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
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
Qianqian Fang, Mar, 2001
Research BackgroundMedical Thermal Imaging Methods:
Invasive - Direct Measurement• Thermocouple Probes
Non-Invasive1. MR(Magnetic Resonance)2. Ultrasound3. Microwave
Qianqian Fang, Mar, 2001
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
Qianqian Fang, Mar, 2001
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
Qianqian Fang, Mar, 2001
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
Qianqian Fang, Mar, 2001
Overview of Algorithm
Object
Algorithm of MISAlgorithm of CT
•Newton Method•FEM+BEM•Dualmesh scheme
Linear Reconstruction Non-Linear Reconstruction
Qianqian Fang, Mar, 2001
Hardware ConfigurationsTheoretical Model Snapshot
Computer Control
Antenna Array
Water Heating Pipe
Microwave Feeding Cables
Transmit /Receive Module
Animal Ventilation
Pipes
Qianqian Fang, Mar, 2001
Monopole Antenna Array
Dielectric Insulator
Monopole Antenna
Array Plate
Coaxial Feed Lines
Qianqian Fang, Mar, 2001
CT Scanner in the Experiments
•Possible Property Initial Guess•Verification of Thermal Sensor location
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
Qianqian Fang, Mar, 2001
Sausage Experiment(Phantom)
Qianqian Fang, Mar, 2001
Sausage Experiments Data Analysis
Conductivity
Position
Qianqian Fang, Mar, 2001
Heated Saline TubeRelative Permittivity Conductivity (S/m) Difference (Conductivity)
Heated Tube of Saline 25 0C
34.8 0C
41.8 0C
Qianqian Fang, Mar, 2001
Pig Experiments(In Vivo)
Qianqian Fang, Mar, 2001
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
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
Qianqian Fang, Mar, 2001
Thermal Imaging Wizard
InterfacePC
Calculation UNIX
SSH Telnet
SSH FTP
Other Features•File Name Template•Multi-user support•Configuration Profile Structure
Qianqian Fang, Mar, 2001
Reconstruction Program Structure
Preprocessor
Phase UnwrapOld Method
Post-processor