What is the recommended focus to film distance in standard simulation settings?

In standard simulation settings for radiation therapy, the recommended focus to film distance is typically 140 cm. This distance is chosen to provide a balance between minimizing geometric distortion and achieving a sufficient field size for accurate treatment planning. At this distance, the beam can be properly collimated and focused, which ensures that the entire treatment area is adequately covered while maintaining optimal image quality for contouring and dose distribution evaluation.

This distance allows for a good approximation of the clinical setup, as it mirrors the treatment distances used in actual therapy procedures. Proper calibration and accuracy are crucial in dosimetry, and using the standard focus to film distance of 140 cm helps in achieving reliable results during the simulation process. This aids in effective treatment planning and patient outcomes, enhancing the precision of the radiation delivered to the target area.