Kv And Mv Cone-Beam Ct Imaging For Daily Localization: Commissioning, Qa, Clinical Use, And Limitations

Three‐dimensional conformal radiotherapy (3D‐CRT), intensity‐modulated radiotherapy (IMRT), and stereotactic body radiotherapy (SBRT) allow for the generation of highly conformal dose distributions for patients with tumor volumes wrapped around or adjacent to critical structures. As a consequence of steep dose gradients between the target and organs‐at‐risk, precise localization of the target volume and surrounding normal tissue is essential. However, variations in patient setup and organ motion are limiting factors in the accurate delivery of radiation treatment with a high degree of precision. Recent online image‐guided RT techniques using kilo‐Voltage cone‐beam CT (kV‐CBCT) and Mega‐Voltage CBCT (MV‐CBCT) are now offering the opportunity to overcome these limitations and greatly improve treatment localization accuracy. These IGRT techniques using the latest imaging technologies represent an improvement over traditional techniques such as 2D portal imaging. It allows for the use of volumetric online imaging to account for organ motion and setup variation by providing multiple anatomical views of the patient during the full course of RT treatment. The selection of imaging modality and system to use in support of a treatment protocol is often a compromise between image quality, efficiency, availability, and dose. The objective of this educational session is to review the current kV‐CBCT and MV‐CBCT imaging systems and their evolution for daily localization including 1. Commissioning, image quality, dose, registration process, and acquisition modes 2. Clinical integration 3. QA, stability over time, and downtime 4. Standard clinical applications 5. Novel clinical applications 6. Technology evolution and future directions