Image-Guided Radiation Therapy

Image-Guided Radiation Therapy (IGRT) uses imaging devices, such as X-rays, ultrasound and CT scans, to localize and guide the daily radiation treatment. On-board imaging improves the precision and effectiveness of treatments by allowing physicians to target and track tumors more accurately. The On-Board Imager provides IGRT by obtaining high-resolution X-ray images to pinpoint tumor sites, adjust patient positioning if necessary and complete a treatment, all within the time it would take to deliver standard treatment. IGRT is often used in conjunction with CT-on-Rails for prostate cancer patients. IGRT is also used to treat patients with certain lung and gynecologic cancers.

Fox Chase was among the first in the world to use IGRT and piloted its use helping it become a routine part of treatment.

Dynamic Multi-Leaf Collimator (DMLC) is a device that uses metal “leaves” to vary the intensity of radiation beams from the linear accelerator. By visualizing the shape and location of the tumor, radiation oncologists can determine the required beam angles for treatment. Beam intensity is regulated by calculating the size of the space between the leaves and how long they remain open. This delivers a lethal dose to the tumor, while protecting nearby critical organs.