Internal Radiation - Cancer Science

What is Internal Radiation?

Internal radiation, also known as brachytherapy, is a type of radiation therapy used to treat cancer. Unlike external beam radiation therapy, which delivers radiation from outside the body, internal radiation involves placing radioactive materials directly inside or near the tumor. This method allows for a high dose of radiation to be delivered to a more localized area, reducing damage to surrounding healthy tissues.

How Does Internal Radiation Work?

Internal radiation works by inserting radioactive sources into the body. These sources can be in the form of seeds, ribbons, or wires. The radiation emitted from these sources damages the DNA of cancer cells, hindering their ability to reproduce and ultimately causing them to die. The precision of this treatment minimizes exposure to surrounding healthy tissue.

Types of Internal Radiation

There are several types of internal radiation, including:

1. Interstitial Brachytherapy: Radioactive sources are placed directly into the tumor tissue.
2. Intracavitary Brachytherapy: Radioactive sources are placed within a body cavity, such as the uterus or cervix.
3. Intraluminal Brachytherapy: Radioactive sources are placed within a lumen, such as the esophagus or bronchus.
4. Surface Brachytherapy: Radioactive sources are placed on the surface of the skin.

What Cancers Are Treated with Internal Radiation?

Internal radiation is used to treat various types of cancers, including:

- Prostate Cancer
- Cervical Cancer
- Breast Cancer
- Head and Neck Cancer
- Lung Cancer

Procedure for Internal Radiation

The procedure for internal radiation varies depending on the type of brachytherapy used. Generally, it involves the following steps:

1. Preparation: Imaging tests such as CT scans or MRIs may be used to determine the exact location of the tumor.
2. Placement: Under anesthesia, radioactive sources are placed into or near the tumor using applicators or needles.
3. Treatment Duration: The radioactive sources may be left in place for a few minutes to several days, depending on the prescribed dose.
4. Removal: If temporary sources are used, they are removed after the treatment duration. Permanent sources, such as seeds in prostate cancer, remain in the body but lose their radioactivity over time.

Benefits of Internal Radiation

Internal radiation offers several advantages:

- Precision: Delivers high doses of radiation directly to the tumor with minimal impact on surrounding healthy tissue.
- Efficiency: Treatments can often be completed in a shorter time frame compared to external beam radiation.
- Fewer Side Effects: Reduced exposure to healthy tissues often results in fewer side effects.

Risks and Side Effects

While internal radiation is generally safe, it can have side effects, including:

- Localized Pain or Discomfort: At the site of radioactive source placement.
- Bleeding: In rare cases, especially in intracavitary brachytherapy.
- Infection: Due to the invasive nature of the procedure.
- Fatigue: A common side effect of most cancer treatments.

Who is a Candidate for Internal Radiation?

Not all cancer patients are candidates for internal radiation. Factors that may influence eligibility include:

- Type and Stage of Cancer: Early-stage cancers are often more suitable.
- Location of Tumor: Tumors accessible for applicator placement.
- Overall Health: Patients must be healthy enough to undergo the procedure.

Conclusion

Internal radiation is a highly effective form of cancer treatment that targets tumors with precision, thereby reducing damage to healthy tissues. It is commonly used for cancers such as prostate, cervical, and breast cancer. While it offers numerous benefits, it is essential to consider potential risks and side effects. Consultation with an oncologist can help determine if internal radiation is an appropriate treatment option for a specific cancer type.