Bone-seeking radioisotope

A bone-seeking radioisotope is a specialized type of radioactive substance specifically designed to target bone cells and tumor cells that have metastasized, or spread, to the bone. By emitting low-level radiation, these radioisotopes can effectively kill cancer cells, making them valuable tools in the treatment and diagnosis of certain types of bone cancers.

Normal Bone Scan

Bone scan hand

Mechanism of Action

Once administered intravenously, the bone-seeking radioisotope travels through the bloodstream. Due to its affinity for bone cells, it selectively accumulates in the bones, especially in areas where bone turnover is high or where there are abnormalities, such as tumors. The accumulated radioisotope emits radiation, which damages the DNA of the targeted cells, eventually leading to cell death. Since cancer cells are generally more sensitive to radiation than normal cells, the treatment effectively kills tumor cells with minimal impact on surrounding healthy tissue.

Clinical Applications

Diagnosis

Bone-seeking radioisotopes can be used in conjunction with imaging studies, like the bone scan, to detect abnormalities in the bone. The emitted radiation can be captured and visualized, providing a detailed image of the distribution of the isotope in the bone, highlighting areas of concern.

Treatment

For patients with bone metastases, especially from cancers like prostate or breast cancer, treatment with bone-seeking radioisotopes can offer pain relief and reduce the progression of the disease.

Common Bone-Seeking Radioisotopes

• Strontium-89 (Strontium chloride Sr 89): Used both for pain relief in patients with bone metastases and as a therapeutic agent.
• Radium-223 (Radium Ra 223 dichloride): Specifically designed to treat prostate cancer that has spread to the bone and is resistant to medical or surgical treatments that lower testosterone.

Safety and Side Effects

While bone-seeking radioisotopes offer targeted treatment, they are not devoid of side effects. Common side effects include:

• Low blood counts
• Nausea
• Diarrhea
• Fatigue

Furthermore, because they involve the use of radiation, there are risks associated with radiation exposure, including potential damage to healthy cells. Therefore, it's crucial for patients to be monitored regularly and for the treatment to be administered under the guidance of trained specialists.

See Also

• Radiotherapy
• Bone cancer
• Metastasis
• Bone scan
• Radioactive decay

References

• Bone-seeking radioisotope entry in the public domain NCI Dictionary of Cancer Terms

Bone-seeking radioisotope Resources
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