Image Guided Radiotherapy (IGRT) represents a sophisticated approach in cancer treatment, leveraging advanced imaging technologies to enhance the accuracy of radiation delivery. Imaging is integrated directly into the treatment process, allowing for precise targeting of cancerous cells. This method plays a significant role in modern oncology by improving the effectiveness of radiation therapy. IGRT ensures radiation beams are directed with high precision, a major advancement in tumor treatment.
How Image Guided Radiotherapy Works
IGRT uses imaging (CT, MRI, or ultrasound) to check the tumor’s exact location before and sometimes during treatment. These images are compared to the initial treatment plan, revealing changes in the tumor’s position, size, or shape. This ability to see real-time changes is particularly important for tumors that move, like those in the lungs or prostate.
Linear accelerators, which deliver radiation, are equipped with imaging equipment. This allows doctors to confirm the tumor’s precise location in the body before and during treatment sessions. Digital X-ray equipment on the treatment device can also image the patient’s internal anatomy just before or during treatment. These images are compared to the original planning CT series, enabling adjustments to the patient’s position or the radiation beam. If the tumor has shifted, the patient’s position or the radiation beam can be immediately corrected for accurate delivery.
The Precision Advantage
The precision offered by IGRT allows for higher radiation doses to be delivered directly to the tumor. This accuracy minimizes exposure to surrounding healthy tissues and organs. By focusing radiation on the target, IGRT reduces damage to healthy cells, leading to fewer side effects.
This targeted approach also improves treatment outcomes compared to traditional radiation therapy. Increasing the radiation dose to the tumor while sparing healthy tissue enhances treatment effectiveness. This precision is particularly beneficial for tumors located close to sensitive structures or organs, or for those that are prone to movement during treatment.
Common Applications
IGRT is used for tumors near sensitive structures and organs, or for those likely to move during or between treatment sessions. For instance, it is used in treating lung cancer, where tumors can shift due to breathing. Real-time imaging allows accurate targeting despite these movements.
Prostate cancer treatment also benefits from IGRT, as it enhances accuracy and reduces radiation exposure to nearby organs like the bladder and rectum. This minimizes side effects from damage to these sensitive areas. IGRT is also used for cancers of the head and neck, liver, and breast, where precise targeting is necessary due to critical structures’ proximity. It is also applied in brain and spine cancers, ensuring highly accurate radiation delivery to complex anatomical regions.
What to Expect During Treatment
The IGRT process begins with a simulation session. During this session, the patient is positioned and often fitted with immobilization devices to ensure they remain in the same position for each treatment. CT scans, and sometimes MRI or PET scans, create detailed reference images defining the tumor’s shape and location. These images form the basis for the personalized treatment plan.
On the day of treatment, the patient is positioned on the treatment table using the same setup and immobilization devices from the simulation. Before radiation delivery, imaging tests like X-rays or cone-beam CT scans are taken. These images are compared to initial planning images to verify the tumor’s current position and make necessary adjustments to the patient’s position or the radiation beam. Treatment sessions are usually short, often lasting only a few minutes, and are generally painless. While general radiation side effects can occur, IGRT’s targeted nature aims to reduce their severity by minimizing exposure to healthy tissues.