seminar ppt
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Non-Invasive Blood Glucose Measuring System
PRESENTED BY:
MD. NAJMI ALAM
1MJ07TE027
TELECOMMUNICATION
MVJ COLLEGE OF ENGINEERING
Under the guidance of:Mrs. Navya Vipin
Asst Prof., Dept. of TEMVJCE
Head of the DepartmentMrs. Savitha H.K
Asst Prof., Dept. of TE MVJCE
Diabetes Mellitus
A metabolic disorder in which our body is unable toregulate the level of glucose in the blood
Most prevalent non-communicable disease
More than 150 million diabetic patients in the world
Management of diabetes
Diabetes related long term complications are leadingcause of death
The complications can be reduced by 50-75% by tighterglycemic control
Frequent monitoring Adjusting the medical nutritional therapy, exerciseand medications to prevent hyper- or hypoglycemia
(Source : The Diabetes Control and Complications Trial Research Group, ‘The effect of intensive treatment ofdiabetes on the development and progression of long terms complications in insulin-dependent diabetes mellitus’,
N. Engl. J. Med. 329(14), 977-986 (1993))
Present technique of monitoring blood glucose
Either invasive or minimally invasive
Being off-line methods-Time consumingLabour intensive
May not reflect real-time status of the glucosecan cause cell contamination
Shortcomings of invasive method
Painful
High recurring cost
Potential source of spread of diseases like Hepatitis,
HIV through contact with bodily fluids
Continuous monitoring not possible
Why non-invasive method ?
Will remove all shortcomings of present techniques
Improve quality of life
Reduce complications and mortality associated withthe disease
Possibility of developing artificial pancreas
Potential non-invasive optical methods
Infrared and Near-infrared absorption spectroscopy
Near-infrared scattering technique
Polarimetry technique
Raman spectroscopy
Photoacoustic spectroscpy
Photoacoustic MethodModulated laser beam
Excited state
Pressure wave
Acoustic transducer
AbsorptionAbsorption
of light
Sample
Radiative
transitionNon-radiative
transition
Ground state
Ah A
A Aheat
Factors affecting PA generation
Optical absorption coeff.
RadiativeRelaxation
Flourescence,Phosphorescence
Nanosecond PulsedLaser Beam
Wavelength
Pulse Width, PRFSkin and Tissue
Local Absorptionglucose molecules
Local Temperature E i a d
Ei : Incident optical energyμa : Absorption coefficient
d : Length of the cylinder within the sampleoccupied by the optical beam
Cp : Specific heat capacity for a constant pressureρ: Density of the medium
V : Illuminated volume at room temperaturer: Radius of the optical beam
β : Volumetric thermal expansion coefficient ofIncrease T
Specific heat capacity C p VVol. expansion coeff.
AdiabaticExpansion V TV
Pressure Wave
the medium
T : Rise in temperature
B : Bulk modulus
v : Speed of sound in the medium
2
Speed of sound
v B/
EiadGeneration p B t B
CpVTransducer type &
Pressure DetectionTransducer Dimension
v
Cp
Eia 2 r
Dependence of PA signal on glucose
concentration
Δp
2βv
Cp
Eμi a2
πr
Offers higher detection sensitivity with simple apparatus
More immune to scattering
Phases of development
The total development process has been planned intwo phases
Phase I
Validation of the technique with glucose solution
Phase IIApplication on human subject
Block diagram of the proposed non-invasive blood glucose monitoring system
Pulse Driver
Generator Circuit
Laser
Diode
Piezoelectric
Transducer
Low Noise
Amplifier
DIGITAL SIGNAL PROCESSING BLOCKS
Analog toSignal Fast FourierDigital Peak
DigitalAverager Transform DetectorConverter
Calibration
Disply
Correction
Factors
System Photograph
Choice of components
Acoustic signal detector Sensitive
Rugged Insensitive to changes in ambient conditions
Choice of wavelength
905 nm
905nm
905 nm wavelength gives desired depth of penetration and absorption byWater and other constitutes of blood are less compared to glucose.
Absorption profile of glucose
CGG
M 1
Comparison between 905 nm and 1064 nm
Parameter 905 nm 1064 nm
Absorption in tissue Slightly higher than Lower than atat 1064nm 905nm
Reduced scattering coefficient Low Almost equal
Effective penetration depth Second highest Highest(2.5mm) (3.5mm)
Absorption in water 0.007 mm-1 0.015mm-1
Absorption in glucose Low Very high
Sensitivity to oxy-hemoglobin Less Highand deoxy-hemoglobin
Power output of laser diode 90 watt 2 watt
Optical source and acoustic detector
Optical sourcePulsed Laser diode having λ = 905 nm
Model - PGAS1S12 from EG&G OptoelectronicsPulse width : ~100 ns
Pulse repetition frequency : ~100 HzPulse energy : Less than 0.1 μ J/Sq. cm.
Acoustic DetectorPiezoelectric material (PZT-5A) from Panametrics, USA
Transducer selection table
LiNbO3 PZT-5A PVDF
Piezoelectricd33 (10-12 C/N) 6 400 .39~.44constant
g33 (Vm/N) 0.023 0.025 -0.32
Mechanical Q factor 100 75 5~10
Density(g/cm3) 4.64 7650 1.78
Sound velocity (m/s) 7316 4500 2260
Acoustic impedance(106 33 35 4kg/m2s)
Work temperature(0C) <1100 <360 <60
Advantages Wide band, Inexpensive, Wide band,rugged High Inexpensive
sensitivity
Disadvantages Expensive Ringing Non-rugged
Application on human bodyMeasuring glucose from human body is quite complex due to wide
range of potentially interfering components. A number of factorsthat are to be considered for developing such a system :
a) Optical signal : Depth of penetration at least upto dermis layer of skin
Higher absorption by glucose compared to other constitutes ofblood, water, protein, fat, melanin etc.
Optical energy within the Maximum Permissible Engergy (MPE) asspecified in ‘Safe use of lasers for health care facilities, - ANSIStandard Z 136.3-2005’
Pulse width and pulse repetition frequency meeting PA generationcondition.
Test site (e.g. finger, earlobe etc.) Optical signal delivery mechanism
Phase-I : Glucose solution
Carried out PA measurement at 1064 nm usingNd:YAG laser with glucose solution of differentconcentrations
Result : Peak-to-peak value of the PA signal maintains a nearly linearrelationship with the concentration of glucose in the solution.
Conclusion : Can be considered for developing a non-invasive bloodglucose monitor
Phase II: on human subject with OGTT
0.8
0.7
0.6
0.5
0.4
0.3 Point of drinking
0.2
0.1
00 5 10 15 20 25 30 35 40
Time (minute)
Variation of PA signal plotted with digitized signal captured through oscilloscope
Finding : Result closely matches the pattern of variation after consumptionof glucose by a subject with the result reported in the literature
Variation of PA amplitude with glucoseconcentration
80
79
78
77
76
75
74
73
72
71
70100 105 110 115 120 125 130 135 140Blood glucose level in mg/dl
Blood glucose values measured with SMBG monitor ACCU CHEK Active
Further work needed to realize the system
Although results achieved so far are quite encouraging, but needsfurther extensive testing and improvement in the design before it canbe considered for clinical use.
Modification of the front-end circuitry Design of laser driver circuit
Development of Signal Processing Algorithms and implementationin FPGA
Nullify the sources of error due to change in Pressure
Temperature (both ambient and body) Melanin content of the skin
Oxygen saturation of blood Subject dependent tissue condition at the test site (finger) Any other physiological conditions
BIBLIOGRAPHY
1. Amos AF, McCarty DJ & Zimmett P (1997) The rising global burden of diabetes and its complications: estimates and projections to the year 2010. Diabetic Medicine, Supplement 5: S1-S5.
2. Lahmann W, Ludewig HJ, & Welling H (1977) Opto acoustic trace analysis in liquids with the frequency modulated beam of an Argon ion laser. Analytical Chemistry 49: 549-551.
3. Oda S, Sawada T & Kamada H (1978) Determination of ultra trace Cadmium by laser-induced photoacoustic absorption spectroscopy. Analytical Chemistry 50: 865 867.
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