diafragmapositionering

Diafragmapositionering is the deliberate control and documentation of the position of the diaphragm during imaging or treatment to improve accuracy, reproducibility, and image quality. The diaphragm is a major source of motion in the upper abdomen and lower thorax, and its position varies with breathing, posture, and patient effort. Positioning efforts may be employed to achieve a consistent diaphragmatic level between sessions or to align target structures with imaging or therapeutic beams.

In diagnostic imaging, consistent diaphragmatic position helps reduce motion blur and improves the visualization of structures and lesions near the diaphragm, such as in chest and upper abdominal radiographs, CT, or MRI. In radiotherapy and image-guided procedures, diaphragmatic positioning supports more reliable contouring and dose delivery by limiting organ motion, thereby potentially reducing margins and sparing adjacent healthy tissue.

Techniques used to achieve diaphragmatic positioning include adjustments to patient posture, respiratory coaching, and breath-hold strategies. Common methods involve controlled breathing patterns (deep inspiration or shallow breathing), breath-hold devices, abdominal compression, and the use of external markers or imaging surrogates to verify diaphragm level. Respiratory gating and motion-management approaches may be combined to maintain the desired diaphragm position during treatment.

Limitations include variability in patient tolerance and effort, differences in breath-hold quality, and contraindications for some individuals. Diaphragmatic positioning is typically one aspect of broader motion management practices in diagnostic radiology and radiation therapy.