Lymph nodes and bone are the most common sites of metastatic spread. Body scans are necessary to determine the extent of the cancer. CT scans and bone scans are used to detect lymph node and bone metastases respectively. Positron emission tomography (PET) scans provide additional information because they can detect metastases as small as 5-6 mm.
Standard bone scans use a radiotracer called Technetium-99, which is unfortunately not as accurate as PET technology. A PET scan called NaF-18 (radioactive sodium fluoride) provides superior specificity and sensitivity when compared with Technetium-99. NaF-18 PET imaging used in combination with Gallium-68 PSMA PET imaging offers the most comprehensive method currently available for detecting cancer metastases.