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.
