Medical Applications of Microwaves Suresh C. Mehrotra UGC-BSR Faculty Fellow Dr.Babasaheb Ambedkar Marathwada University, Aurangabad. Interdisciplinary research involving. Medical doctors Physics Chemistry Computer Science Electronic Engineers. Outline. What is microwaves?
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What is microwaves?
Why microwaves useful?
What microwaves used for?
use of microwaves,
applications in medical
.Research at Other Universities
Research at BAMU
They can Travel Through Various Types of Media
Microwaves received from far space gives information regarding types of molecules there
H, He, Water , formaldehyde etc and also their temperayures
Telecommunications: Mobile Phones
Why Use Microwaves?
Sometimes they can travel through the body
Sometimes they can heat the body
Example: Brain Temperature Monitoring
Before After adding Microwave
– Inverse scattering, non-linear relationship between the acquired data and imagined pattern, non-unique solution.
– Early solutions - linear approximation, more recent accurate solutions based on optimization.
– Are not all in agreement
– Limited sample sizes and frequency ranges
– Do not consistently distinguish between different normal tissue types
Source: Drs.Hagness & Okoniewski
– Susan C. Hagness, U. Wisconsin
– Elise C. Fear, U. Calgary
– Other groups
– Calibration: removal of the antenna artifacts
– Skin surface identification and artifact removal: reduce dominant reflection from skin - various algorithms
– Compensation: of frequency dependent propagation effects
– Tumor detection
– Optimal power coupling & surface cooling of the patient
– Shorter antennas (more elements): better control of focus and uniformity of B field in imaging
– No significant effect on S/N in imaging
A fast rising (20 ps) pulse is transmitted in the sample of interest.
The sample is placed in transmission line
The reflected pulse is recorded
Fourier Transform is used to extract the information.
Experiments have been perfoemed in vitro as well as in vivo
Statistically significant correlation was not observed between values of dielectric parameters and the different clinical stages of OSCC.
The mean values of permittivity and conductivity were higher in histopathological grade II as compared to grade I. Grade I had a higher relaxation time compared to grade II.
Thus, the values of dielectric parameters correlated well with the histopathological grades of OSCC and the difference was found to be extremely statistically significant (p<0.0001)
Interface To Laptop
Fig.1a:Instruments and Set up to acquire data from TDR
The feature vectors p are extracted for each set of measurements. These feature vectors are used as inputs to Linear Discriminate Analysis (LDA).
The measurements have been classified in three categories as follows:
Category 1. Subjects with no tobacco eating habits
Category 2: Subjects with tobacco eating habits
Category 3: Subjects with known cases of cancer (grade -1)
Category 4: Subjects with known cases of cancer (grade -2)
Category 5: Subjects with known cases of cancer (grade -3)
The LDA were used to classify above five known cases. The clustering obtained are shown below.
All feature vectors p’s are listed in Table 1. and Table 2 (Distance Matrix)