The goal of this study is to create a phantom which can be used to test strategies for sealing the vaginal cavity, so that ultrasound gel can be used to fill the vaginal cavity improve the visibility of the vaginal cavity in MR-images.
Silicone rubber and PolyVinyl Alcohol (PVA) were tested, to check whether their mechanical properties can be used to mimic the bio-mechanical behaviour of Human Anterior Vaginal Wall (HAVW)-tissue. Both materials were used to produce a phantom. Contrast differences in MR-imaging of PVA-hydrogel and silicone rubber with ultrasound gel and air were measured, to verify proper contrast within a phantom. Both phantoms were used to test sealing strategies.
Young's moduli for HAVW-tissue were obtained from literature, and formed a range (6.7 - 14.4 MPa). Silicon proved a closer match to the HAVW-tissue, compared to PVA-hydrogel. Calculated Young's moduli were between 1.4 - 4.2 MPa (silicone rubber) and 0.04 - 0.16 MPa (PVA-hydrogel). Contrast differences in MR-images were measured between 177.8 and 1585.7, and proved sufficient enough to be spotted by an untrained eye. The sealing strategies using a probe cover surrounding a catheter, showed an increase of 54.3% (silicone rubber) and 119.9% (PVA-hydrogel) of the filling percentage measured. Indentation testing was confirmed as a possible alternative to tensile testing for the verification of mechanical properties. In this study the production process of a thin-walled double-layered phantom of the vaginal cavity has been developed and tested. The developed phantoms have been used to test strategies for sealing the vaginal cavity. The concept using a catheter surrounded by a probe cover, is considered to improve the sealing of the vaginal cavity.