Image-Guided Radiation Therapy Procedure
Overview
Image-guided radiation therapy (IGRT) is a modern approach within radiation therapy that uses detailed imaging to help guide and improve the accuracy of treatment. Before each session, clinicians take high-quality images such as CT, MRI, or PET scans. These images ensure the radiation beams focus directly on the tumor, adjusting for any changes in the body’s position or shape.
Key Features:
- Use of advanced imaging for treatment planning.
- Increased accuracy in targeting cancer cells.
- Potential to use higher doses of radiation safely.
- Reduced impact on healthy tissues near the tumor.
IGRT has become the standard technique for many types of radiation treatments. Clinicians use it for many types of cancer, and sometimes for non-cancerous tumors. By closely tracking the tumor’s location, IGRT helps doctors deliver treatment safely and efficiently.
Because tumors can shift slightly between or even during treatments—due to breathing, digestion, or bladder filling—IGRT provides essential updates to ensure the radiation remains on target throughout the treatment course.
Reasons for Use
Image-guided radiation therapy (IGRT) allows clinicians to target tumors with high accuracy. This technique helps manage treatment for many cancers, such as lung, breast, prostate, and brain cancer.
The treatment team, which may include radiation therapists and a dosimetrist, uses detailed imaging to adjust the treatment plan if tumors move. IGRT also supports procedures like stereotactic radiosurgery for harder-to-reach tumors and protects healthy tissue nearby.
It is especially useful in treating tumors located near vital organs, where precision is critical—for example, near the spine, optic nerves, or gastrointestinal tract. IGRT can also play a role in re-irradiation, where a patient who has previously received radiation may need additional treatment. In these cases, real-time imaging helps minimize exposure to previously treated tissue.
Possible Dangers
Image-guided radiation therapy (IGRT) uses powerful doses of radiation to treat cancer, but it brings certain risks. The side effects usually depend on the area being treated and the strength of the radiation. Common reactions can show up during treatment, while some may not appear until long after.
| Area Treated | Usual Side Effects |
|---|---|
| Any body area | Hair loss at treatment spot, skin redness, severe fatigue |
| Head and neck | Dry mouth, thick saliva, trouble swallowing, mouth sores |
| Chest | Swallowing problems, cough, trouble breathing |
| Abdomen | Nausea, vomiting, diarrhea |
| Pelvis | Frequent urination, bladder issues, diarrhea, sexual change |
Sensitive parts of the body can react more strongly, especially with higher doses of radiation. Most short-term side effects can be managed and might fade after treatment stops. Late side effects can develop months or years after therapy ends. In very rare cases, radiation may cause a second cancer long after the first treatment.
Patients should discuss all possible risks with their healthcare provider. Emotional effects such as anxiety or fatigue may also accompany long-term treatments, and providers often suggest support groups or counseling. Skin changes, such as dryness or peeling, may continue even after treatment ends and might require special skin care routines.
How You Get Ready
Before starting image-guided radiation therapy (IGRT), a radiation oncologist usually meets with the patient to discuss treatment options and determine if IGRT is suitable. If they move forward, a team prepares a detailed plan and selects the needed imaging technologies. Common scans may include computed tomography (CT), cone-beam CT, or other advanced medical imaging.
These tools help pinpoint the tumor and the treatment area. When the patient arrives in the treatment room, staff may ask them to lie on a treatment table. The team checks positioning with additional imaging to ensure accuracy. Staff also perform quality assurance steps to make sure the setup is safe and precise.
Custom immobilization devices, such as molded cushions, masks, or vacuum bags, may be created to help the patient stay in the same position for each treatment. Patients may be asked to follow specific instructions before treatment, such as having a full or empty bladder, to help ensure reproducible positioning during each session.
What Patients Experience During Treatment
Before each session, clinicians may perform imaging scans like ultrasound or use images from equipment built into the linear accelerator. These scans confirm the exact location of the tumor. Medical teams check for any movement by comparing current images with previous ones.
Technologies such as fiducial markers (like gold markers), electromagnetic transponders, and portal imaging help with precise localization and patient positioning. This approach supports more accurate radiation delivery with improved image guidance.
Treatment sessions are typically short, often lasting 15 to 30 minutes, though exact times vary based on complexity and imaging needs. Patients are awake throughout the procedure and do not feel the radiation. Most describe the experience as lying still in a quiet room while the machine moves around them.
Outcomes
Doctors use imaging tests to check for changes after they use image-guided radiation therapy.
- Treatment Precision: This approach directs radiation exactly at the tumor.
- Adaptation Over Time: Results may appear quickly or take several weeks.
- Dose Distribution: More accurate targeting protects healthy tissues.
- Planning Target Volume (PTV): Regular imaging allows doctors to adjust treatment if the tumor shifts.
| Feature | Benefit |
|---|---|
| Enhanced precision | Targets tumor more accurately |
| Adaptive radiotherapy | Adjusts to tumor changes |
| Improved dose control | Keeps healthy tissue safer |
IGRT has contributed to better tumor control rates in many types of cancer by delivering higher doses safely while sparing normal tissue. It also allows for more individualized treatment strategies, as daily imaging data can guide small changes to treatment based on the patient’s anatomy that day. Many patients are able to complete their treatment course with fewer side effects and shorter recovery periods compared to older techniques.
