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YousefiDarestani, MohammadReza

University of British Columbia

The range of applications in which ureteral stents can be used are extremely wide but its role in most cases is to bridge the flow of urine from the kidney to the bladder. While ureteral stenting is an unmistakably effective procedure to address ureteral obstruction, it can lead to long-term adverse effects. These effects include narrowing of the ureter caused by encrustation of the stent, resulting in hydronephrosis, kidney swelling, and potential decrease of kidney function, possibly leading to kidney failure. The issue can go unnoticed and become aggravated particularly when patients are without symptoms. Currently, assessing kidney swelling typically requires costly radiological procedures, some of which expose patients to ionizing radiation. This thesis aims to explore and develop a novel intelligent ureteral stent featuring a radiofrequency antenna and a micro pressure sensor for real-time wireless kidney pressure monitoring via resonance frequency, potentially enabling early detection of hydronephrosis. The tubular construction of a commercial ureteral stent serves as the basis for integrating an antenna and a micro capacitive pressure sensor, which are electrically coupled to form resonant circuitry. The resonance frequency of the inductor-capacitor (LC) tank on the ureteral stent is determined by the local in-vivo pressure around the device. The wireless detection of the LC tank's resonance frequency is accomplished using an external antenna that is placed on the patient’s skin close to the indwelling stent to track pressure changes in the kidney. This technique aims to enable early detection of hydronephrosis, thereby preventing kidney injury. The stent device is encapsulated using Parylene C to ensure both biocompatibility and electrical insulation within a real-world environment, which includes exposure to urine, an electrically conductive liquid. Various designs of intelligent ureteral stent prototypes are evaluated in different scenarios, including in-vitro and ex-vivo tests utilizing harvested pig kidney-ureter tissue. Ex-vivo results confirm the device's design effectiveness and its compatibility with standard stenting procedure. Further enhancements are suggested to ensure the device's capability in detecting hydronephrosis, indicating its potential for real-life clinical trials. Moreover, by making further adjustments and customizations, this technology can be applied in various biomedical devices requiring novel sensing technology.

Text

2024-09-04

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/89163

Biomedical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/