C. Liu et al/ Journal of Luminescence 119-120(2006)132-136 133 already in the middle stage or even the later period 2. Samples and methods of cancer when they begin their therapy To enhance the early detection rate, much n our experiments, the pathological sections of research work has been done in the last years by human normal and diseased breast tissues in using spectroscopic methods [2,3], which are different cancerous stages (i.e. benign and malig mostly based on compact spectrometers focusing nant) are stuck to a CaF2 crystal for standard on UV excitation with the purpose to reach a FTIR analysis. All of the specimens are prepared relative high fluorescence yield. In addition, the in the Pathology Department of the Cancer laser spectroscopy provides a powerful and sensi- Hospital, Medical Center of Fudan University tive approach to reveal changes in the structural under the permission and authorization of the and biochemical properties that occur in health relevant rules in China and abnormal cells in tissues [4]. There are well- The IR spectra were measured by the bomen known intrinsic fluorophores, which are bound to DA-8 FTIR spectrometer with an energy resolu- proteins within cells and fluoresce in visible tion up to 0.004 cm at the ir beamline of ctral region, can display well-defined spectral National Synchrotron Radiation Laboratory features. But it is always difficult to obtain (NSRL), University of Science and Technology properly the quantitative differences in spectral of China. The IR absorption spectrum was characteristics among normal, precancerous and scanned in transmission mode. To eliminate the cancerous tissues from the spectra Georgakoudi et differences due to the nonuniformity of thickness al. [5] pointed out that one of the factors hindering of samples and the varying of intensity of light the extraction of quantitative biochemical infor- source, all spectra were su bsequently calibrated mation from measured tissue fluorescence spectra was the presence of potentially significant distor- tions introduced by tissue scattering and absorp- 3. Results and discussion tion. They have developed a method for extracting the fluorescence spectral features of collagen and The SR-FTIR spectra of normal, benign and NAD(P)H in vivo over a wide range of excitation and emission wavelengths [5]. In recent years, a from 900 to 3600 cm. The absorption peaks are new bio-spectroscopic technique, the Fourier concentrated mostly in three energy ranges. First transform infrared(FTIR) spectroscopy, has been in range of 900-1200 cm the IR absorption is applied to study on biology samples at high spatial mainly due to the cellular constituents of carbohy solutions [6]. This technique enables one to study drate, nucleic acids and the phosphates; then is the the state of chemical bonds and the relative absorption due to proteins in 1400-1750cm and concentrations of lipids, proteins, carbohydrates that in 2700-3600 cm should result from the and phosphorylated molecules, etc. On the other absorption of lipids and N-h amino groups [7I hand, the synchrotron radiation has unique The IR absorption spectra in 900-1200cm-I characteristics in infrared(IR) range compared range are shown in Fig. l(a) and their second ness,excellent collimation and broad continuous Fig. 1(b). As we know that the glycoge ed in with blackbody radiations, such as high bright order derivatives are calculated and displa spectrum. Therefore, it can produce IR spectra kind of important carbohydrates in breast tissue. with higher ratio of signal to noise and better It should make an important contribution to IR spatial resolution than conventional IR spectrum. absorption in this region. Curves I, II and Ill are In this paper, in order to obtain more information corresponding to the absorption due to normal and comprehension of the breast cancer, we have benign and malignant tissues, respectively studied the spectral characteristics of breast Through the second-order derivative of absorption tissues, which are normal or in different cancerous curves, we note that the absorption spectrum of ages by synchrotron radiation based FTIr normal tissue is of more abundant spe (SR-FTIR) spectroscopy features than one of benign tumor tissues, butalready in the middle stage or even the later period of cancer when they begin their therapy. To enhance the early detection rate, much research work has been done in the last years by using spectroscopic methods [2,3], which are mostly based on compact spectrometers focusing on UV excitation with the purpose to reach a relative high fluorescence yield. In addition, the laser spectroscopy provides a powerful and sensi￾tive approach to reveal changes in the structural and biochemical properties that occur in healthy and abnormal cells in tissues [4]. There are well￾known intrinsic fluorophores, which are bound to proteins within cells and fluoresce in visible spectral region, can display well-defined spectral features. But it is always difficult to obtain properly the quantitative differences in spectral characteristics among normal, precancerous and cancerous tissues from the spectra. Georgakoudi et al. [5] pointed out that one of the factors hindering the extraction of quantitative biochemical infor￾mation from measured tissue fluorescence spectra was the presence of potentially significant distor￾tions introduced by tissue scattering and absorp￾tion. They have developed a method for extracting the fluorescence spectral features of collagen and NAD(P)H in vivo over a wide range of excitation and emission wavelengths [5]. In recent years, a new bio-spectroscopic technique, the Fourier transform infrared (FTIR) spectroscopy, has been applied to study on biology samples at high spatial resolutions [6]. This technique enables one to study the state of chemical bonds and the relative concentrations of lipids, proteins, carbohydrates and phosphorylated molecules, etc. On the other hand, the synchrotron radiation has unique characteristics in infrared (IR) range compared with blackbody radiations, such as high bright￾ness, excellent collimation and broad continuous spectrum. Therefore, it can produce IR spectra with higher ratio of signal to noise and better spatial resolution than conventional IR spectrum. In this paper, in order to obtain more information and comprehension of the breast cancer, we have studied the spectral characteristics of breast tissues, which are normal or in different cancerous stages by synchrotron radiation based FTIR (SR–FTIR) spectroscopy. 2. Samples and methods In our experiments, the pathological sections of human normal and diseased breast tissues in different cancerous stages (i.e. benign and malig￾nant) are stuck to a CaF2 crystal for standard FTIR analysis. All of the specimens are prepared in the Pathology Department of the Cancer Hospital, Medical Center of Fudan University under the permission and authorization of the relevant rules in China. The IR spectra were measured by the BomenTM DA-8 FTIR spectrometer with an energy resolu￾tion up to 0.004 cm
1 at the IR beamline of National Synchrotron Radiation Laboratory (NSRL), University of Science and Technology of China. The IR absorption spectrum was scanned in transmission mode. To eliminate the differences due to the nonuniformity of thickness of samples and the varying of intensity of light source, all spectra were subsequently calibrated. 3. Results and discussion The SR–FTIR spectra of normal, benign and malignant breast tissues have been investigated from 900 to 3600 cm
1 . The absorption peaks are concentrated mostly in three energy ranges. First, in range of 900–1200 cm
1 the IR absorption is mainly due to the cellular constituents of carbohy￾drate, nucleic acids and the phosphates; then is the absorption due to proteins in 1400–1750 cm
1 ; and that in 2700–3600 cm
1 should result from the absorption of lipids and N–H amino groups [7]. The IR absorption spectra in 900–1200 cm
1 range are shown in Fig. 1(a) and their second order derivatives are calculated and displayed in Fig. 1(b). As we know that the glycogen is one kind of important carbohydrates in breast tissue. It should make an important contribution to IR absorption in this region. Curves I, II and III are corresponding to the absorption due to normal, benign and malignant tissues, respectively. Through the second-order derivative of absorption curves, we note that the absorption spectrum of normal tissue is of more abundant spectral features than one of benign tumor tissues, but ARTICLE IN PRESS C. Liu et al. / Journal of Luminescence 119– 120 (2006) 132–136 133