combined raman spectroscopy and autofluorescence method for tumors research
DESCRIPTION
The problem of noninvasive monitoring of human tissues cancer detection requires innovate diagnostic method with high precision. In current work, we used a combined Raman spectroscopy and autofluorescence imaging method which allowed to determine skin lesion type. Autofluorescence (AF) and Raman spectroscopy (RS) analysis of skin tissue increase the information content of pathology diagnostics. The combined diagnostic method helps to scan large tissue areas using AF analysis of the scanning tissue with subsequent RS examination of suspicious tissue areas. Combined approach saves time of tissue investigation and increases ultimate accuracy of the tumor type determination. Safety and speed, of the combined method show its high potential in dermatology and oncology. Raman spectroscopy allows to determine malignant changes in tissue. Specific peaks were revealed in Raman scattering shifts in tumors sensing with 785 nm laser, spectrograph resolution was 0.05 nm. Raman spectra researches of lesions allowed us to formulate the criteria for human tumors type determining. More than 50 human cancer tumors samples were researched by the combined method. We researched two-step phase method for skin cancer type diagnosis based on the localization changes in the spectral intensity of Raman bands in the 1300-1340, 1430-1460 and 1640-1680 cm-1. At the first step, we analysed spectral intensity changes of the Raman bands in 1300-1340 and 1640-1680 cm-1 in relation to the intensity of the 1450 cm-1 in a phase plane. The second step of the phase method we analysed absolute changes in the intensities of the 1320, 1450, 1660 cm-1 bands of healthy tissue and pathologies in the non-normalized Raman spectra. The Quadratic Discriminant Analysis was used for classification tumors type at the phase plane. Superior diagnostic efficiency of the combined method of tissue analysis achieved by implementation of the proposed RS phase method, which allows to identify human tumors type with a sensitivity and a specificity more than 85%. It is important to note that AF and RS analysis could be used as separate methods. It allows a medical staff to use advantages of specific method focusing on the individual patient.TRANSCRIPT
25 September 2014 Saratov, Russia
Combined Raman spectroscopy & autofluorescence method for tumors research
Dmitry Artemyeva, Valery Zakharova, Ivan Bratchenkoa,Oleg Myakinina, Sergey Kozlovb, Alexandr Moryatovb.
a - Samara State Aerospace University, b - Samara State Medical University
Saratov Fall Meeting Symposium: Optics & Biophotonics 2014
- Spectroscopy and Molecular Modeling XV -
© Laser and Biotechnical Systems Dept. of SSAU, 2014
96% 4% 80% 20%
Skin cancer mortality (US, 2007) *
New cases of skin cancer(US, 2007) *
Melanoma
Nonmelanoma skin cancers
Motivation
* - http://www.proteksol.com/index.php/en/skin-cancers.html
20%
Motivation
* - Chissov, V. I., et. al. “Malignant neoplasms in Russia in 2010 (morbidity and mortality),” Ministry of Health, P. 260 (2013).
Evolution of melanoma incidence rates per 100,000 population, by Sex, Russia, 2000-2010 *
* - Morton C. A., Mackie R. M. “Clinical accuracy of the diagnosis of cutaneous malignant melanoma,” Br J Dermatol., 138(2), 283-287, (1998).
20%
Motivation
Raman + AF spectroscopy fast scanning of large areas, high accuracy (>85%)
The diagnostic accuracy of malignant melanoma*:
80% - dermatologist with >10 years experience; 62% - registrar with 3-5 years experience;56% - registrar with 1-2 years experience.
Solution – using of instrumental methods
Optical coherence tomography
Ramanspectroscopy
Autofluorescencespectroscopy
Backscatteringspectroscopy
20%
Experimental setup
20%
Data processing
a – raw data;b – averaging;c – autofluorescence separating.
a b
c
20%
AF analysis
AF spectra: a - typical spectra of malignant melanoma (MM), basal cell carcinoma
(BCC), nevus, squamous cell carcinoma (SCC) and normal skin; b - typical spectra of malignant melanoma and normal skin built with
confidence intervals in the 790-920 nm range.
Sratio=Stumor/Sskin
sensitivity of 56% and specificity of 93% for melanoma diagnosis (Sratio = 1.2). 50 in vivo skin samples.
a b
20%
AF analysis
Illustration of autofluorescence study of malignant melanoma. a – AF tumor imaging, b – AF map of melanoma in normal skin.
a b
20%
Raman spectra of skin
Typical normalized Raman spectra in the 1200-1800 cm-1 range of skin samples.
I1320 I1660
20%
Raman data discrimination
PCA discrimination of skin tumors.
sensitivity – 66.7%specificity – 100%
20%
Raman data discrimination
LDA (a) and QDA (b) discrimination (melanoma vs. other skin tumors)
LDA: Sensitivity – 66.7% and Specificity – 88.6%QDA: Sensitivity – 77.8% and Specificity – 88.6%
a b
a b
I1320 I1320
I1660I1660
20%
Two-step RS method
Skin tumors in vivo classification by two-step Raman spectroscopy method; (a) – first step of RS method, (b) – second step of RS method.
Two-step RS method with QDA for melanoma diagnosis: sensitivity – 89% and specificity – 88%
x: I1320 / I1450
I1320 ΔI1320
ΔI1450I1660
x: |I1320(m) – I1320
(h)| / (I1320
(m) + I1320(h))
Results
Superior diagnostic efficiency of combined method achieved by implementation of the proposed RS phase method, allows to identify malignant melanoma with accuracy at least dermatologist with >10 years experience (88%).
1
2
3
AF and RS analysis of skin tissue increase the information content of pathology diagnostics;
The combined method helps to scan large tissue areas using AF analysis with subsequent RS examination of suspicious points;
Dmitry Artemyev
Researcher of Photonics Laboratory
443086 Russia, Samara, Lukacheva str., 39b, office 314
Email: [email protected]: + 7(846) 267-45-50