Inveon small animal pet computed tomography scanner

On one day after AMI induction, the animals were scanned on the Inveon small-animal PET/computed tomography (CT) scanner (Siemens) in three-dimensional acquisition mode. After the intravenous injection of [¹⁸F]FP-DPAZn2 (2.4∼3.7 MBq, 300∼400 μCi/Kg), the rats were anesthetized via the intraperitoneal injection of 2% pentobarbital (40 mg/kg), and PET images were obtained at four time points (30, 60, 90 and 120 min) post-injection. The CT scan was used for the attenuation correction and localization of the lesion site. Images were reconstructed by the two-dimensional ordered-subsets expectation maximum (OSEM). For the small-animal PET scan, regions of interest (ROIs) were drawn over the heart on the decay-corrected whole-body coronal images using the Inveon Research Workplace 4.1 software. The radioactivity concentration (i.e., accumulation) in the heart was obtained from the mean pixel value within the multiple ROI volume, which was converted to MBq/mL using a conversion factor. Assuming the density of tissue was 1 g/cm³, the ROIs were converted to MBq/g and then divided by the administered activity to obtain an imaging ROI-derived % ID/g [29 (link)]. After PET-CT imaging, the blood was collected, the tissues of the heart were excised and weighted, and the radioactivities of these tissues were measured with the gamma counter.

In vivo PET imaging experiments were using the Inveon small-animal PET/computed tomography (CT) scanner (Siemens). Those allografted nude mice, treated and untreated, were imaged by PET/CT scanner after injection of 0.2 mL ¹⁸F-ML-8 solution (3.7–7.4 MBq, 100–200 μCi) via tail vein, after the mice were anesthetized with 5% chloral hydrate solution (6 mL/kg) and placed on a heating pad to warm the animal throughout the scanning. Imaging started with a low-dose CT scan, which was followed by a ten-minute PET scan. Ten-minute static PET images were acquired at four time points (30, 60, 90, and 120 min) after intravenous injection. The CT scan was used for attenuation correction and localization of the lesion site. Images were reconstructed by two-dimensional ordered-subsets expectation maximum (OSEM). For small-animal PET scan, regions of interest (ROIs) were drawn over the tumor and major organs on decay-corrected whole-body coronal images using Inevon Research Workplace 4.1 software. Radioactivity concentration (i.e., accumulation) of tumor or organs was obtained from the mean pixel values within the multiple ROI volume, which was converted into MBq/mL using a conversion factor. Assuming the density of tissue was 1 g/cm³, the ROIs were converted to MBq/g and then divided by the administered activity to obtain an imaging ROI-derived % ID/g.

PET imaging of tumor-bearing mice was carried out using the Inveon small animal PET/computed tomography (CT) scanner (Siemens). 3.7 MBq (100 μCi) of ¹⁸F-FP-PEG₂-β-Glu-RGD₂ was injected intravenously in conscious animals via the tail vein. A few minutes later the mice were anesthetized with 5% chloral hydrate solution (6 mL/kg). Ten-minute static PET images were acquired at four time points (30, 60, 90, and 120 min) postinjection. The images were reconstructed by two-dimensional ordered-subset expectation maximum (OSEM). For the integrin receptor-blocking experiment, RGD (4 mg/kg) was injected with 3.7 MBq of ¹⁸F-FP-PEG₂-β-Glu-RGD₂ into PC-3 tumor-bearing mice (n = 4). At 1 h after injection, the 10-min static microPET scans were acquired. For each microPET scan, regions of interest (ROIs) were drawn over the tumor, normal tissue, and major organs on decay-corrected whole-body coronal images using Inevon Research Workplace 4.1 software. The maximum radioactivity concentration (accumulation) within a tumor or an organ was obtained from mean pixel values within the multiple ROI volume, which was converted to MBq/mL/min by using a conversion factor. Assuming a tissue density of 1 g/mL, the ROIs were converted to MBq/g/min and then divided by the administered activity to obtain an imaging ROI-derived %ID/g. The mice were sacrificed at the end of the study for PET imaging.