Indiana University-Purdue University Indianapolis (IUPUI) / This research focuses on the detection of arterial blockage due to LDL (low density
lipoprotein). Arterial blockages are related to two kinds of fats LDL and the HDL.
HDL being the good fat, the patient does not have to undergo the biopsy, while in
case of LDL, biopsy should be performed. Issues associated with invasive approaches
raise safety concerns for patients such as infection, longer operation durations, longer
recovery time etc. This research focuses on a noninvasive imaging technique to detect
the kind of block age. Photo acoustic approach was investigated in order to simulate
human tissues leading to medical diagnosis and treatment. Photo acoustic imaging
involves production of an image on absorption of laser pulses. The laser pulses are
further scattered and absorbed producing heat. The goals of the study were to categorize
the type of the tissue materials based on the output temperature distribution
via IR sensors and reflected acoustic waves via acoustic pressure sensors. The reflected acoustic wave and IR thermal distribution may be applied towards arterial
blockages to differentiate the different types of tissue layers. The simulation results
should have implications towards the future implementation of the practical devices
and system. Parameters including energy levels, tissue thicknesses, frequencies, penetration
depth, and the densities of the LDL/HDL fat materials were considered.
Various energy pulses; 1j, 3j, and 5j were considered as input sources to the tissue
materials (single or multi layers). The simulated layers considered in the study were
the skin, bone, blood, and fat cells.
The temperature and acoustic pressure response over the various layers were analyzed
for the detection of blockages. The ndings of the temperature and acoustic
pressure ranges can be detected by MEMS/NEMS (Micro electro mechanical systems/
nano electro mechanical systems) sensors, such as IR and Piezoelectric devices.
Bioheat and acoustic wave equations were solved simultaneously using COMSOL
software for multiple layers. The proper boundary conditions were provided in
the solutions of these equations. The scattering and transmission acoustic wave, and
the temperature distributions, may be used as guide to the integrated sensor system
design for future consideration. The simulation was performed in four stages:
(1) Single layer and multiple layers at a given frequency and energy level
(2) Multiple layers at a given frequency for different energy levels
(3) Multiple layers at a given energy level for different frequency and
(4) Multiple layers at a given frequency and energy levels with different size tissues.
The simulation results showed that a range of acoustic pressure between 240 and
260 need to be detected, with a di erential temperature distribution in kelvin range.
Power pulses of 10MPa showed a temperature change of 175, which is believed to be
within the
exible substrate sensing devices that may be used for the practical model
of this research.
The thesis covers a proposed system for the practical model following the simulation
results received in this study.
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/15106 |
| Date | 12 1900 |
| Creators | Kakani, Monika |
| Contributors | Rizkalla, Maher |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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