Why is it important to ensure clips marking the splenic pedicle appear consistently on portfilms?

Ensuring that the clips marking the splenic pedicle appear consistently on port films is crucial for verifying the central axis (CAX) location of the radiation beam. This consistency allows clinicians to confirm that the beam is targeting the intended area accurately while aligning with the treatment plan. Proper identification of the CAX is essential because it helps in assessing whether the prescribed dose is being delivered to the correct anatomical structures while protecting surrounding healthy tissues.

When the clips are visible and consistently positioned in the port films, it provides reassurance that the patient's setup and treatment delivery are correctly aligned with the planning computed tomography (CT) scans. If the clips were not consistently visible or accurately positioned, it might indicate a misalignment that could compromise the treatment's effectiveness or increase the risk of irradiating healthy tissues. Thus, having reliable visual markers is integral to ensuring that the treatment plan is implemented as intended and that the patient's safety is prioritized throughout the course of radiation therapy.