The overall goal of this procedure is to construct a multimodality quality assurance phantom for accurate tumor size measurement. First, make the test object tissue mimicking material and cast the test objects using silicone molds. Mount the test objects in a half cylindrical container and adhere thin non conducting aluminum.
Next, make the background tissue mimicking material and pour it into the container. Now seal the phantom tightly and rotate it in a rotator. This result is a multimodality phantom with potential to accurately simulate tumors Technical information on the construction of the multimodality qa.
Phantom is limited. Construction is challenging to learn because of the high accuracy required in the size of tumor stimulating test objects. This video demonstrates the important steps in construction of the phantom.
First, add 20 milliliters of commercial whole milk to a beaker. Then pass the milk through a 20 micrometer filter, and then through a 10 micrometer mesh filter. Next dissolve 0.02 grams of thi Marisol in 10 milliliters of the milk and stir it slowly.
Now using a house vacuum degas the milk solution for 30 seconds at room temperature. Next, dissolve 0.6 grams of dry aros in 10 milliliters of deionized water at room temperature, and stir slowly. Then add 0.79 milliliters of one propanol.
After desing the ARO solution, heat it in a 95 degrees Celsius water bath until the agro solution is clear. Meanwhile, heat the condensed milk in a 55 degree Celsius water bath. When the ARO solution looks clear, transfer the molten ARO solution to the 55 degree Celsius water bath.
Once equilibrated to 55 degrees Celsius, combine five milliliters of Agarro solution with five milliliters of condensed milk and slowly stir the mixture. Then add 1.7 milligrams of EDTA and one milligram of copper chloride to the agros milk mixture and stir a homogeneity on the silicone mold without one millimeter holes. Attach a nylon thread along the center of the spheres and glue it at both ends of the mold.
Using a soft brush, apply silicone grease on the surface of two molds and assemble two molds using alignment rods and rubber bands. Now, slowly inject the test object tissue mimicking material through the one millimeter holes of the silicone mold, using a 22 gauge needle of a syringe to avoid air bubbles. Then store the molds in a refrigerator for about 30 minutes until the test object set.
Next, unload the test objects from the mold and pass the nylon thread through the one millimeter holes in one side of the cylindrical container. Repeat this for the other side. Then mount the test objects in the container using scotch weld DP 100 and duct tape adhere thin non conducting aluminum onto the acrylic container.
Block the one millimeter holes in the acrylic container using the same glue to prepare the background tissue mimicking material. Filter commercial milk as before and then dissolve 0.2 grams of thy Marisol in 100 milliliters of the filtered milk and stir following this Degas the milk solution for 30 seconds at room temperature. Next, dissolve two grams of dry aros in 100 milliliters of deionized water at 7.9 milliliters of one propanol and one gram of barium sulfate.
Then slowly stir after degassing the ARO solution. Heat it in a 95 degree Celsius water bath until the ARO solution is clear. Meanwhile, heat the condensed milk in a 55 degree Celsius water bath.
Transfer the molten agro solution to the 55 degree Celsius water bath. Once equilibrated to 55 degrees Celsius, combine 50 milliliters of ARO solution with 50 milliliters of condensed milk. Slowly stir the mixture.
Then add 103 milligrams of EDTA and 60 milligrams of copper chloride to the aros mixture, followed by sufficient stirring. Add 0.1 grams of glass beads and stir. Then slowly pour the mixture through the six millimeter hole of the container.
After removing any air bubbles, glue the six millimeter hole using scotch weld DP 100. Once assembled, rotate the phantom at two RPM in the rotator for four to five hours. At room temperature, remove the nylon thread after the tissue mimicking materials in the phantom completely harden.
The phantom is now scanned in preclinical ultrasound, CT and MRI and images are acquired in three modalities. Shown here are test objects of varying diameter that were cast using silicone molds. There are no air bubbles in any test objects.
This preclinical multimodality phantom has five tumor simulating test objects. Its size is small enough to fit into any preclinical imaging modalities. Here are ultrasound, CT and MR images.
The contrast between test objects and background is sufficient to distinguish test objects and to measure their size in all three modalities. No severe artifacts are observed in any images except for small reverberation in the ultrasound images. After watching this video, you should have a good understanding of how to construct a multimodality qa, phantom For ultrasound CT and MRI, I believe there are several ways to construct a phantom with accuracy.
I have demonstrated one approach that can be adapted to build a phantom for other research purposes.
