AMIDE (Amides a Medical Imaging Data Examiner) is a competely free tool for viewing, analyzing, and registering volumetric medical imaging data sets. It's been written on top of GTK+, and runs on any system that supports this toolkit (Linux, Windows, Mac OS X, etc.).

AMIDE Features:
1. Abitrary orientation, thickness, and time period slice viewing of a data set.
2. Multiple data sets can be loaded and viewed at once, with either linked or fused views. Each data set can be viewed from any orientation. Fusing can be done by blending or overlay.
3. Nearest Neighbor and Trilinear interpolation functions
4. Zooming
5. The following colormaps are supported: Black/White,White/Black,Red/Green/Blue Temperature, Hot Metal/Blue/Green, Spectrum, NIH/UCLA
6. Thresholding: data sets are thresholded independently. Data sets can be thresholded over the entire data set or over each slice.
7. 3-dimensional ROI's can be drawn directly on the images and statistics can be generated for these ROI's. Currently supported ROI's are ellipsoids, elliptic cylinder's, boxes, and isocontours.
8. Imports raw data files (8bit,16bit,32bit,float,etc). Also imports Acr/Nema 2.0, Analyze (SPM), DICOM 3.0, InterFile3.3, ECAT 6/7, and Gif87a/89a (using the (X)medcon/libmdc).
9. Imports most clinical DICOM files (using the DCMTK library).
10. Allows cropping and clearing regions of data sets.
11. Anisotropic filtering wizard. Current filters: Gaussian, 1D Median, and 3D Median
12. Saves studies (ROI and Data Set data) as XML data.
13. Series of slices can be viewed.
14. Fly through movies can be generated as MPEG1 files
15. True volume rendering support with the capability of rendering multiple data sets at a time. Series of renderings can be saved as MPEG1 movies. Data sets can also be rendered as stereoscopic image pairs
16. Alignment of data sets is supported using fiducial markers. This is done by placing fiducial reference points on the data sets to be aligned, and then running an alignment wizard to perform a rigid body transformation (procrustes method).
17. A profile tool is included that can calculate gaussian fits and FWHM's of the generated line profiles. Profiles can also be saved for external use.

The license of this software is Free, you can free download and free use this graphing software.