This study investigates the use of a markerless tracking method for patients receiving radiation therapy for conditions such as brain, breast, head and neck, kidney, liver, pancreas, prostate, spine cancers, and cardiac arrhythmia. It focuses on real-time image guidance during treatment.

The study evaluates the effectiveness and accuracy of the markerless tracking method by analyzing routinely acquired patient data. This method enhances the precision of radiation therapy by tracking tumor and organ movement without the need for physical markers.

• Who can participate: Adults 18 years and older who are receiving radiation therapy for specific cancers or cardiac arrhythmia at a participating center and can provide written consent are eligible.
• Study details: Participants will undergo radiation therapy with standard imaging procedures. The study involves comparing the markerless tracking results with a 'ground truth' to assess accuracy. A placebo is not involved.