Where can I find some free mri, ct, or pet scans facilities?

Teaching Hospital. There are several considerations. Are you poor/indigent ? You may qualify for a markedly reduced or free scan if you have a problem that necessitates one of the above scans at a teaching or university hospital. Maybe a free scan if you qualify for a research protocol .
Free Clinic. If there is a free clinic in your area they may have an agreement with local radiology facilities to offer mri/ct scans if the physician at the free clinic believes that it is necessary.