GE L6-12-RS: dark zone in the image under the probe lens
What happened
On a GE L6-12-RS linear probe, the image went dark (no picture) in a limited area directly under the acoustic lens, while the rest of the image stayed normal.
What was checked
- Press a finger on the lens over the darkened zone and watch the image while pressing.
- If the echogram appears under the finger, air is trapped under the lens; if the zone stays dark regardless of pressure, look for the cause elsewhere (probe elements, cable).
Cause
The engineers found that the acoustic lens had delaminated from the probe, leaving an air gap underneath. Air blocks the ultrasound beam, so the area under the delamination shows no image. This was confirmed in this single case by the finger-press test.
The cause is probable and was not fully confirmed.
What was done
Replacement of the probe's acoustic lens. In this one case the engineers considered lens replacement the recommended fix, with the outcome reported as probable — not a universal rule for every similar shadow.
Safety
Take the probe out of clinical use until the lens is replaced, and perform an electrical safety (leakage current) test before returning it to service — a delaminated lens can let fluids inside the probe.
Lesson: A fixed dark zone sitting exactly under one spot of the probe lens points to air under a delaminated acoustic lens, and a quick finger-press test separates this from a scanner or probe channel fault.
Covered in the course: Ultrasound Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.