Table 2 Unit design and testing
From: Building low-cost simulators for invasive ultrasound-guided procedures using the V-model
Material Description of materials that were tested for each unit | Unit test How the unit corresponds to the user requirements | Integration test How the unit integrates with the other units |
|---|---|---|
Fetus | ||
#1 Silicone | Low resemblance Appropriate size | Visible on ultrasound |
Amniotic cavity: | ||
#1 Round latex balloon 16″ with 280 ml water | Visible on ultrasound, too small | – |
#2 Round latex balloon 18″ with 280 ml water | Visible on ultrasound, appropriate size | Could be fixated easily in the base. Integrated well with the fetus and the placenta #5 |
#3 Round latex balloon 24″ with 280 ml water | Visible on ultrasound, too big | – |
Placenta | ||
#1 Ballistic gel with red pigmentation | High resemblance, could get a sample however low resemblance to placenta Reusable | Not clearly discriminated from top layer on ultrasound |
#2 Ballistic gel with graphite | Medium resemblance on ultrasound, could get a sample however low resemblance to placenta Reusable | Not clearly discriminated from top layer on ultrasound |
#3 Starch with/without honeycomb in a condom | Low resemblance on ultrasound, could not provide a sample | – |
#4 Starch in a silicone-mold | Silicone mold interrupted soundwaves, could not provide a sample | – |
#5 Tofu | Medium resemblance on ultrasound Could get a sample however low resemblance to placenta | Clearly discriminated from top layer. Difficult to assemble with the amniotic cavity. Moderate cost |
#5 Balloon with ultrasound gel | High resemblance On ultrasound Could not provide a sample | Clearly discriminated from top layer. Easily assembled with the amniotic cavity. Low cost |
Top layer | ||
#1 Ballistic gel with coal + thin skin-colored silicone-layer on top | Medium/high resemblance Silicone layer would have to be remade after a certain number of uses | The silicone reduced the clarity of underlying structures on ultrasound and was difficult to fixate on the model |
#2 Ballistic gel with coal | Low/medium resemblance, afford resistance during puncture, reusable | Afforded discrimination between anatomic structures below |