Question
I have acrylic inserts filled with liquid contrast for my QUASAR MRI 4D Motion Phantom or my QUASAR Multi-Purpose Body Phantom.
The inserts cannot fit into the phantom, even though they previously were fitting. How do I address this?
Answer
We find it is rare cases where swelling occurs, as our manufacturing process includes pre-treatment and conditioning of the plastics to prevent deformation or swelling. But, despite our best efforts, we do sometimes observe that the inserts filled with water-based solutions are sometimes affected because of such tight-fitting tolerances and prolonged storage.
Here are a few steps we can follow to resolve the issue:
1. Drying Out the Components: Empty the liquid from the body phantom and hollow ovals, and let them "dry out" for 5-10 days. You could store the contrast liquid separately to refill the components after the drying period. This will help determine if the parts shrink enough to fit properly when dry. If they fit, refill them with the contrast solution to see if the interference reoccurs.
2. Testing Fit and Sanding: Test the fit of each insert in each body cavity from different directions. If the interference is localized, you might use fine grit sandpaper (e.g., 220) to reduce the interference. This process involves testing the fit between sanding attempts. Although the sandpaper will scratch the surface, you can smooth out the scratches with very fine grit sandpaper (emery cloth) after confirming the fit. Note that this method is only useful for isolated. small, detectable spots. It's too time-intensive and cumbersome for me to recommend sanding the insert in its entirety.
3. Sending for Evaluation: If the drying and sanding methods do not resolve the issue, you can send the empty oval and inserts back to Modus. Our machine shop can evaluate whether they can fix the interference issue. If repair is possible, we will provide a quote before proceeding. If repair is not feasible, purchasing replacement parts may be the only option.