First of all, I discovered RadiAnt this afternoon after looking at various non-MAC DICOM viewers and I'm absolutely amazed! I'm seriously considering introducing this to our nuclear medicine department.

I'm still having a problem though. I have a large dynamic PET serie of 3750 files which should be divided in 150 slide scans (25 scans at different times total). This is declared in the DICOM tags as [(0054,0081),US, 'Number of Slices', 150] and [(0054,0101),US, 'Number of Time Slices', 25]. RadiAnt doesn't recognize this though and displays the serie as being 3750 images long. I want to use the time-intensity curve for these 25 scans.
Does anyone know how I can solve this problem with the current version?

First of all, congratulations on your discovery :-)
I'm afraid that currently there is no easy way to get the TIC curve for your study...
In future versions RadiAnt will be able to split such multi-series into parts.
The only way with the current version is to open your large series in 25 panels (CTRL + click on a thumbnail), disable synchronization and scroll manually in each panel to show the same image in subsequent series. Then you can draw your ROI and duplicate it in other panels and finally use the TIC tool...

Please check our latest beta version, hopefully it solves your problem :-)
http://www.radiantviewer.com/startdownload.php?f=beta