Why Have a PET/CT Bone Scan?
18F-Sodium Fluoride (NaF) bone PET/CT scans provide whole body views of the skeleton that are an important tool for the detection and evaluation of metastatic bone cancer. Assessment of bone metastases is important, since some of the most prevalent cancers are commonly associated with metastatic bone disease, including breast, prostate, and lung cancer.
Clinical areas in which 18F-Sodium Fluoride (NaF) PET/CT studies are valuable include: (1) Evaluation of metastatic bone disease; (2) Initial staging for patients at risk for bone metastases; (3) Situations in which exclusion of bone disease is required prior to initiation of potentially curative therapy; (4) Following patients with bone dominant metastases, to evaluate effectiveness of systemic therapy, and to exclude new metastases at critical anatomic sites.
Clinical Indications for 18F-Sodium Fluoride (NaF) PET/CT Studies
These studies are covered for Medicare beneficiaries with a known or suspected cancer through the National Oncologic PET Registry (NOPR). The NOPR guidelines allow for coverage for the following cancer indications:
Initial Treatment Strategy
- Diagnosis of suspected bone metastatic disease in patients who do not have a pathologically proven diagnosis of cancer
- Initial staging of a newly diagnosed cancer
Subsequent Treatment Strategies
Restaging/Detection of Suspected Recurrence
- Suspected new bone metastasis as a site of recurrence or progression
- Suspected progression of known ossesous metastasis
- Monitoring treatment response during systemic therapy
- Monitoring treatment response during radiation therapy
Monitoring treatment response during COMBINED systemic therapy and radiation therapy
Advantages of 18F-Sodium Fluoride (NaF) PET/CT studies over “conventional” bone scans using 99mTc-MDP
Until 2011, the primary tool for whole body imaging of the skeleton to assess metastatic disease was a bone scan utilizing the technesium-based radiopharmaceutical 99mTc-MDP. In recent years there has been increasing evidence in the medical literature regarding the utility and advantage of PET/CT studies utilizing the radiopharmaceutical 18F- Sodium Fluoride (NaF) for assessing bone cancer. In February of 2011, coverage was approved for Medicare beneficiaries for 18F- Sodium Fluoride (NaF) PET/CT bone studies for a number of clinical indications, as noted above.
18F-Sodium Fluoride (NaF) PET/CT bone studies have a number of advantages over conventional 99mTc-MDP studies:
- From a patient’s perspective, the 18F-Sodium Fluoride (NaF) PET/CT studies offer greater comfort and convenience, with far shorter scanning times than conventional 99mTc-MDP studies. While the waiting time between radiopharmaceutical injection and the actual scan is 45-60 minutes for 18F-Sodium Fluoride (NaF) PET/CT, the waiting time for a conventional bone scan is some 3 hours. The actual scanning time for the 18F-Sodium Fluoride (NaF) PET/CT is generally 15-20 minutes, as compared with 45-60 minutes for the conventional bone scan. While the complete 18F-Sodium Fluoride (NaF) PET/CT study will require about one hour, the 99mTc-MDP study will require some four hours.
- Higher accuracy in detecting both osteolytic and osteoblastic metastases
- Greater differentiation of benign versus malignant lesions
- Increased sensitivity over 99mTc scans
- Increased specificity over 99mTc scans
- Increased spatial and contrast resolution
- Fusion with anatomic information gained from integrated CT
- 3-axis and whole body viewing similar to FDG PET studies
- 18F Sodium Fluoride (NaF) radiopharmaceutical readily available for use. Supply of 18F Sodium Fluoride (NaF) is not constrained, as is the case with 99mTc
The advantages of 18F-Sodium Fluoride PET/CT bone studies over conventional 99mTc-MDP studies have been considered in the medical literature in recent years.
For instance, Frederick D. Grant et al published an article in the January 2008 Journal of Nuclear Medicine, “Skeletal PET with 18F-Flouride: Applying New Technology to an Old Tracer” that considers the advantages and clinical utility of 18F-Sodium Fluoride (NaF) PET/CT studies. For a pdf of this article, click here.
Other widely cited articles on the advantages of 18F-Sodium Fluoride PET/CT bone studies over conventional 99mTc-MDP studies include: