module 1.1: overview of the laser breast scanner

Module 1.1:Overview of the

Laser Breast Scanner

Albert Cerussi

Beckman Laser InstituteUniversity of California, Irvine

http://www.bli.uci.edu/lammp

NTROI DOS Workshop, 2007 Module 1.1

Module Goal

• Basic hardware and models used in the Laser Breast Scanner

• Detail for each step covered in other modules

• Assumes basic knowledge of diffuse optics



Outline• Overview

• Diffuse Optical Models

• LBS Hardware

• LBS Data acquisition



Overview• tissue spectroscopy

• uses handheld probe

• similar to an ultrasound

• Diffuse Optical Spectroscopy



• tissue spectroscopy




Overview






• Diffuse Optical Spectroscopy650 700 750 800 850 900 950 1000

0.0

0.2

0.4

0.6

0.8

1.0

EXTI

NCTI

ON

(mm

-1 m

M -1

)WAVELENGTH (nm)

ctHHb (deoxy hemoglobin)

ctO2Hb (oxy hemoglobin)

ctH2O (water)

bulk lipids



Overview

Y

X

RIGHT



LBS Technology/Models

Frequency-domain– Modulated laser diodes– Multi-frequency– Single distance– Discrete (6 )– Absolute optical properties

Steady-State– Tungsten-Halogen lamp– Steady-state– Single distance– Broadband (650-1000nm)– Relative optical spectra

• frequency-domain and steady-state spectroscopies



DOS Models: FDPM

)31(1)(2 Dvi

Dk a

a

a

Fishkin, J. B., Fantini, S., Vandeven, M. J. and Gratton, E., "Gigahertz photon density waves in a turbid medium: Theory and experiments," Phys. Rev. E, 53, pp. 2307-19, 1996.

rkrvD

iSrU )(exp14

)](exp[)(),( 0

P1 Approximation to the Transport Equation:

Cerussi, A. and Tromberg, B., "Photon migration spectroscopy: Frequency domain techniques," in Biomedical photonics handbook, Vo-Dinh, T., Ed., 1st ed.: CRC Press, 2003, pp. 22.1-.17.

Infinite medium

Wave vector

)'(3 sa

vvD

Optical diffusion



DOS Models: FDPM

j

jeff RR

RRR

2

2/

0)()cos()sin(2

FresnelRdR

treff

effb l

RR

z

11

32

Haskell, R. C., Svaasand, L. O., Tsong-Tseh, T., Ti-Chen, F., Mcadams, M. S. and Tromberg, B. J., "Boundary conditions for the diffusion equation in radiative transfer," J. Opt. Soc. Am. A, 11, pp. 2727-41, 1994.

Boundary Condition (semi-infinite)

Partial current/Extrapolated Boundary condition

2/

0

2 )()(cos)sin(3

Fresnelj RdR

Effective source depth



DOS Models: FDPM

22

4)(),(

vD

SAsi

brealb

bimagrealo

rkr

rrkrkr 0

0000 )(exp1))((cos)(exp1

brealb

bimag rkr

rrk 00

00 )(exp1))((sin

)(arctan)(),( 00

rk imagsi

From the photon density:

Photon density amplitude

Photon density phase

where …

Cerussi, A. and Tromberg, B., "Photon migration spectroscopy: Frequency domain techniques," in Biomedical photonics handbook, Vo-Dinh, T., Ed., 1st ed.: CRC Press, 2003, pp. 22.1-.17.



DOS Models: SS

)cos()cos(),(

3),()(141),(

2

dztr

DtrRdtrR surfsurfFresnel

),(306.0),(118.0),( trRtrtrR fsurf

Kienle, A. and Patterson, M. S., "Improved solutions of the steady-state and the time-resolved diffusion equations for reflectance from a semi-infinite turbid medium," J Opt Soc Am A, 14, pp. 246-54, 1997.

Reflectance

for n=1.4

fluence flux



LBS HardwareNETWORK ANALYZER

S R A

BRIDGE

RF SWITCH

T

T

T

T

T

T

DC SOURCE

SPECTROMETER

APD

LAMP

HANDPIECE

TISSUE



LBS HardwareEach method calibrated separately

1. Frequency-domain– unknown source terms (S(), 0())– phantom of known optical properties

2. Steady-state– unknown spectral response– ideal reflector with known spectral response



LBS HardwareWARNING!

It is essential that these calibrations are performed properly.

- data quality compromised - data may be useless



LBS Data Acquisition

modulation

0 20 40 60 80 100

0.0

0.5

1.0

1.5

2.0

INTE

NSIT

Y

TIME (s)

50 MHz

~ 1 ms




modulation

0 20 40 60 80 100

0.0

0.5

1.0

1.5

2.0

INTE

NSIT

Y

TIME (s)

50 MHz

~ 1 ms201 frequency sweep

0 20 40 60 80 100

0.0

0.5

1.0

1.5

2.0

INTE

NSIT

Y

TIME (s)

100 MHz




modulation

0 20 40 60 80 100

0.0

0.5

1.0

1.5

2.0

INTE

NSIT

Y

TIME (s)

50 MHz

~ 1 ms

0 20 40 60 80 100

0.0

0.5

1.0

1.5

2.0

INTE

NSIT

Y

TIME (s)

100 MHz

201 frequency sweep

50-500 MHz(~ 200 ms)




100 200 300 400 500

FREQUENCY (MHz)

20

40

60

80

100

120

140

160

180

PHA

SE (d

eg)

100 200 300 400 500

1.5

2.0

2.5

3.0

3.5

4.0

4.5

AMPL

ITUD

E (a

.u.)

FREQUENCY (MHz)

modulation

diffusion model




100 200 300 400 500

FREQUENCY (MHz)

20

40

60

80

100

120

140

160

180

PHA

SE (d

eg)

100 200 300 400 500

1.5

2.0

2.5

3.0

3.5

4.0

4.5

AMPL

ITUD

E (a

.u.)

FREQUENCY (MHz)

modulation

diffusion model

global fit




100 200 300 400 500

FREQUENCY (MHz)

20

40

60

80

100

120

140

160

180

PHA

SE (d

eg)

100 200 300 400 500

1.5

2.0

2.5

3.0

3.5

4.0

4.5

AMPL

ITUD

E (a

.u.)

FREQUENCY (MHz)

modulation

diffusion model

global fit

optical properties




650 700 750 800 850 900 950 10000.000

0.003

0.006

0.009

0.012

ABSO

RPTI

ON

(mm

-1 )

WAVELENGTH (nm)

modulation

absorption &scattering

diffusionmodel

650 700 750 800 850 900 950 10000.5

0.6

0.7

0.8

0.9

1.0

1.1

SCAT

TERI

NG (m

m-1)

WAVELENGTH (nm)




650 700 750 800 850 900 950 10000.000

0.003

0.006

0.009

0.012

ABSO

RPTI

ON

(mm

-1 )

WAVELENGTH (nm)

modulation


diffusionmodel

650 700 750 800 850 900 950 10000.5

0.6

0.7

0.8

0.9

1.0

1.1

SCAT

TERI

NG (m

m-1)

WAVELENGTH (nm)

power law

SPSAscattering




650 700 750 800 850 900 950 10000.000

0.003

0.006

0.009

0.012

ABSO

RPTI

ON

(mm

-1 )

WAVELENGTH (nm)

modulation


diffusionmodel

650 700 750 800 850 900 950 1000

2

4

6

8

10

REFL

ECTA

NCE

(a.u

.)

WAVELENGTH (nm)

broadbandreflectance




650 700 750 800 850 900 950 10000.000

0.003

0.006

0.009

0.012

ABSO

RPTI

ON

(mm

-1 )

WAVELENGTH (nm)

modulation


diffusionmodel

650 700 750 800 850 900 950 1000

2

4

6

8

10

REFL

ECTA

NCE

(a.u

.)

WAVELENGTH (nm)


scale w FDPM




modulation


diffusionmodel


650 700 750 800 850 900 950 10000.000

0.003

0.006

0.009

0.012 FDPM BROADBAND FOUR COMPONENT FIT

ABSO

RPTI

ON

(mm

-1 )

WAVELENGTH (nm)




modulation


diffusionmodel


650 700 750 800 850 900 950 10000.000

0.003

0.006

0.009

0.012 FDPM BROADBAND FOUR COMPONENT FIT

ABSO

RPTI

ON

(mm

-1 )

WAVELENGTH (nm)

chromophore fit


module 1.1: overview of the laser breast scanner

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