Historically, managing significant respiratory motion in thoracic/abdominal tumors required generous population-based CTV expansions, often irradiating excessive healthy lung and increasing toxicity risks.
The clinical integration of SGRT with 4DCT addresses this by enabling patient-specific, motion-adapted ITV definition and treatment delivery, thereby reducing normal tissue exposure while improving targeting accuracy.
This approach integrates 4DCT with the AccuTrak system using a retrospective method. During simulation, optical cameras track chest or abdominal motion, generating a respiratory waveform. 4DCT images are acquired synchronously, selectively capturing the tumor at specific phases of the breathing cycle. These images are used for planning, often employing reconstructions like Maximum Intensity Projection (MIP) and Average Intensity Projection (AvgIP), to design treatment for an optimal respiratory phase.
During treatment, the system automatically gates the radiation beam, turning it on only when the patient's breathing matches the planned phase, ensuring the tumor is within the treatment field. This respiratory-gated delivery minimizes the treated volume, reduces radiation exposure to healthy lung tissue, and enhances overall treatment efficiency

