[1] SPECT imaging is conducting by injecting a radioactive probe (or tracer) into the person's blood stream.
This type of imaging can sometimes allow the team to gain more information about the function of certain body tissues to help diagnose certain medical conditions.
[1] PET imaging has applications for treating and diagnosing cancer.
These isotopes are absorbed by different tissues in the body, including malignant tumour cells, and PET imaging can visualize the function or detect tumour cells by visualizing how the isotopes are processed by different cell types and how they decay.
[2] The imaging agent used in SPECT emits gamma rays, as opposed to the positron emitters (such as 18F) used in PET.