Unsealed source radiotherapy

Unsealed Source Radiotherapy is a form of radiation therapy where the radioactive material is not contained in a sealed source but is instead administered to the patient in a liquid, gas, or capsule form. This method allows the radioactive substance to circulate throughout the body, targeting cancerous cells in various locations. Unsealed source radiotherapy is primarily used for systemic treatment, meaning it can treat cancers that have spread throughout the body or to treat certain non-cancerous conditions.

Overview

Unsealed source radiotherapy utilizes radioactive isotopes that emit radiation to destroy cancer cells or inhibit their growth. Unlike external beam radiation therapy, which directs radiation to a specific location from outside the body, unsealed source therapy works inside the body. The isotopes used in this therapy can be administered orally, injected into a vein, or instilled into a body cavity, depending on the type of cancer and the chosen isotope.

Types of Unsealed Source Radiotherapy

Several types of unsealed source radiotherapy are used in clinical practice, each utilizing different radioactive isotopes for various diseases:

• Radioiodine Therapy (Iodine-131): Commonly used for the treatment of thyroid cancer and some types of hyperthyroidism. The thyroid gland absorbs iodine, making Iodine-131 an effective treatment for targeting thyroid tissue.
• Radium-223 Dichloride: Used for treating bone metastases from prostate cancer. Radium-223 mimics calcium and targets bone, providing palliation of bone pain and reducing the risk of bone-related events.
• Strontium-89 and Samarium-153: These isotopes are also used for the relief of pain associated with bone metastases. They are absorbed by bone and deliver radiation directly to bone tumors.
• Yttrium-90 Microspheres: Used in selective internal radiation therapy (SIRT) for the treatment of liver tumors. Yttrium-90 microspheres are injected into the arteries that feed the tumor, delivering high doses of radiation directly to the tumor site.

Advantages and Disadvantages

The main advantage of unsealed source radiotherapy is its ability to treat the entire body or large areas of the body, making it suitable for conditions where cancer has spread to multiple locations. It is also beneficial in targeting small, diffuse tumors that are difficult to treat with surgery or external beam radiation.

However, there are disadvantages, including the risk of radiation exposure to healthy tissues and the potential for radiation-related side effects. Patients may also require isolation during the treatment period to prevent radiation exposure to others, depending on the type of isotope used.

Safety and Regulations

The use of unsealed radioactive sources in medicine is strictly regulated to ensure the safety of patients, healthcare workers, and the public. Regulations cover the procurement, handling, administration, and disposal of radioactive materials. Patients receiving unsealed source radiotherapy may need to follow specific safety guidelines to minimize radiation exposure to family members and the public.

Conclusion

Unsealed source radiotherapy is a valuable tool in the treatment of various cancers and some non-cancerous conditions. Its ability to target systemic disease makes it a critical component of cancer treatment, especially for conditions where traditional surgery or external radiation is not feasible. As with all medical treatments, the benefits of unsealed source radiotherapy must be weighed against the potential risks and side effects.