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6. Workflow > 6.6. Therapy planning
6.6.6. Positioning the treatment volume
WARNING
Positioning:
Always leave sufficient safety margins to sensitive organs or other sensitive structures
when drawing Planning Target Volumes or cells.
Avoid placing treatment cells any closer to the spine or other sensitive structures than
indicated by the far-field safety margin. If this is not possible due to anatomic
constraints, monitor the sonication carefully and be prepared to stop it if needed.
Avoid placing treatment cells any closer to any tissue to be spared than indicated by the
cell safety margin. If this is not possible due to anatomic constraints, monitor the
sonication carefully and be prepared to stop it if needed.
Pay special attention to objects directly in the transducer beam area, not forgetting the
far field.
-
Air-filled structures and bones might cause unexpected reflections.
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Bowel should never be in the near field beam path. Heating the bowel may lead to
bowel perforation.
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Heating in the far field might lead to sciatic nerve damage / peritonitis.
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Some structures absorb the ultrasound waves completely, leading to more efficient
heating. Bone, bowel, clips, scars or any other rigid structure or air interface are
such structures.
Sonication through scar tissue, skin folds or navel should be avoided to prevent
damage. The beam shaping feature may be used to protect these. QuickCover
Ultrasound Protective Covers may be used to protect scars.
The planning graphics show the main part of the 3D focused transducer beam, but keep
in mind that boundaries such as air-filled structures and bones may cause unexpected
reflections.
WARNING
The displayed transducer beam does not take sonication power or duration into account. At
the highest sonication energies (large cells and high powers), you should leave at least a
few millimeters margin between the displayed transducer beam and any vital organs, with or
without beam shaping.
NOTICE
During actual therapy sonications, the 30 EM thermal dose contour should be used as another
measure of the probably affected area.
Sonication with electronic X deflection requires higher power levels and thus also larger safety
margins.
NOTICE
The orientation of the image on the screen is not always according to the radiological convention
used in the MR console. The image orientation can be seen in the anatomical orientation
indicators.
Instructions for Use
109745C2 / 02-2022
107 (192)
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