Radiation Therapy Board Practice Exam

Image-guided radiation therapy (IGRT) relies on various imaging modalities to ensure accurate delivery of radiation to the target area while minimizing exposure to surrounding healthy tissues. The choice of the correct modalities is integral to achieving effective treatment.

CT (Computed Tomography) is extensively utilized in IGRT due to its ability to provide high-resolution images and detailed three-dimensional (3D) anatomical information. This capability is crucial for verifying the position of the tumor before and during treatment, allowing therapists to adjust patient positioning as necessary. CT imaging also aids in delineating the target volume, ensuring that radiation beams are precisely directed to the intended area.

Ultrasound is another valuable tool in IGRT. It is particularly useful because it is real-time imaging and does not involve ionizing radiation, making it a safe choice for patients. Ultrasound can help in monitoring soft tissue tumors, guiding treatments, and verifying patient positioning throughout the treatment course.

While other modalities like MRI (Magnetic Resonance Imaging) and PET (Positron Emission Tomography) provide important diagnostic information, they are not commonly used for the immediate purposes of IGRT during the active treatment phase. MRI does provide excellent soft tissue contrast but is less practical for daily positioning verification in radiation therapy due to