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A project log for Open source ultrasound phantoms

Ultrasound Phantoms: War were declared

staticdet5staticdet5 05/03/2016 at 14:040 Comments

One of the identified issues with current DIY phantoms is that they're essentially made of growth medium (gelatin in water/agar). A well kept standard DIY phantom may last 10 days before it is overcome by mold. This can be enhanced a little bit by wiping it down with bleach (other cleaners appeared to break down the phantom), but it is ultimately a losing battle.

Breakdown is a pretty big issue as the surface of the phantom is critically important. Small, almost invisible imperfections, can cause apparently massive surface artifacts in an ultrasound. Two types of imperfections are really intrusive, but they're ultimately due to the same issue: Boundary Transition. Every time sound crosses a transition between objects with differing levels of sound transparency (speed of sound through the medium), some of the sound is reflected. The ultrasound imager relies on these reflections to visualize (it's literally the principle behind ultrasound imaging), but starts to have difficulty visualizing objects beyond the transition (less transmitted signal to utilize).

For this reason, surface imperfections are to be avoided as much as possible.

So, to start, I'm going to look at biocidial, but relatively innocuous substances to make the phantoms. On the list are bleach and vinegar, added to the water.

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