19 Bio-applications of NIR Spectroscopy
421
Recording of spectra and establishment of calibration and validation procedures was
carried out in the same manner as in the previous contribution published by the same
authors [9].
Interestingly, the problem of biological cells appearance in the sample was investigated as a factor potentially influencing the performance of NIR spectroscopy in
food analytical applications. For example, Tsenkova et al. examined the influence
of high somatic cell count (SCC) in non-homogenized cow milk on the accuracy of
NIR spectroscopic determination of fat, protein and lactose content [11]. Transmittance spectra of 258 milk samples were analyzed in SW-NIR, 14,285–9090 cm
−1
(700–1100 nm) region. The most accurate calibrations, evaluated through analyzing
the standard error of prediction and the correlation coefficient, were obtained for
the samples with low SCC. The accuracy decreased notably in the scenario, where
calibration models constructed on the basis of low SCC milk were used to predict
the content of the examined components in samples with high SCC, and vice versa.
Therefore, SCC factor is meaningful and highly influences the accuracy of fat, protein
and lactose determination. This dependence strongly affects robustness of analysis
and needs to be taken into consideration during the determination of milk chemical
composition by NIR spectroscopy.
19.4 Serum Analysis
Nioka et al. employed NIR spectroscopy in their approach to test breast tumorbearing patients who are undergoing a biopsy [12]. The aim was to see if angiogenesis
and hypoxia can be used as meaningful factors in detecting cancer. In that attempt,
continuous short-wave NIR (SW-NIR) spectroscopy was employed to measure blood
hemoglobin concentration and to obtain blood volume. This would allow answering
the question, whether the correlated parameters, the total hemoglobin content and
oxygen saturation, can serve as the biomarkers for the angiogenesis and hypoxia.
Through monitoring these two parameters, high total hemoglobin and hypoxia score,
the sensitivity and specificity of cancer detection could be achieved at 60.3% and
85.3% levels, respectively. It was concluded that smaller-size tumors prove to be
more challenging for detection by NIR spectroscopy, whereas ductal carcinoma
in situ (DCIS) can be detected using configuration assumed in the discussed study.
It was noted that in larger-size tumors, there is significantly higher deoxygenation in
invasive and ductal carcinoma in situ DCIS than in that of benign tumors [12].
Blood-oxygen-level-dependent contrast functional magnetic resonance
imaging (BOLD-fMRI) is a favored tool for detection of brain cancer. However,
this technique faces some limitations. The BOLD-fMRI diagnosis in brain disorders
such as stroke and brain had been shown in the previous studies to be prone
to yield incorrect image activation areas correctly in such cases. Sakatani et al.
performed an investigation upon the application of NIR spectroscopy for this
purpose [13]. To clarify the characteristics of the cerebral blood oxygenation (CBO)
changes occurring in stroke and brain tumors, the authors have been comparing
421
Recording of spectra and establishment of calibration and validation procedures was
carried out in the same manner as in the previous contribution published by the same
authors [9].
Interestingly, the problem of biological cells appearance in the sample was investigated as a factor potentially influencing the performance of NIR spectroscopy in
food analytical applications. For example, Tsenkova et al. examined the influence
of high somatic cell count (SCC) in non-homogenized cow milk on the accuracy of
NIR spectroscopic determination of fat, protein and lactose content [11]. Transmittance spectra of 258 milk samples were analyzed in SW-NIR, 14,285–9090 cm
−1
(700–1100 nm) region. The most accurate calibrations, evaluated through analyzing
the standard error of prediction and the correlation coefficient, were obtained for
the samples with low SCC. The accuracy decreased notably in the scenario, where
calibration models constructed on the basis of low SCC milk were used to predict
the content of the examined components in samples with high SCC, and vice versa.
Therefore, SCC factor is meaningful and highly influences the accuracy of fat, protein
and lactose determination. This dependence strongly affects robustness of analysis
and needs to be taken into consideration during the determination of milk chemical
composition by NIR spectroscopy.
19.4 Serum Analysis
Nioka et al. employed NIR spectroscopy in their approach to test breast tumorbearing patients who are undergoing a biopsy [12]. The aim was to see if angiogenesis
and hypoxia can be used as meaningful factors in detecting cancer. In that attempt,
continuous short-wave NIR (SW-NIR) spectroscopy was employed to measure blood
hemoglobin concentration and to obtain blood volume. This would allow answering
the question, whether the correlated parameters, the total hemoglobin content and
oxygen saturation, can serve as the biomarkers for the angiogenesis and hypoxia.
Through monitoring these two parameters, high total hemoglobin and hypoxia score,
the sensitivity and specificity of cancer detection could be achieved at 60.3% and
85.3% levels, respectively. It was concluded that smaller-size tumors prove to be
more challenging for detection by NIR spectroscopy, whereas ductal carcinoma
in situ (DCIS) can be detected using configuration assumed in the discussed study.
It was noted that in larger-size tumors, there is significantly higher deoxygenation in
invasive and ductal carcinoma in situ DCIS than in that of benign tumors [12].
Blood-oxygen-level-dependent contrast functional magnetic resonance
imaging (BOLD-fMRI) is a favored tool for detection of brain cancer. However,
this technique faces some limitations. The BOLD-fMRI diagnosis in brain disorders
such as stroke and brain had been shown in the previous studies to be prone
to yield incorrect image activation areas correctly in such cases. Sakatani et al.
performed an investigation upon the application of NIR spectroscopy for this
purpose [13]. To clarify the characteristics of the cerebral blood oxygenation (CBO)
changes occurring in stroke and brain tumors, the authors have been comparing