The SOLUS project: Smart optical and ultrasound diagnostics of breast cancer - Paola Taroni and the SOLUS Consortium
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The SOLUS project:
Smart optical and ultrasound diagnostics of breast cancer
Paola Taroni
Politecnico di Milano, Dipartimento di Fisica
and the SOLUS Consortium
Background (I)
• Breast cancer
The most common cancer in women in Europe and worldwide
(more than 2 million new cases diagnosed in 2020) [GLOBOCAN 2020]
About 1 in 8 women in Europe and US will be diagnosed with breast
cancer in the course of her lifetime
• Role of early diagnosis
Mammographic screening reduces breast-cancer mortality: ranging from
28% to 35% [Nelson et al, Ann Intern Med, 2016]
paola.taroni@polimi.it www.solus-project.eu 2
Background (II)
• Limitations of screening mammography
Detection of previously occult benign breast lesions
The cumulative risk of a false-positive mammogram over a 10-year
period of yearly screening reaches 50-60%
• Consequences
Needless additional imaging and invasive procedures
Negative impact on the patient’s quality of life
High burden for the healthcare systems
paola.taroni@polimi.it www.solus-project.eu 3
General goal of the project
To support the in vivo diagnosis of breast cancer improving the
discrimination of lesions that are borderline between benign
and malignant lesions
Patients’ quality of life
Sustainability of the healthcare systems
paola.taroni@polimi.it www.solus-project.eu 4
“Technical” objectives towards the general goal
• Main objective
Develop an innovative multi-modal tomographic system combining
ultrasound and optical imaging
Breast imaging Medical imaging
• Specific/intermediate objective
Develop an innovative, ground-breaking, low-cost, small size photonic module
– the Smart Optode - to perform in depth diffuse optical measurements
Non diagnostic medical applications
Other fields
paola.taroni@polimi.it www.solus-project.eu 5SOLUS concept
SSI Aixplorer Mach30™
B-mode US • Morphology Multi-
parametric
analysis
US guidance
Shear Wave
Elastography
• Stiffness
MORE SPECIFIC
NON-INVASIVE
Diffuse Optical • Composition DIAGNOSIS OF
Tomography • Physiology BREAST CANCER
SOLUS project • Blood volume • Water
• Oxygen saturation • Lipids
• Collagen
paola.taroni@polimi.it www.solus-project.eu 6Time domain diffuse optical spectroscopy
• Effects of light propagation Laser Reflectance
pulse
Attenuation mm-cm
Delay
Broadening
laser pulse
1.000
TRSLaser
dataPulse
Model
model
TR data
(a.u.)
Intensity (a.u.)
0.100
intensity
0.010
Transmittance
0.001
0 1000 2000 3000 4000 5000
Time(ps)
time (ps)
• Theoretical model:
Diffusion approximation to Radiative Transport
Absorption coefficient Tissue composition
Scattering coefficient Tissue structure
paola.taroni@polimi.it www.solus-project.eu 7Absorption spectra and tissue composition
Water
0.35
Beer’s law
a i ci i
0.30
• OxyHb Fibrous
absorption (cm-1)
0.25
• DeoxyHb
0.20 • Water
• Lipids
0.15 • Collagen
Adipose
0.10
0.05
Lipid
0.00
600 650 700 750 800 850 900 950 1000 1050 1100
wavelength (nm)
8Scattering spectra and tissue structure
25
Empirical approximation to Mie theory
Fibrous
bFM-50
PT-40'DC-29 EL-34 LT-23
6.8a11.7
T KE-31
a s 8.9
9.3 11.0 9.6
b 2.0 1.4 2.0 0.7 0.7 0.7
20
a density of scatterers
reduced scattering (cm-1)
b equivalent size of scatterers
Adipose 15
10
5
0
600 650 700 750 800 850 900 950 1000 1050
wavelength (nm)
9Multi-modal tomographic probe
US transducer (5.5 x 0.8 cm2)
Smart optode (1 x 1 cm2)
(x8)
paola.taroni@polimi.it www.solus-project.eu 10Diffuse Optics in SOLUS
• Time domain
0.35 25
T PT-40 DC-29 EL-34 LT-23 FM-50 KE-31
a 9.3 8.9 6.8 11.7 11.0 9.6
0.30 b 2.0 1.4 2.0 0.7 0.7 0.7
20
reduced scattering (cm-1)
absorption (cm-1)
0.25
15
0.20
To uncouple absorption from scattering 0.15
0.10
10
5
0.05
Time domain detector 0.00
600 650 700 750 800 850 900 950 1000 1050 1100
0
600 650 700 750 800 850
wavelength (nm)
900 950 1000 1050
wavelength (nm)
• Multiple wavelengths
To estimate Hb, HbO2, water, lipids, collagen
Broad spectral range (635-1064 nm)
• Tomographic approach
To identify to region of interest and improve quantification
Time-gated wide-area detector
5.5 cm
paola.taroni@polimi.it www.solus-project.eu 11State of the art of time domain diffuse optics
2015: 600-1350 nm
single point
2020: 8 wavelengths
2017: 8 wavelengths tomographic
2 channels
600-1350 nm
125 cm
m3 dm3 cm3
DEVICE SIZE
paola.taroni@polimi.it www.solus-project.eu 12Timeline
• Picosecond pulsed laser driver
• Wide area gated SiPM detector
• Dedicated acquisition electronics
Optode Multimodal
Single optode Clinical validation
components probe & system
Developed and validated Integrated and Start in
in laboratory settings under characterization Summer 2021
paola.taroni@polimi.it www.solus-project.eu 13Multiple wavelength picosecond pulsed lasers
• Integrated dual-channel Laser Driver
Tunable pulse-width and delay with 1 ps steps
Tested up to 80 MHz repetition frequency
• 8 wavelength lasers
Specifically selected (635-1064 nm)
• Resulting performances
FWHM < 240 ps
Output power: between 1.5 and 6 mW
Negligible exponential tail or secondary peaks
paola.taroni@polimi.it www.solus-project.eu 14Fast-gated dSiPM with integrated TDC
• Digital SiPM
- Photon collection area: 4.9 × 4.7 mm2
- Controllable active area: up to 8.6 mm2
hot-pixel shutdown lower noise
signal equalization
- Gate-on transition:The smart optode
Ultra-compact system for time domain multi-wavelength DOT
• Responsivity: >106 m2sr @600 nm for an active area of 2 mm2
10x larger than for state-of-the-art systems
• Retrieval of optical properties (homogeneous medium)
(a = 0.06-0.4 cm-1 and reduced scattering s’ = 4-17 cm-1)
Relative error on Absorption: 10% (median)
− Relative error on Scattering: up to 40%
• Sensitivity to deep absorption perturbations
Δμa = 0.16 cm-1, 1 cm3, embedded in bkg medium (a = 0.1 cm-1 and s’ = 10 cm-1)
Sensitivity: down to 3.5 cm with 2% contrast
paola.taroni@polimi.it www.solus-project.eu 16The multi-modal SOLUS system
Mach 30
SOLUS screen
Calibration and screen
performance 3D position
sensor
assessment on-going
SOLUS standard
probe US probe
cooling
system
Mach 30
body
3D position
bay
medical grade
power supply
paola.taroni@polimi.it www.solus-project.eu 17Next steps
Clinical validation of the SOLUS system
• 3 radiologists
• “Mock sessions”
Train medical doctors
Test the system usability and ergonomics
• Pilot clinical feasibility study
20 benign (BIRADS 2-3) and 20 malignant (BIRADS 4-5) lesions
Smart optode
• Investigate the optode potential
Development of wearable devices (medical, sport, rehabilitation fields)
Use in other fields (e.g., fruit quality assessment)
paola.taroni@polimi.it www.solus-project.eu 18Thank you for your attention
Paola Taroni - paola.taroni@polimi.it
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 731877. The
project is an initiative of the Photonics Public Private Partnership.
www.solus-project.eu
www.photonics21.org
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