Radionuclide bone imaging

Types of tests: planar bone scintigraphy, SPECT/CT of the skeleton.

Aim: to visualize abnormalities of the skeleton (local areas of metabolic dysfunction of bone tissue).

Indications:

• to assess the outcomes of treatment of skeletal metastases
• to assess and stage primary bone tumors; to identify their recurrences
• to assess the spread of fibrous dysplasia of bone
• to make a differential diagnosis of metastases and other skeletal diseases
• to diagnose occult fractures and infected joint prostheses

Imaging agent: Tc-99m-labeled phosphate complexes. Tc-99m-labeled bisphosphonates The mechanism of visualization of metastases involves the inclusion of the imaging agent into the mineral metabolism of the bone tissue and its active storage in the areas of increased bone formation (mineralization), accompanying bone destruction process.

Principles: 2-3 hours after an intravenous injection of the imaging agent, a full body bone scan is made.

Preparation: No special preparation is necessary. After the injection, the patient is required to drink about 1 liter of water. The test is performed as soon as the patient has emptied their urinary bladder.

Nuances: bone scintigraphy is a high-sensitivity / low specificity test. In some instances, osteochondrosis, arthrosis and changes of the skeleton caused by trauma may lead to an erroneous conclusion. In this case, it is recommended to perform SPECT/CT. The use of Tc-99m-labeled bisphosphonates increases the sensitivity of the test.

SPECT/CT of the skeleton allows a better assessment of the condition of the skeleton if the results of bone scintigraphy are inconclusive. It helps to identify metastases that are 5-10 mm in size. It is a reliable technique for evaluating the efficacy of treatment of metastases with bisphosphonates and chemotherapeutic agents. SPECT/CT is recommended for patients with primary cancer of the prostate and breast, kidney and urinary bladder cancer, lung cancer (if PET/CT cannot be performed), melanoma, histiocytosis, malignant neoplasms of the gastrointestinal tract and reproductive system, embryonal tumor and osteosarcoma.