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Molecular imaging of cancer

4 important questions on Molecular imaging of cancer

What are the 6 reasons to use molecular imaging for diagnosis, therapy or both?

Diagnosis:

measure of the stage of disease
prognosis to predict disease behavior
identify a target for therapy

Therapy:

measure the response to therapy
elucidate cancer biology

Both therapy & diagnosis:

predict response to therapy

Explain the principle of radionuclide imaging

Radionuclide imaging relies on the tracer principle in which an amount of radioactive tracer is injected into the body to monitor a physiological or biochemical process.
Radiotracers are radionuclides coupled to a carrier molecule. The radionuclide is required for imaging, its half-like should therefore match the pharmacokinetics of the carrier molecule. The carrier molecule itself is designed to target a specific process or receptor. This radiotracer can either be detected using SPECT (single photon emission computed tomography) or by PET (positron emission tomography)

What are the advantages and disadvantages of PET and SPECT?

PET advantages: higher resolution, higher sensitivity (no collimator), more accurate quantification
PET disadvantages: higher costs of tracer development, more advanced radiolabeling

SPECT advantages: lower cost of tracer development, more widely available, lower half-lives of isotopes
SPECT disadvantages: lower resolution (only clinical), lower sensitivity (collimator), quantification more challenging