Inveon research workplace software irw 4

Magnetic resonance imaging (MRI) data were analyzed using MicroView (GE Healthcare). [¹⁸F]FAZA and [¹⁸F]FLT-PET were each co-registered semi-automatically using the semi-rigid co-registration tool to corresponding CT datasets, and tumor and muscle regions of interest (ROIs) were drawn and analyzed using the Inveon Research Workplace software (IRW 4.0, Siemens). Representative CT- and MRI-based ROIs are shown in Suppl. Fig. S2 (see ESM). For the hypoxic fraction analysis (number of hypoxic tumor voxels over number of total tumor voxels), a voxel was classified to be hypoxic if its [¹⁸F]FAZA-PET signal was higher than an animal-specific threshold. This threshold was defined as the mean + 3 standard deviations of the [¹⁸F]FAZA-PET signal value measured in the muscle region of the same animal [21 ]. The same quantification method was used to assess the fraction of [¹⁸F]FLT-positive voxels within a tumor.

The PET and CT datasets were registered, contoured, and analyzed using the Inveon Research Workplace software (IRW 4.0, Siemens). The hypoxic fraction is defined as the number of tumor voxels with FAZA-PET signal values above a set threshold over the total number of tumor voxels. The hypoxia signal threshold value was defined as the mean FAZA-PET signal value measured in the upper leg muscle of the same mouse + 3 standard deviations [31 (link)].