Pmod analysis software

Rat femurs from the various demographics were thawed and rehydrated in 1X PBS solution for 10 min before scanning and imaged using ultrahigh-resolution micro-CT imaging (OI/CT, MILabs, Utrecht, Netherlands) for additional skeletal phenotyping. Images were acquired at a voltage of 50 kV, a current of 0.21 mA, and an exposure time of 75 ms. Subsequently, projections were reconstructed using vendor software and converted to DICOM (Digital Imaging and Communications in Medicine) files using PMOD analysis software (PMOD Technologies LLC, Zurich, Switzerland) at a voxel size of 20 μm. Quantification of bone parameters was performed using Imalytics Preclinical (Gremse-IT GmbH, Aachen, Germany). Distal metaphysis of femur specimens was analyzed using a spherical region of interest (ROI) 3 mm in diameter, positioned in the trabecular area. The trabecular analysis included the acquisition of bone volume (BV, mm³), bone volume fraction (BV/TV %), trabecular thickness (Tb.Th, mm), and trabecular separation (Tb.Sp mm). BV (mm³) in cortical bone in the mid-diaphysis was analyzed using a cylindrical ROI 6 mm ⌀ by 2 mm in length.

Dispersion of the NaGdF₄:Yb³⁺/Er³⁺@PEG-¹²⁵I nanoparticles in PBS buffer (200 µl; 30 MBq/mouse) was intravenously injected into two mice via the tail vein. ¹²⁵I with a long half-life (59.49 days) was selected as a radioisotope because it is cheap, easily available on the market, readily chemically modifiable, and very suitable especially for small-animal SPECT with an Albira imaging system used in our work. The low-energy emission (35 keV) of ¹²⁵I is also a great advantage for the longitudinal studies. Biodistribution of the particles in mice was evaluated under anesthesia (2% isoflurane in air); both mice were scanned at 30, 50, 70, and 260 min and 1, 2, 6, and 8 days after the injection and acquisitions were obtained using multi-pinhole collimators. Acquisition time was 45 min (90 s/projection) and followed by a single CT scan (15 min). Image analysis and co-registration was done using PMOD analysis software (PMOD Technologies; Zürich, Switzerland).