Which type of bone scan to order?

From the Guidelines

For most cases, a whole-body FDG-PET/CT scan is the preferred bone scan due to its superiority in detecting bone metastases compared to traditional Tc-99m bone scans. To perform this scan:

• Inject FDG (fluorodeoxyglucose) intravenously.
• Wait 1-2 hours for the radiotracer to distribute throughout the body.
• Perform imaging using a PET/CT scanner. This scan is effective for detecting various bone abnormalities, including:

• Metastatic bone disease
• Primary bone tumors
• Certain infections The FDG-PET/CT scan is preferred because:
• It provides a comprehensive view of the entire body, including the skeleton, in one examination.
• It's highly sensitive to metabolic changes in bone tissue, often detecting abnormalities before they're visible on other imaging modalities.
• Studies have shown its superiority over Tc-99m bone scans in detecting bone metastases, as seen in a study published in the Journal of the American College of Radiology 1. For specific conditions or body areas, alternatives may be considered:
• SPECT (Single Photon Emission Computed Tomography) for more detailed 3D images
• Focused scans of specific body regions for localized issues
• Traditional Tc-99m bone scans may still be used in certain situations where FDG-PET/CT is not available or contraindicated. The choice of bone scan should ultimately be based on the clinical indication, patient factors, and availability of imaging modalities, with consideration of the most recent evidence supporting the use of FDG-PET/CT scans 1.

From the FDA Drug Label

CLINICAL PHARMACOLOGY In vitro Tc 99m red blood cell labeling is accomplished by adding 1.0 to 3. 0 milliliters of autologous whole blood, anticoagulated with heparin or Anticoagulant Citrate Dextrose Solution (ACD), to the reaction vial. The FDA drug label does not answer the question.

From the Research

Types of Bone Scans

• Technetium-99m methylene diphosphonate (Tc-99m MDP) bone scan: This is the current standard of practice for the detection of osseous metastatic disease 2
• Positron emission tomography (PET): This has proven to be the gold standard in metabolic imaging and is superior to scintigraphy in the detection of metastases 2
• Combined technetium-99m hydroxy methylene diphosphonate and thallium-201 imaging: This is a sensitive and effective method for detecting bone metastases from thyroid carcinoma 3

Characteristics of Bone Scans

• Tc-99m MDP bone scan: This technique relies on the identification of the osteoblastic reaction of the involved bone rather than the detection of the tumor itself 2
• PET: This detects the presence of tumor directly by metabolic activity, rather than indirectly by showing tumor involvement due to increased bone mineral turnover 2
• Tc-99m MDP: This isotope is clearly localized along mineralization fronts and is occasionally found in the substance of the osteoid, but is absent from the cytoplasm and nuclei of osteoblasts and osteocytes 4

Applications of Bone Scans

• Detection of osseous metastatic disease: Tc-99m MDP bone scan is the current standard of practice 2
• Detection of bone metastases from thyroid carcinoma: Combined technetium-99m hydroxy methylene diphosphonate and thallium-201 imaging is a sensitive and effective method 3
• Evaluation of insufficiency fractures: Tc-99m MDP bone scan is a useful investigation for evaluation of insufficiency fractures 5