to see the temperature inside microwave thermal imaging

To See the Temperature InsideMicrowave Thermal Imaging

Qianqian Fang

Thayer School of EngineeringDartmouth CollegeAdvisor: Keith PaulsenAcknowledgement: Paul Meaney, Margaret Fanning, Dun Li, Navin Yagnamurthy

Computated Tomography (CT)

Single Photon/Positron Emission Computed

tomography(SPECT/PET)

MRI(T2 weighted)

Magnetic Resonance Imager (T1 weighted)

MRI(PD weighted)

Qianqian Fang, Mar, 2001

Microwave Imaging SystemResearch Background

Overview of temperature detection methodsPrincipals and algorithm of MISHardware configurations

Progress in MIS groupPhantom experimentsIn Vivo experiments

For thermal monitoring


Research BackgroundMedical Thermal Imaging Methods:

Invasive - Direct Measurement• Thermocouple Probes

Non-Invasive1. MR(Magnetic Resonance)2. Ultrasound3. Microwave


Comparisons of Imaging Methods

Methods Measure Type Clinical

Cost Accuracy

Thermocouple Probes Temperature(Directly)

Invasive Yes Low 0.3~0.5 oC

MR Density of Protons

Non-invasive

Yes High 1 oC

Ultrasound Sound Speed Non-invasive

No Low ??

Microwave PermittivityConductivity

Non-invasive

No Low 1 oC


How Microwave Imaging WorksLinear Relationship between temperature and permittivity and conductivity, especially conductivity, generally there is a 1-2% increase per oC

Antenna Responses

ε and σ

Temperature

Reconstruction

Linear Relationship


Forward Problem and Inverse ProblemForward Problem and Inverse Problem

known unknown

Scattering Problem

Inverse Scattering Problem

FEM

FD

MoM

BEM

….

The Procedure of Reconstruction is an Inverse Scattering Problem


Overview of Algorithm

Object

Algorithm of MISAlgorithm of CT

•Newton Method•FEM+BEM•Dualmesh scheme

Linear Reconstruction Non-Linear Reconstruction


Hardware ConfigurationsTheoretical Model Snapshot

Computer Control

Antenna Array

Water Heating Pipe

Microwave Feeding Cables

Transmit /Receive Module

Animal Ventilation

Pipes


Monopole Antenna Array

Dielectric Insulator

Monopole Antenna

Array Plate

Coaxial Feed Lines


CT Scanner in the Experiments

•Possible Property Initial Guess•Verification of Thermal Sensor location



Overview of temperature detection methodsPrincipals and algorithm of MISHardware Configurations

Progress in MIS groupPhantom ExperimentsIn Vivo Experiments



Sausage Experiment(Phantom)


Sausage Experiments Data Analysis

Conductivity

Position


Heated Saline TubeRelative Permittivity Conductivity (S/m) Difference (Conductivity)

Heated Tube of Saline 25 0C

34.8 0C

41.8 0C


Pig Experiments(In Vivo)


Pig Experiments - ResultsReconstruction Results Differences

42-36 45-36

543210-1-2-3-4-5

42d-36 39d-36 36d-36

543210-1-2-3-4-5

39-36

0.20.170.140.110.080.050.02-0.01-0.04-0.07-0.1

0.20.170.140.110.080.050.02-0.01-0.04-0.07-0.1

diff 900 MHz Pig 020101 - Reference 36 degrees900 MHz Pig 020101 - LS0 tik1 marq1

32.72.42.11.81.51.20.90.60.30

32.72.42.11.81.51.20.90.60.30

90817263544536271890

39 42 45

90817263544536271890

42d 39d 36d



Overview of temperature detection methodsPrincipals and algorithm of MISHardware Configurations

Progress in MIS groupPhantom ExperimentsIn Vivo Experiments



Thermal Imaging Wizard

InterfacePC

Calculation UNIX

SSH Telnet

SSH FTP

Other Features•File Name Template•Multi-user support•Configuration Profile Structure


Reconstruction Program Structure

Preprocessor

Phase UnwrapOld Method

Post-processor

to see the temperature inside microwave thermal imaging

Documents