Internal Radiation (Brachytherapy)

Internal Radiation

Internal radiation, also known as brachytherapy, is a specialized cancer treatment where radioactive material is placed directly inside or very close to a tumor. This allows doctors to deliver a much higher, more concentrated dose of radiation to the cancer cells while significantly reducing the exposure to nearby healthy organs. Real-time Image-Guided Brachytherapy (IGBT) using MRI has become a primary standard for achieving this level of precision.

When You Should Consider Brachytherapy

• Cervical or Uterine Cancer: Often used after external radiation to provide a "boost" dose directly to the cervix or vaginal cuff.

• Prostate Cancer: For localized disease, either as a standalone treatment using permanent seeds or as a high-dose temporary boost.

• Breast Cancer: Following a lumpectomy, to provide Accelerated Partial Breast Irradiation (APBI) in a shorter timeframe than traditional radiation.

• Skin Cancer: For certain non-melanoma skin cancers on the face or nose where surgery might cause significant scarring.

• Head and Neck Cancer: For tumors of the tongue, lip, or floor of the mouth that require a localized, intense dose.

Types of Brachytherapy

• HDR (High-Dose Rate): A high-strength radioactive source is pulsed into the body through a catheter for about 10 to 20 minutes and then completely removed.

• LDR (Low-Dose Rate): Radioactive "seeds" are permanently or temporarily implanted, releasing radiation slowly over several days or months.

• PDR (Pulsed-Dose Rate): A hybrid approach where radiation is delivered in short pulses every hour, typically over one or more days in a hospital setting.

• Permanent Seed Implants: Common in prostate cancer; tiny seeds (the size of a grain of rice) are left in the body and become inactive over time.

• Temporary Brachytherapy: The radioactive source (such as ribbons or wires) is removed from the body once the treatment session or hospital stay is complete.

How Is Performed

• Anesthesia: Depending on the site, the procedure is performed under local, spinal, or general anesthesia (common for gynecologic or prostate cases).

• Applicator Placement: Doctors use catheters, needles, or specialized applicators (such as tandem and ovoid) to create a pathway to the tumor.

• Image Guidance: Real-time ultrasound, CT, or MRI is used to ensure the applicators are positioned with sub-millimeter accuracy.

• Afterloading: A computerized machine (the afterloader) sends the radioactive source into the applicators for the precise duration calculated by the physics team.

• Source Retraction: Once the treatment is finished, the source is safely retracted back into the shielded machine, leaving no radiation in the patient (for HDR).

Pre-Procedure Preparation

• Imaging Workup: A high-resolution MRI or CT scan to measure the exact volume of the tumor and its proximity to organs like the bladder or rectum.

• Bowel Preparation: Following a liquid diet or using an enema if the treatment area is near the pelvis to ensure clear imaging.

• Fasting (NPO): Adhering to strict fasting protocols if the procedure requires general or spinal anesthesia.

• Medication Review: Stopping blood thinners or anti-inflammatory drugs several days before the needle or catheter insertion.

• Baseline Symptom Check: Documenting current urinary or bowel habits to monitor for any changes following the procedure.

Tests Before Brachytherapy

• Pelvic or Transrectal Ultrasound: To map the anatomy and determine the number of needles or seeds required for the specific site.

• Cardiac/Respiratory Clearance: A chest X-ray and EKG to ensure the heart and lungs are healthy enough for anesthesia.

• Coagulation Profile (PT/INR): To ensure the blood clots normally before any needles are inserted into the tissue.

• Urinalysis: To rule out any active urinary tract infections before performing prostate or gynecologic brachytherapy.

• Kidney Function (Creatinine): Assessed especially if contrast dye will be used during the planning CT scan.

Life After Brachytherapy (Recovery & Safety)

• Radiation Safety: For HDR, you are not radioactive and can be around others immediately. For permanent seeds, you may need to avoid close contact with children or pregnant women for a few weeks.

• Localized Soreness: Expect mild swelling, bruising, or tenderness at the insertion site for 2 to 5 days.

• Urinary/Bowel Changes: Temporary urgency or frequency may occur if the treatment area was located near the bladder or rectum.

• Tissue Health: For gynecologic cases, using a vaginal dilator or prescribed creams may be recommended to prevent narrowing (stenosis) and maintain health.

• Activity Resumption: Most patients return to their normal daily routines within a few days once the initial soreness fades.

Why Specialized Treatment Is Highly Effective

• Maximized Dose: Delivers a "lethal" dose to the tumor that is significantly higher than what can be safely achieved with external beams alone.

• Extreme Precision: Because the source is inside the tumor, the radiation dose drops off rapidly, sparing healthy tissues just millimeters away.

• Shorter Treatment Times: Some HDR protocols allow a full course of radiation to be completed in just 1 to 5 days instead of several weeks.

• Organ Preservation: Provides an alternative to major surgery for certain cancers, preserving the function of the breast, prostate, or tongue.

• Adaptive Planning: Modern 3D/4D planning allows doctors to adjust the dose in real-time based on the exact shape of the tumor on the day of treatment.