mean Dice similarity coefficient for the hypoxic volumes on pretreatment PET scans acquired in the same patient on different days was 0.12 (range, 0.05-0.21). Individuals' tumor SUV(max) and SUV(mean) did not vary significantly, but on average, the geometric centers of hypoxic regions shifted 15 mm (range, 8-20 mm) from the first pretreatment scan to the second. SUV(max) was the imaging characteristic most predictive of treatment response (P= 0.041), with high SUVmax associated with poor clinical response. (18)F-FETNIM PET/CT can depict hypoxia in esophageal SCC. Prior to CCRT, tumor hypoxia demonstrates spatial variability on different days, although overall (18)F-FETNIM uptake remains similar. Baseline SUV(max) may be predictive of treatment response.

The aim of the present study was to investigate the biodistribution of

No abstract