Optical fiber sensors for medical applications
Research activities at University of Limerick
[Jiliang University, 10 Dec 20...
About
University of Limerick
Optical Fibre Sensors Research Centre
[Marie Curie Fellow @ OFSRC]

Daniele Tosi - Optical fib...
Partnerships
Cleveland Clinic
EFPI cardiovascular/demo
Johns Hopkins
Robotic surgery

UL, OFSRC
Pointec (licensing)

Harbi...
Outline
➡ Optical fiber sensors: properties and technology
‣EFPI - pressure, temperature, refractive index
‣Fiber Bragg gra...
OFS properties
Top-notch
Performance
Miniature size
Distribution and
Integration
Immunity

➡ Excellent sensitivity to pres...
EFPI
EFPI: Fiber-optic Fabry-Perot interferometric sensor based on all-silica
glass structure: (1) launch fiber, (2) diaphr...
UL EFPI (pre-etch)
Air-gap length L
FP Spectrum ~ S0 + k cos[4πL/λ]

L = 20.6μm

Single-mode fiber

phragm
Dia
ir-gap
A

L
...
UL EFPI (pre-etch)

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Li...
UL EFPI (pre-etch)
Air-gap length L = L0 - Sp ΔP
FP Spectrum ~ S0 + k cos[4π(L - Sp ΔP)/λ]
Temperature: L = L0 - Sp ΔP + S...
Commercial EFPI
EFPI head: 200µm

Encapsulation: 500µm

Input fiber: 125µm

Daniele Tosi - Optical fiber sensors for medica...
Commercial EFPI

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limer...
Pressure detection
RMSE = 2.29 mmH2O

RMSE = 1.30 mmH2O

Daniele Tosi - Optical fiber sensors for medical applications - Re...
Pressure detection
RMSE = 2.29 mmH2O

RMSE = 2.29 mmH2O =
= 0.21 mmHg
RMSE = 1.30 mmH2O

Daniele Tosi - Optical fiber senso...
Improved detection

D. Tosi, S. Poeggel. G. Leen, E. Lewis, “Adaptive
filter-based interrogation of high-sensitivity fiber
o...
Fiber Bragg grating (FBG)

FBG = fiber optic filter
FBG cascade ⬌ Multiplexing
Daniele Tosi - Optical fiber sensors for medic...
Fiber Bragg grating (FBG)
•Information encoded in

FBG optical spectrum
•Linear dependance on
strain and temperature
•Top ...
Fiber Bragg grating (FBG)
Strain + temperature encoded in the sensing element

Strain: can be converted into force, by pac...
Draw-tower grating

IOS hypertermia sensor:
5 FBG in 3 cm

Daniele Tosi - Optical fiber sensors for medical applications - ...
Long period grating (LPG)

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at Universit...
EFPI/FBG

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
EFPI/FBG
Δλ(ΔT, ΔP)
ΔL(ΔT,ΔP)

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at Unive...
Cross-sensitivity
Detuning: 0.03 kPa/°C
-96% glass
-99.6% mould

Daniele Tosi - Optical fiber sensors for medical applicati...
White light setup
Courtesy of Politecnico di Torino

.
.
.

.
.
.

...
...
...

Switch
SLED
FBGA
Daniele Tosi - Optical fib...
White light setup
Courtesy of Politecnico di Torino

.
.
. FBGA

.
.
.

FBG matrix
...
...
.
.
.
...
SLED

Switch
SLED
FBG...
Coherent light setup
Courtesy of Politecnico di Torino

.
.
.

.
.
.

FBG matrix
...
...
.
.
.
...

Switch
Laser
controlle...
Circulator
Coherent light Switch
setup
Courtesy of Politecnico di Torino

.
.
.

Laser

FBG matrix
...
...
TEC
. Photodiod...
Interrogation
White light

Coherent light

Encoding

Wavelength

Amplitude

Resolution

1 pm (150 pm)

<< 1 pm

Throughput...
Further integration
➡ Lab in a fiber
‣Integration of several sensing units in a single fiber
‣FBG (array), LPG, EFPI + bio/c...
Pigtail catheter

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Lime...
Pigtail catheter
Contrast liquid

4F
2x probes (distal)

French(F) = 1/3mm

Excess bending

Daniele Tosi - Optical fiber se...
Foley catheter

Urology catheter, bi-sex
Daniele Tosi - Optical fiber sensors for medical applications - Research activitie...
Foley catheter
Seal: epoxy or medical tape

1cm
FO
Infusion + uroflowmetry

4F

Side holes
allow infusion

Daniele Tosi - ...
Needle/trocar

Radiofrequency ablation needle
Daniele Tosi - Optical fiber sensors for medical applications - Research acti...
Needle/trocar
(1) Insert FO probe/bundle, retracted
(2) Expand/block into position

(optional: cut needle arms
to desired ...
Cardiovascular
Top-notch
Performance
Miniature size
Distribution and
Integration
Immunity

➡ Excellent sensitivity to pres...
Cardiovascular
➡ Blood pressure monitoring
‣Localized: allows localizing the phenomena without
damping, spatial averaging,...
Fractional Flow Reserve

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University ...
Fractional Flow Reserve
2x optical fiber pressure
sensors allow direct
detection of FFR, preand post-sthenosis

Problems i...
Intra-aortic balloon (IAB)

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at Universi...
Fiber-optic IAB
Pressure detection
FO selling points:
- better stability to
patients movements
- better reproduction
of pu...
Setup phantom
Heart simulator

Spectrometer
ASE source

EFP
I sp
ectr

Heart pumping
Fiber inlet

Pres
sure

um

mea
s.

S...
Cardio phantom

Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limeri...
Stability (1 hr)
65

EFPI
Fluidic

0.63 mmHg

Pressure (mmHg)

64.5
64
63.5
63

2.76 mmHg

62.5
0

10

20

30

40

50

60
...
Ventricular assist
Demonstration at Cleveland Clinic, Mar 2013

FPI positioning
Ventricular assist

Reference (fluidic)

Pr...
Ventricular assist
Demonstration at Cleveland Clinic, Mar 2013

Daniele Tosi - Optical fiber sensors for medical applicatio...
Urodynamic
Top-notch
Performance
Miniature size
Distribution and
Integration
Immunity

➡
➡
➡
➡
➡
➡
➡
➡
➡

Miniature size (...
Urodynamic
“Standard” invasive urodynamics:
Mid-term (20-40 minutes) monitoring of the detrusor
muscle pressure and flowmet...
Urodynamic
Diagnostic based
on nomogram:
detrusor
pressure vs
uroflowmetry
➡ Direct
detection of
bladder outlet
obstruction...
In-vivo measurement
Feasibility test with Federico II University, Naples.

Infusion (375ml)

Urination

EFPI

Pico2000

Da...
In-vivo measurement
Feasibility test with Federico II University, Naples.

Daniele Tosi - Optical fiber sensors for medical...
In-vivo measurement
Feasibility test with Federico II University, Naples.

Urination
Cough

Stimulus

Daniele Tosi - Optic...
Direct BOO (proposal)

Differential pressure measurement
Bladder outlet obstruction (BOO) diagnostic

Interrogator

Daniel...
RF ablation of tumors
Top-notch
Performance
Miniature size
Distribution and
Integration
Immunity

➡
➡
➡ Cross-sensitivity ...
RFA description
Radiofrequency thermal ablation (RFA):
Achieving the complete ablation of a cancerous tumor by
burning the...
RFA in liver
Liver tissue sets a specific problem: ebullience releases the
watery part of cells, which conduct more than li...
Heat distribution
IR thermal camera - imaging

Is the model confirmed by localized sensors?
Is it possible to increase RFA ...
Heat distribution
IR thermal camera - imaging

Is the model confirmed by localized sensors?
Is it possible to increase RFA ...
Ex-vivo - setup
Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano

Daniele Tosi - Optical ...
Ex-vivo experiments
Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano

8mm

Daniele Tosi -...
Ex-vivo experiments
Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano

5mm

Daniele Tosi -...
Ex-vivo experiments
Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano

1mm

Daniele Tosi -...
Preliminary conclusions
The preliminary results obtained with EFPI/FBG do not
match the physical model, nor the thermal ca...
Robotic surgery
Top-notch
Performance
Miniature size
Distribution and
Integration
Immunity

➡ Excellent sensitivity to pre...
Robotic surgery
•Integration of miniature FO sensors in surgical tool
•Measurement of force: 3D lateral + axial, return ha...
Tool shafts

X. Liu, I. Iordachita, X. He, R. T. Taylor, J. U. Kang, “Miniature fiberoptic force sensor based on low-cohere...
Robotic surgery sensors
•Two alternative technologies: EFPI, FBG
•FBG in a spring configuration, to translate force to stra...
Conclusions
➡ Optical fiber sensors are well on their way to address
medical opportunities, usually in multiB markets
➡ Res...
Acknowledgments
‣ Federico II University - Urologic Clinic
‣ Universita’ di Pavia, Politecnico di Milano
‣ Cleveland Clini...
Thank you - Xie xie

➡ Cooperation
➡ Partnerships
➡ Funding proposals
... are welcome...
Daniele Tosi - Optical fiber senso...
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Daniele Tosi - OFSRC presentation at Jiliang University

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Presentation of fiber-optic sensors for medical devices, at Jiliang University, Dec 2013.

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Daniele Tosi - OFSRC presentation at Jiliang University

  1. 1. Optical fiber sensors for medical applications Research activities at University of Limerick [Jiliang University, 10 Dec 2013] Daniele Tosi daniele.tosi@ul.ie dan82ddt www.ofsrc.ul.ie
  2. 2. About University of Limerick Optical Fibre Sensors Research Centre [Marie Curie Fellow @ OFSRC] Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  3. 3. Partnerships Cleveland Clinic EFPI cardiovascular/demo Johns Hopkins Robotic surgery UL, OFSRC Pointec (licensing) Harbin Inst. Technol. Cyprus IT (EFPI partner) Staff exchange partnership Partners Italy Politecnico di Torino (FBG) Federico II Napoli (urodynamic) Universita’ di Pavia (RFA) Politecnico di Milano (RFA) LunaTEC Shenzhen Custom catheters supplier Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  4. 4. Outline ➡ Optical fiber sensors: properties and technology ‣EFPI - pressure, temperature, refractive index ‣Fiber Bragg grating (FBG), DTG, LPG ‣Sensor integration and interrogation ‣Catheterization ➡ Emerging applications in medical/biomedical ‣Cardiovascular, FFR, IABP ‣Urodynamics ‣Monitoring of radiofrequency thermal ablation ‣Robotic surgery tools ➡ Conclusions Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  5. 5. OFS properties Top-notch Performance Miniature size Distribution and Integration Immunity ➡ Excellent sensitivity to press., temp., strain ➡ <1με, 0.01˚C, <10Pa resolution ➡ Cross-sensitivity abating/compensation ➡ Miniature size (∅125μm, ∅40μm custom) ➡ Lightweight, non-invasive, embeddable ➡ Versatile fiber coating and catheterization ➡ Punctual sensors ➡ Multiplexed, switched, quasi-distributed ➡ Integration (lab in a fiber) ➡ Immune to EMI, radiation, MRI ➡ Fire-safe, passive device ➡ No interference with existing equipment Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  6. 6. EFPI EFPI: Fiber-optic Fabry-Perot interferometric sensor based on all-silica glass structure: (1) launch fiber, (2) diaphragm, (3) capillary Capillary (optional FBG) AIR-GAP Launch SM fiber Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick Diaphragm MM fiber
  7. 7. UL EFPI (pre-etch) Air-gap length L FP Spectrum ~ S0 + k cos[4πL/λ] L = 20.6μm Single-mode fiber phragm Dia ir-gap A L d Capillary Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  8. 8. UL EFPI (pre-etch) Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  9. 9. UL EFPI (pre-etch) Air-gap length L = L0 - Sp ΔP FP Spectrum ~ S0 + k cos[4π(L - Sp ΔP)/λ] Temperature: L = L0 - Sp ΔP + ST ΔT FBG L0 - Sp ΔP Pressure Sp = 1.60 nm/kPa L Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  10. 10. Commercial EFPI EFPI head: 200µm Encapsulation: 500µm Input fiber: 125µm Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  11. 11. Commercial EFPI Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  12. 12. Pressure detection RMSE = 2.29 mmH2O RMSE = 1.30 mmH2O Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  13. 13. Pressure detection RMSE = 2.29 mmH2O RMSE = 2.29 mmH2O = = 0.21 mmHg RMSE = 1.30 mmH2O Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  14. 14. Improved detection D. Tosi, S. Poeggel. G. Leen, E. Lewis, “Adaptive filter-based interrogation of high-sensitivity fiber optic Fabry-Perot interferometry sensors,” Sensors and Actuators A: Physical, in press Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  15. 15. Fiber Bragg grating (FBG) FBG = fiber optic filter FBG cascade ⬌ Multiplexing Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  16. 16. Fiber Bragg grating (FBG) •Information encoded in FBG optical spectrum •Linear dependance on strain and temperature •Top performance sensor •Easy interrogation Reflected Bragg wavelength shifts linearly with variation of tensile strain and temperature Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  17. 17. Fiber Bragg grating (FBG) Strain + temperature encoded in the sensing element Strain: can be converted into force, by package Temperature: for sensing, and compensation Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  18. 18. Draw-tower grating IOS hypertermia sensor: 5 FBG in 3 cm Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  19. 19. Long period grating (LPG) Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  20. 20. EFPI/FBG Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  21. 21. EFPI/FBG Δλ(ΔT, ΔP) ΔL(ΔT,ΔP) Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  22. 22. Cross-sensitivity Detuning: 0.03 kPa/°C -96% glass -99.6% mould Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  23. 23. White light setup Courtesy of Politecnico di Torino . . . . . . ... ... ... Switch SLED FBGA Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick . . .
  24. 24. White light setup Courtesy of Politecnico di Torino . . . FBGA . . . FBG matrix ... ... . . . ... SLED Switch SLED FBGA Switch Circulator Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  25. 25. Coherent light setup Courtesy of Politecnico di Torino . . . . . . FBG matrix ... ... . . . ... Switch Laser controller Photodiode Laser array Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  26. 26. Circulator Coherent light Switch setup Courtesy of Politecnico di Torino . . . Laser FBG matrix ... ... TEC . Photodiode . . . . . ... Switch Laser controller Photodiode Laser array Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  27. 27. Interrogation White light Coherent light Encoding Wavelength Amplitude Resolution 1 pm (150 pm) << 1 pm Throughput 1-100 Hz total >kHz/channel Switching 1/N * W 1/(N*W) # Sensors 2-50/channel <10 Cost (box) $12k $2.5k Stability Excellent Low Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  28. 28. Further integration ➡ Lab in a fiber ‣Integration of several sensing units in a single fiber ‣FBG (array), LPG, EFPI + bio/chemical (SPR) ➡ Quasi-distributed ‣Dense monitoring of parameters, localized ‣Bundle of EFPI, array of FBG, combination EFPI/FPI ➡ Cross-compensation ‣Sensing parameter + temperature + ref. index ‣Compensation matrix, detuning Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  29. 29. Pigtail catheter Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  30. 30. Pigtail catheter Contrast liquid 4F 2x probes (distal) French(F) = 1/3mm Excess bending Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  31. 31. Foley catheter Urology catheter, bi-sex Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  32. 32. Foley catheter Seal: epoxy or medical tape 1cm FO Infusion + uroflowmetry 4F Side holes allow infusion Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  33. 33. Needle/trocar Radiofrequency ablation needle Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  34. 34. Needle/trocar (1) Insert FO probe/bundle, retracted (2) Expand/block into position (optional: cut needle arms to desired length) (3) Push and project fibers Trocar provides blockage Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  35. 35. Cardiovascular Top-notch Performance Miniature size Distribution and Integration Immunity ➡ Excellent sensitivity to press., temp., strain ➡ ➡ ➡ ➡ ➡ ➡ ➡ ➡ Miniature size (∅125μm, ∅40μm custom) Lightweight, non-invasive, embeddable Versatile fiber coating and catheterization Punctual sensors Multiplexed, switched, quasi-distributed ➡ Immune to EMI, radiation, MRI ➡ ➡ No interference with existing equipment Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  36. 36. Cardiovascular ➡ Blood pressure monitoring ‣Localized: allows localizing the phenomena without damping, spatial averaging, fluid transfer (walls) ‣Multi-sensor: 2x sensors for obstructions (FFR) ‣Requires high speed: 100 Hz hardware to detect pulse ‣Used in the study of vasodilators/vasoconstrictors, localize the pressure effect (pilot project) Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  37. 37. Fractional Flow Reserve Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  38. 38. Fractional Flow Reserve 2x optical fiber pressure sensors allow direct detection of FFR, preand post-sthenosis Problems in long-term: - Drift: >5 mmHg/hr - Temperature compensation - Amplitude drifts Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  39. 39. Intra-aortic balloon (IAB) Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  40. 40. Fiber-optic IAB Pressure detection FO selling points: - better stability to patients movements - better reproduction of pulse peak Fiber-optic cable Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  41. 41. Setup phantom Heart simulator Spectrometer ASE source EFP I sp ectr Heart pumping Fiber inlet Pres sure um mea s. Sensor positioning (short access) Interrogator/processing Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  42. 42. Cardio phantom Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  43. 43. Stability (1 hr) 65 EFPI Fluidic 0.63 mmHg Pressure (mmHg) 64.5 64 63.5 63 2.76 mmHg 62.5 0 10 20 30 40 50 60 Time (min) Typical FO drift ~ 5 mmHg/hr. St. Jude drift: 4mmHg/10min Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  44. 44. Ventricular assist Demonstration at Cleveland Clinic, Mar 2013 FPI positioning Ventricular assist Reference (fluidic) Pressure readout Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  45. 45. Ventricular assist Demonstration at Cleveland Clinic, Mar 2013 Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  46. 46. Urodynamic Top-notch Performance Miniature size Distribution and Integration Immunity ➡ ➡ ➡ ➡ ➡ ➡ ➡ ➡ ➡ Miniature size (∅125μm, ∅40μm custom) Lightweight, non-invasive, embeddable Versatile fiber coating and catheterization Punctual sensors Multiplexed, switched, quasi-distributed ➡ ➡ ➡ No interference with existing equipment Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  47. 47. Urodynamic “Standard” invasive urodynamics: Mid-term (20-40 minutes) monitoring of the detrusor muscle pressure and flowmetry during a urology analysis that consists of infusion and voiding of the bladder Why fiber-optic: - FO sensors have a better responsivity and lower damping than air-charged catheter - It is possible to fit multiple fibers in the bladder: change the way bladder obstructions are diagnosed Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  48. 48. Urodynamic Diagnostic based on nomogram: detrusor pressure vs uroflowmetry ➡ Direct detection of bladder outlet obstruction (BOO) Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  49. 49. In-vivo measurement Feasibility test with Federico II University, Naples. Infusion (375ml) Urination EFPI Pico2000 Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  50. 50. In-vivo measurement Feasibility test with Federico II University, Naples. Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  51. 51. In-vivo measurement Feasibility test with Federico II University, Naples. Urination Cough Stimulus Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  52. 52. Direct BOO (proposal) Differential pressure measurement Bladder outlet obstruction (BOO) diagnostic Interrogator Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  53. 53. RF ablation of tumors Top-notch Performance Miniature size Distribution and Integration Immunity ➡ ➡ ➡ Cross-sensitivity abating/compensation ➡ ➡ ➡ ➡ ➡ ➡ Miniature size (∅125μm, ∅40μm custom) Lightweight, non-invasive, embeddable Versatile fiber coating and catheterization Multiplexed, switched, quasi-distributed Integration (lab in a fiber) ➡ Immune to EMI, radiation, MRI ➡ Fire-safe, passive device ➡ No interference with existing equipment Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  54. 54. RFA description Radiofrequency thermal ablation (RFA): Achieving the complete ablation of a cancerous tumor by burning the tumor + surrounding by means of Joule effect. In RFA the heat field is generated through 5-50W RF Needle, 1mm diameter Ablation, ~15min/cm Tumor, up to 5cm size RF field Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  55. 55. RFA in liver Liver tissue sets a specific problem: ebullience releases the watery part of cells, which conduct more than liver - the RF circuit is disconnected after 2-9 minutes ➡ Not possible for RFA to remove mid/large tumors, over 2 cm in diameter ➡ RFA is performed at ~60˚C rather than >100˚C. Cells mortality not guaranteed ➡ Need to resort to microwave ablation (MWA) ➡ Biocompatible gels can isolate needle from ebullient cells Numbers: 764k deceases (#3) Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  56. 56. Heat distribution IR thermal camera - imaging Is the model confirmed by localized sensors? Is it possible to increase RFA efficiency/duration? Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  57. 57. Heat distribution IR thermal camera - imaging Is the model confirmed by localized sensors? Is it possible to increase RFA efficiency/duration? Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  58. 58. Ex-vivo - setup Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  59. 59. Ex-vivo experiments Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano 8mm Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  60. 60. Ex-vivo experiments Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano 5mm Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  61. 61. Ex-vivo experiments Experiments with Universita’ di Pavia, San Matteo Hospital, Politecnico di Milano 1mm Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  62. 62. Preliminary conclusions The preliminary results obtained with EFPI/FBG do not match the physical model, nor the thermal camera imaging. We observe during ablation a higher temperature, and higher pressure than expected (105˚C and 80 kPa). Denser monitoring is needed to have a full reproduction of the physical phenomena. Is it possible to increase the RFA efficiency, by online monitoring of pressure/temperature field? Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  63. 63. Robotic surgery Top-notch Performance Miniature size Distribution and Integration Immunity ➡ Excellent sensitivity to press., temp., strain ➡ <1με, 0.01˚C, <10Pa resolution ➡ Cross-sensitivity abating/compensation ➡ Miniature size (∅125μm, ∅40μm custom) ➡ ➡ ➡ ➡ Multiplexed, switched, quasi-distributed ➡ Integration (lab in a fiber) ➡ Immune to EMI, radiation, MRI ➡ ➡ Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  64. 64. Robotic surgery •Integration of miniature FO sensors in surgical tool •Measurement of force: 3D lateral + axial, return haptic •Microsurgery (vitreoretinal surgery). •Size matter! <125μm attractive, 40μm fibers for animal... Da Vinci surgical tool: insufficient resolution to address microsurgery procedures. Need for a surgical tool that embeds sensors with <mN force detection + temperature compensation, to return a haptic feedback to the doctor. Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  65. 65. Tool shafts X. Liu, I. Iordachita, X. He, R. T. Taylor, J. U. Kang, “Miniature fiberoptic force sensor based on low-coherence Fabry-Perot interferometry for vitreoretinal microsurgery,” Biomedical Optics Express, v. 3, n. 5, 2012 Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  66. 66. Robotic surgery sensors •Two alternative technologies: EFPI, FBG •FBG in a spring configuration, to translate force to strain •Low sensitivity: 10 mN ⇢ 1 pm (1με) •It needs temperature compensation •EFPI promising, but larger size •Transfer of axial forces through the capillary •Proposal: all-EFPI configuration, axial+lateral+temperature Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  67. 67. Conclusions ➡ Optical fiber sensors are well on their way to address medical opportunities, usually in multiB markets ➡ Research emphasis on multi-sensing structures: lab-in-afiber, quasi-distributed, dense monitoring ➡ Scalability is a key factor for transitioning from lab to market, but compatibly with disposable cost ➡ Emerging applications raise the bar for sensing complexity: size, integration, mechanical prop., catheters ➡ Biocompatibility is a key issue: prevalence of all-glass structures, most packages not FDA-compliant! Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  68. 68. Acknowledgments ‣ Federico II University - Urologic Clinic ‣ Universita’ di Pavia, Politecnico di Milano ‣ Cleveland Clinic ‣ FP7 Marie Curie (299985-PROBESENSE) ‣ Science Foundation Ireland (RFP/ECE2898) ‣ Enterprise Ireland (IP-2012-0166-Y) ‣ University of Limerick, MSSI and CES depts. Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
  69. 69. Thank you - Xie xie ➡ Cooperation ➡ Partnerships ➡ Funding proposals ... are welcome... Daniele Tosi - Optical fiber sensors for medical applications - Research activities at University of Limerick
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