Ct is a computerized X-ray tomography technique and an examination method, which can basically see the anatomical structure clearly.
Spect is a single photon emission computed tomography, which images the tracer emitted by patients with gamma rays.
Mri is magnetic resonance imaging, which is superior to ct in the aspects of nervous system, liver and joints.
Pet is an advanced clinical imaging technology of positron emission computed tomography in the field of nuclear medicine.
Pet-ct is a positron emission computed tomography, which is a combination of PET and ct. It has more information than pet plus ct. It is a very advanced technology in the field of nuclear medicine at present, and is mostly used for early diagnosis and clinical diagnosis of tumors.
Ct and MRI belong to radiology, spect and pet belong to nuclear medicine.