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6. Workflow > 6.8. Therapy
6.8.2. Planning the sonication order
The Sonalleve MR-HIFU system allows you to sonicate the treatment cells in any order. However,
the following general guidelines apply to the sonication order:
To avoid unnecessary heating in the near field (skin or the inner margin of the subcutaneous fat
layer, abdomen), start the sonications from the cells on the treatment plane deepest within the
body.
Treat all the cells on a treatment plane before moving on to the next plane.
Clusters can be used as an aid in planning the sonication order.
To minimize the risk of heating the skin or the inner margin of the subcutaneous fat layer, avoid
successive sonications in the same cluster. Instead, move between clusters/target volumes in
different parts of the Total Treatment Volume. This allows for better cooling and more even
heating in the volume.
6.8.3. Determining the correct frequency level for a treatment cell
Ultrasound attenuation is a function of ultrasound frequency in biological tissues.
Use the lower frequencies when near field heating is to be avoided.
Use the higher frequencies when near field heating is not an issue but far field heating is to be
avoided.
6.8.4. Determining the correct power level for a treatment cell
To ensure that the treatment volume heats sufficiently, but not excessively, you must determine a
suitable initial power level for each treatment cell size. When you have sonicated the first few cells
with this power level, you should evaluate the results and adjust the power level based on them.
WARNING
Start therapy with low energies and observe carefully temperature changes during the first
sonications. Failure to do so may cause heat spreading outside of the intended region
causing unintended tissue damage and pain.
WARNING
Use the high powers above 250 W only if lower powers do not produce temperature
elevation high enough for ablation. Consider the risk of unintended damage to nearby
sensitive organs and structures when using the high powers. Carefully monitor the heating
in the near field, far field and near sensitive organs and be prepared to stop the sonication
immediately if needed.
Instructions for Use
109745C2 / 02-2022
119 (192)
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