Valchinov & Pallikarakis laser prototype

[Guest guest]

Hi Tym & All,

 

Tym wrote:

> This reads like they are advertising their product, doesn't seem to be

> anything new here that hasn't been addressed with the myriad of other

> products on the market.

 

Tym, Drs Valchinov & Pallikarakis may be advertising (in that most

researchers / scientists publish their work), but they are NOT selling

anything. Their instruments are research prototypes and are NOT for

sale commercially.

 

Drs V & P are researchers working in Dept of Medical Physics,

University of Patras, Greece. Their research is on new instrumentation

for biomedical lasers and an active electrode for biopotential recording

from small localized bio-sources.

 

Their research is published in Biomed Eng Online, which is a peer-

reviewed open-source online journal, founded in 2002. See:

http://www.biomedical-engineering-online.com/info/about/

 

See their two abstracts, below, from PubMed Medline.

 

 

1: Biomed Eng Online. 2005 Jan 13;4(1):5. Related Articles, Links

Design and testing of low intensity laser biostimulator. Valchinov ES,

Pallikarakis NE. Department of Medical Physics, University of Patras,

Patras 26500, Greece. emil BACKGROUND: The

non-invasive nature of laser biostimulation has made lasers an

attractive alternative in Medical Acupuncture at the last 25 years.

However, there is still an uncertainty as to whether they work or their

effect is just placebo. Although a plethora of scientific papers published

about the topic showing positive clinical results, there is still a lack of

objective scientific proofs about the biostimulation effect of lasers in

Medical Acupuncture. The objective of this work was to design and

build a low cost portable laser device for stimulation of acupuncture

points, considered here as small localized biosources (SLB), without

stimulating any sensory nerves via shock or heat and to find out a

suitable method for objectively evaluating its stimulating effect. The

design is aimed for studying SLB potentials provoked by laser stimulus,

in search for objective proofs of the biostimulation effect of lasers used

in Medical Acupuncture. METHODS: The proposed biostimulator

features two operational modes: program mode and stimulation mode

and two output polarization modes: linearly and circularly polarized laser

emission. In program mode, different user-defined stimulation protocols

can be created and memorized. The laser output can be either

continuous or pulse modulated. Each stimulation session consists of a

pre-defined number of successive continuous or square pulse

modulated sequences of laser emission. The variable parameters of the

laser output are: average output power, pulse width, pulse period, and

continuous or pulsed sequence duration and repetition period. In

stimulation mode the stimulus is automatically applied according to the

pre-programmed protocol. The laser source is 30 mW AlGaInP laser

diode with an emission wavelength of 685 nm, driven by a highly

integrated driver. The optical system designed for beam collimation and

polarization change uses single collimating lens with large numerical

aperture, linear polarizer and a quarter-wave retardation plate. The

proposed method for testing the device efficiency employs a

biofeedback from the subject by recording the biopotentials evoked by

the laser stimulus at related distant SLB sites. Therefore measuring of

SLB biopotentials caused by the stimulus would indicate that a

biopotential has been evoked at the irradiated site and has propagated

to the measurement sites, rather than being caused by local changes of

the electrical skin conductivity. RESULTS: A prototype device was built

according to the proposed design using relatively inexpensive and

commercially available components. The laser output can be pulse

modulated from 0.1 to 1000 Hz with a duty factor from 10 to 90%. The

average output power density can be adjusted in the range 24-480

mW/cm2, where the total irradiation is limited to 2 Joule per stimulation

session. The device is controlled by an 8-bit RISC Flash microcontroller

with internal RAM and EEPROM memory, which allows for a wide range

of different stimulation protocols to be implemented and memorized.

The integrated laser diode driver with its onboard light power control

loop provides safe and consistent laser modulation. The prototype was

tested on the right Tri-Heater (TH) acupuncture meridian according to

the proposed method. Laser evoked potentials were recorded from

most of the easily accessible SLB along the meridian under study. They

appear like periodical spikes with a repetition rate from 0.05 to 10 Hz

and amplitude range 0.1-1 mV. CONCLUSION: The prototype's

specifications were found to be better or comparable to those of other

existing devices. It features low component count, small size and low

power consumption. Because of the low power levels used the

possibility of sensory nerve stimulation via the phenomenon of shock or

heat is excluded. Thus senseless optical stimulation is achieved. The

optical system presented offers simple and cost effective way for beam

collimation and polarization change. The novel method proposed for

testing the device efficiency allows for objectively recording of SLB

potentials evoked by laser stimulus. Based on the biopotential records

obtained with this method, a scientifically based conclusion can be

drawn about the effectiveness of the commercially available devices for

low-level laser therapy used in Medical Acupuncture. The prototype

tests showed that with the biostimulator presented, SLB could be

effectively stimulated at low power levels. However more studies are

needed to derive a general conclusion about the SLB biostimulation

mechanism of lasers and their most effective power and optical

settings. PMID: 15649327 [PubMed - in process] Best regards,

Phil

 

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Valchinov ES, Pallikarakis NE. Design and testing of low intensity laser

biostimulator. (2005) Biomed Eng Online. Jan 13;4(1):5. Department

of Medical Physics, University of Patras, Patras 26500, Greece.

emil BACKGROUND: The non-invasive nature of

laser biostimulation has made lasers an attractive alternative in Medical

Acupuncture at the last 25 years. However, there is still an uncertainty

as to whether they work or their effect is just placebo. Although a

plethora of scientific papers published about the topic showing positive

clinical results, there is still a lack of objective scientific proofs about the

biostimulation effect of lasers in Medical Acupuncture. The objective of

this work was to design and build a low cost portable laser device for

stimulation of acupuncture points, considered here as small localized

biosources (SLB), without stimulating any sensory nerves via shock or

heat and to find out a suitable method for objectively evaluating its

stimulating effect. The design is aimed for studying SLB potentials

provoked by laser stimulus, in search for objective proofs of the

biostimulation effect of lasers used in Medical Acupuncture.

METHODS: The proposed biostimulator features two operational

modes: program mode and stimulation mode and two output

polarization modes: linearly and circularly polarized laser emission. In

program mode, different user-defined stimulation protocols can be

created and memorized. The laser output can be either continuous or

pulse modulated. Each stimulation session consists of a pre-defined

number of successive continuous or square pulse modulated

sequences of laser emission. The variable parameters of the laser

output are: average output power, pulse width, pulse period, and

continuous or pulsed sequence duration and repetition period. In

stimulation mode the stimulus is automatically applied according to the

pre-programmed protocol. The laser source is 30 mW AlGaInP laser

diode with an emission wavelength of 685 nm, driven by a highly

integrated driver. The optical system designed for beam collimation and

polarization change uses single collimating lens with large numerical

aperture, linear polarizer and a quarter-wave retardation plate. The

proposed method for testing the device efficiency employs a

biofeedback from the subject by recording the biopotentials evoked by

the laser stimulus at related distant SLB sites. Therefore measuring of

SLB biopotentials caused by the stimulus would indicate that a

biopotential has been evoked at the irradiated site and has propagated

to the measurement sites, rather than being caused by local changes of

the electrical skin conductivity. RESULTS: A prototype device was built

according to the proposed design using relatively inexpensive and

commercially available components. The laser output can be pulse

modulated from 0.1 to 1000 Hz with a duty factor from 10 to 90%. The

average output power density can be adjusted in the range 24-480

mW/cm2, where the total irradiation is limited to 2 Joule per stimulation

session. The device is controlled by an 8-bit RISC Flash microcontroller

with internal RAM and EEPROM memory, which allows for a wide range

of different stimulation protocols to be implemented and memorized.

The integrated laser diode driver with its onboard light power control

loop provides safe and consistent laser modulation. The prototype was

tested on the right Tri-Heater (TH) acupuncture meridian according to

the proposed method. Laser evoked potentials were recorded from

most of the easily accessible SLB along the meridian under study. They

appear like periodical spikes with a repetition rate from 0.05 to 10 Hz

and amplitude range 0.1-1 mV. CONCLUSION: The prototype's

specifications were found to be better or comparable to those of other

existing devices. It features low component count, small size and low

power consumption. Because of the low power levels used the

possibility of sensory nerve stimulation via the phenomenon of shock or

heat is excluded. Thus senseless optical stimulation is achieved. The

optical system presented offers simple and cost effective way for beam

collimation and polarization change. The novel method proposed for

testing the device efficiency allows for objectively recording of SLB

potentials evoked by laser stimulus. Based on the biopotential records

obtained with this method, a scientifically based conclusion can be

drawn about the effectiveness of the commercially available devices for

low-level laser therapy used in Medical Acupuncture. The prototype

tests showed that with the biostimulator presented, SLB could be

effectively stimulated at low power levels. However more studies are

needed to derive a general conclusion about the SLB biostimulation

mechanism of lasers and their most effective power and optical

settings. PMID: 15649327 [PubMed - in process]

 

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

 

Valchinov ES, Pallikarakis NE. (2004) An active electrode for

biopotential recording from small localized bio-sources. Biomed Eng

Online. Jul 22;3(1):25. Department of Medical Physics, University of

Patras, Patras 26500, Greece. emil

BACKGROUND: Laser bio-stimulation is a well-established procedure

in Medical Acupuncture. Nevertheless there is still a confusion as to

whether it works or the effect is just placebo. Although a plethora of

scientific papers published, showing positive clinical results, there is still

a lack of objective scientific proofs about the bio-stimulation effect of

lasers used in Acupuncture. The objective of this work was to design

and build a body surface electrode and an amplifier for biopotential

recording from acupuncture points, considered here as small localized

bio-sources (SLB). The design is aimed for studying SLB potentials

provoked by laser stimulus, in search for objective proofs of the bio-

stimulation effect of lasers used in Medical Acupuncture. METHODS:

The active electrode presented features a new adjustable anchoring

system and fractionation of the biopotential amplifier between the

electrode and the cabinet's location. The new adjustable electrode

anchoring system is designed to reduce the electrode-skin contact

impedance, its variation and motion artifacts. That is achieved by

increasing the electrode-skin tension and decreasing its relative

movement. Additionally the sensing element provides local constant

skin stretching thus eliminating the contribution of the skin potential

artifact. The electrode is attached to the skin by a double-sided

adhesive pad, where the sensing element is a stainless steel, 4 mm in

diameter. The fractionation of the biopotential amplifier is done by

incorporating the amplifier's front-end op-amps at the electrodes, thus

avoiding the use of extra buffers. The biopotential amplifier features two

selectable modes of operation: semi-AC-mode with a -3 dB bandwidth

of 0.32-1000 Hz and AC-mode with a bandwidth of 0.16-1000 Hz.

RESULTS: The average measured DC electrode-skin contact

impedance of the proposed electrode was 450 kOmega, with electrode

tension of 0.3 kg/cm2 on an unprepared skin of the inner forearm. The

peak-to-peak noise voltage measured at the amplifier output, with input

terminals connected to common, was 10 mVp-p, or 2 microVp-p

referred to the input. The common-mode rejection ratio of the amplifier

was 96 dB at 50 Hz, measured with imbalanced electrodes'

impedances. The prototype was also tested practically and sample

records were obtained after a low intensity SLB laser stimulation. All

measurements showed almost a complete absence of 50 Hz

interference, although no electrolyte gel or skin preparation was applied.

CONCLUSION: The results showed that the new active electrode

presented significantly reduced the electrode-skin impedance, its

variation and motion artifact influences. This allowed SLB signals with

relatively high quality to be recorded without skin preparation. The

design offers low noise and major reduction in parts, size and power

consumption. The active electrode specifications were found to be

better or at least comparable to those of other existing designs. PMID:

15271219 [PubMed - indexed for MEDLINE]

 

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