Inveon animal pet scanner

[⁸⁹Zr]Zr
radio-labeled and purified peptide 19 (5 MBq corresponding
to 1 nmol) in 200 μL was injected intravenously in the tail
vein of rats (n = 6). Animals were imaged at 4, 8,
24, and 72 h after injection for 15 min (4 and 8 h), 20 min (24 h),
or 30 min (72 h), using an Inveon animal PET scanner (Siemens Preclinical
Solutions). Reconstruction of scans was performed using Inveon Acquisition
Workplace software with an iterative 3D ordered subset expectation
maximization using maximum a priori with shifted Poisson distribution
algorithm with the following parameters: matrix, 256 × 256 ×
161; pixel size, 0.4 mm × 0.4 mm × 0.8 mm with a corresponding
beta of 0.05 mm. Animals were euthanized by CO₂ asphyxiation
at 24 h (n = 3) and 72 h (n = 3)
after injection, and, subsequently, blood, muscle, lung, spleen, liver,
bone marrow, kidney, brain, and pancreas were collected for quantification
of the radioactive signal using a gamma counter (Wizard, PerkinElmer)
and expressed as the percentage of injected dose per gram tissue (%ID/g),
calculated from the amount of radioactivity measured in aliquots of
the injected dose.

[⁸⁹Zr]Zr radio-labeled and purified peptides 13 and 18 were adjusted with non-radio-labeled peptide and vehicle
to 1 nmol/200 μL. Each animal (n = 6 per peptide)
was injected with 1 nmol (4–6 MBq) in 200 μL vehicle
through an intravenous tail vein injection. At 4 and 24 h after injection,
under general anesthesia or after CO₂ asphyxiation, respectively,
animals were imaged for 30 min using an Inveon animal PET scanner
(Siemens Preclinical Solutions). Reconstruction of scans was performed
using Inveon Acquisition Workplace software with an iterative three-dimensional
(3D) ordered subset expectation maximization using maximum a priori
with shifted Poisson distribution algorithm with the following parameters:
matrix, 256 × 256 × 161; pixel size, 0.4 mm × 0.4 mm
× 0.8 mm with a corresponding beta of 0.05 mm. After imaging
at 24 h post-injection, blood, muscle, lung, spleen, liver, bone marrow,
kidney, brain, and pancreas were collected for quantification of the
radioactive signal using a gamma counter (Wizard, PerkinElmer) and
expressed as the percentage of injected dose per gram tissue (%ID/g),
calculated from the amount of radioactivity measured in aliquots of
the injected dose.