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Designing and implementing bioimpedance spectroscopy device by measuring impedance in a mouse tissue.

Dastjerdi HM, Soltanzadeh R, Rabbani H - J Med Signals Sens (2013)

Bottom Line: Studies show that any complications including hemorrhage, lack of blood supply, lack of oxygen supply and death of cells in a tissue, will have a clear effect on electrical properties of that tissue.Thus, by measuring impedance of a set of tissues, potential problems of the damaged tissue may be found.Thus, with this hardware created, it shows that there are significant impedance changes between mouse tissues.

View Article: PubMed Central - PubMed

Affiliation: Medical Image and Signal processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.

ABSTRACT
Studies show that any complications including hemorrhage, lack of blood supply, lack of oxygen supply and death of cells in a tissue, will have a clear effect on electrical properties of that tissue. Thus, by measuring impedance of a set of tissues, potential problems of the damaged tissue may be found. Since electrical impedance is closely related to the measuring frequency, obviously, every tissue exhibits its own specific impedance according to its electrical properties at each frequency. This research project investigates design and manufacture method of a device for measuring tissue impedance at different frequencies. To this end, design of a multi frequency sinusoidal current source is required. This current source is built using a single harmonic Generator sample (Direct Digital Synthesizer AD9835) with working frequency (design-point frequency) between 1 Hz and 10 MHz and accuracy of 1 Hz and microcontroller (PIC16F628) capability. For measurement and display of tissue impedance, ARM AT91SAMs256 microcontroller was used. Thus, with this hardware created, it shows that there are significant impedance changes between mouse tissues.

No MeSH data available.


Howland circuit current source
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Figure 5: Howland circuit current source

Mentions: According to Frick and Morris, impedance is a highly dependent on the applied current frequency. Thus, a constant current source is needed to ensure detection of the each smallest effect of tissue impedance on the current supply. The ideal current source is a source with near zero output impedance. This wave is sinusoidal and to reduce common mode voltage, it must be symmetrical with earth and its offset voltage must be zero. For this purpose, this current source is built using the Direct Digital Synthesizer (DDS) AD9835 and a voltage/current converter. Current source building methods are based on (1) using current mirror, (2) using Op-Amp and (3) improved current source known as Howland circuit. In this study, Howland circuit current source was used [Figure 5].


Designing and implementing bioimpedance spectroscopy device by measuring impedance in a mouse tissue.

Dastjerdi HM, Soltanzadeh R, Rabbani H - J Med Signals Sens (2013)

Howland circuit current source
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3959010&req=5

Figure 5: Howland circuit current source
Mentions: According to Frick and Morris, impedance is a highly dependent on the applied current frequency. Thus, a constant current source is needed to ensure detection of the each smallest effect of tissue impedance on the current supply. The ideal current source is a source with near zero output impedance. This wave is sinusoidal and to reduce common mode voltage, it must be symmetrical with earth and its offset voltage must be zero. For this purpose, this current source is built using the Direct Digital Synthesizer (DDS) AD9835 and a voltage/current converter. Current source building methods are based on (1) using current mirror, (2) using Op-Amp and (3) improved current source known as Howland circuit. In this study, Howland circuit current source was used [Figure 5].

Bottom Line: Studies show that any complications including hemorrhage, lack of blood supply, lack of oxygen supply and death of cells in a tissue, will have a clear effect on electrical properties of that tissue.Thus, by measuring impedance of a set of tissues, potential problems of the damaged tissue may be found.Thus, with this hardware created, it shows that there are significant impedance changes between mouse tissues.

View Article: PubMed Central - PubMed

Affiliation: Medical Image and Signal processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.

ABSTRACT
Studies show that any complications including hemorrhage, lack of blood supply, lack of oxygen supply and death of cells in a tissue, will have a clear effect on electrical properties of that tissue. Thus, by measuring impedance of a set of tissues, potential problems of the damaged tissue may be found. Since electrical impedance is closely related to the measuring frequency, obviously, every tissue exhibits its own specific impedance according to its electrical properties at each frequency. This research project investigates design and manufacture method of a device for measuring tissue impedance at different frequencies. To this end, design of a multi frequency sinusoidal current source is required. This current source is built using a single harmonic Generator sample (Direct Digital Synthesizer AD9835) with working frequency (design-point frequency) between 1 Hz and 10 MHz and accuracy of 1 Hz and microcontroller (PIC16F628) capability. For measurement and display of tissue impedance, ARM AT91SAMs256 microcontroller was used. Thus, with this hardware created, it shows that there are significant impedance changes between mouse tissues.

No MeSH data available.