Abstract
1449
Objectives: To evaluate the ability of fluorine-18 flurorerythronitroimidazole(18F-FETNIM) in detecting hypoxia and re-oxygenation in vivo after X-ray irradiation. Methods: 45 BALB/c nude mice were xenografted with SPCA-1, human lung adenocarcinoma cell, and tumors were grown to a weight of 0.26-5.82g and divided into three groups. These mice were undergone 0Gy, 10Gy, and 20Gy X-ray irradiation respectively. The levels of intratumoral PO2 were measured with polar graphic oxygen needle probe pre- and post irradiation. 18F-FETNIM was then injected intravenously 3h later and every three mice were killed at 30min, 60min, 120min and 180min, respectively. Biodistribution of 18F-FETNIM was studied. The tissues of tumor, blood and muscle were picked-up, weighed and the radioactivity was measured with γ-counting well, and then the ID%/g was counted. Tumor-to-muscle (T/M) and tumor-to-blood (T/B) ratio were calculated. The character of tumor was observed by H&E stain. And the images of last three mice were obtained with PET/CT after one and two hours. Results: 1. In control group, the uptake of 18F-FETNIM in the tumor was gradually decreased within 3h, while the T/M increased and reached a peak at 2h, then decreased gradually. 2. In irradiation group, the uptake was significantly higher than those in control group (F=19.50, P<0.05), but there was no significant difference betweew 10Gy and 20Gy group(F=6.29, P>0.05). The T/M and T/B increased until 3h and the uptake were higher than in control group(F=43.47, P<0.05). 3. Intratumoral pO2 measurement of the SPCA-1 cell tumor indicated that tumor oxygen tension ranged from 0.28 to 30.45 mmHg. Normal muscle oxygen tension ranged 30.2-40.5 mmHg. The intratumorl temperature was also measured. The temperature ranged from 16.39°C -30.30°C and increased as the tumor hypoxic tension increased. In irradiation group, the re-oxygenation was found at 2h after irradiation. 4. Hot spot of 18F-FETNIM at tumor site was observed in all mice 1h post injection, and the spot became more clear at 2h. Conclusions: Retention of 18F-FETNIM in tumor tissue is increased and clearance is decreased. When exposed to X-ray, the ratios of T/M and T/B were also increased, indicating that 18F-FETNIM could be applied to detect the re-oxygenation of tumor in certain degree.
- Society of Nuclear Medicine, Inc.