Treatment Response Evaluation of Bone Metastases Using ¹⁸F-NaF

¹⁸F-NaF PET/CT plays an essential role in initial staging, detection of suspected first skeletal metastasis, the suspected progression of bony metastases, or treatment monitoring in many types of cancer, such as prostate, breast, and lung cancer. The morphology and extent of osteoblastic bone metastases, especially when widespread throughout the skeleton, pose a challenge for conventional anatomic imaging to determine tumor load and to evaluate response to therapy. Conventional bone scintigraphy (BS) has been consistently proven to be an inaccurate and insensitive imaging tool to assess response to treatment in many metastatic cancers. ¹⁸F-Fluoride PET/CT can determine and assess the whole bone tumor burden quantitatively. Furthermore, ¹⁸F-Fluoride (a bone-seeking radiotracer for diagnosis) has uptake properties similar to a therapeutic radiotracer such as ²²³Ra (the bone-seeking radiotracer for therapy) has the potential to precisely assess the possibility and efficacy of a treatment. In this chapter, we review the use of ¹⁸F-NaF PET/CT in prostate, breast, lung, thyroid, and renal cell cancer and discuss ¹⁸F-NaF PET/CT’s capability to monitor therapy.