About Attenuation Image

Dear CASToR users,

I am running a 3D voxelized brain phantom simulation with GATE, and I want to have attenuation correction in the castor-recon for my reconstructed image. I read some information in castor documentation and archive that indicates the only thing I need is an attenuation image which is used for calculating attenuation factor during sensitivity image calculation. So does anyone know how to directly derive the voxelized phantom attenuation image?



Building the attenuation image is a task independent from CASToR, except for the format and the unit. How did you build your brain phantom? If you used some phantoms already available on the internet, usually there is either an attenuation image, or a label image saying which kinds of tissues compose each voxel and attenuation coefficients are known approximately for each kind of tissue. If you do not use some of the more elaborate brain phantoms available, I would recommend using one of them.


Marina Filipovic


To complement Marina’s answer, when using Gate, you know the composition of each tissue from the materials database.

You can use the nist database to compute attenuation coefficient at 511keV and build your attenuation coefficient image in cm-1.

Here is the link: https://physics.nist.gov/PhysRefData/Xcom/html/xcom1.html