Patients are exposed to both the internal radiation from radiopharmaceutical and the external radiation from the X-rays during PET/CT examination. Estimating patients′ radiation dose from whole body PET/CT examination could eliminate their apprehension and give clinical physicians guidance about whether the patients need to perform PET/CT examination. The calculation methods, influencing factors, cancer risk of PET/CT imaging and how to reduce the radiation dose are reviewed in this paper.

Positron-emission tomography; Tomography, X-ray computed; Radiation dosage; Risk assessment