![]() ![]() Microscopic tumor spread beyond the macroscopically visible tumor mass in bone increases spatial complexities at the bone tumor resection margins and may lead to the loss of local tumor control (Lubek and Magliocca 2017). In the future, direct electrolyte tracking using LIBS should be applied to other intraoperative challenges in surgical oncology to advance rapid bone analysis by spectroscopic–optical techniques.īone-infiltrating tumors with microscopic bone spread constitute a special cancer phenotype, in which minimal and macroscopically invisible changes in bone contrast with fatal survival effects (Singh et al. Conclusionĭepth profiling using LIBS might enable the detection of microscopic tumor spread in bone. LIBS-based depth profiles at the tumor border region can be used to track tumor-associated changes within the bone with shot accuracy based on the distribution of K. Increased potassium (K) emission values in otherwise typically healthy bone spectra are the first spectral signs of tumorous bone invasion. Solid calcium (Ca) from hydroxyapatite and soluble Ca from dissolved Ca can be reliably differentiated using LIBS and reflect the natural heterogeneity of healthy bone. For the histological validation of the lasered positions, the mandibular section was marked with a thin separating disc. Spectral and electrolytic depth profiles were analyzed across 30 laser shots per laser spot position in healthy bone and at the tumor border. MethodsĪfter en bloc resection, the tumor-infiltrated mandible section of a patient’s segmental mandibulectomy specimen was natively investigated using LIBS. The present study aimed to use LIBS-based depth profiling based on electrolyte disturbance tracking to evaluate the detection of microscopic tumor spread in bone. Laser-induced breakdown spectroscopy (LIBS) has recently been introduced as a promising option for rapid bone analysis. Practice problem 2.Microscopic tumor spread beyond the macroscopically visible tumor mass in bone represents a major risk in surgical oncology, where the spatial complexity of bony resection margins cannot be countered with rapid bone analysis techniques. Which spectrum in Figure IV.1.B (orange or blue) has greater sensitivity? Provide both qualitative and quantitative justification. Problems 4 and 5 target the relationship between the wavelength, frequency and energy of UV light often used in spectroscopic measurements. Problems 1 – 3 below request your analysis of these spectra’s sensitivity and resolution. Practice problems Figure IV.1.B Two spectra (two peaks in each) are shown. Thus the spectral width of the spectrum is 12.5 ppm (11.0 - (-1.5)). The X-axis covers a range of values form -1.5 ppm (on the right) to 11.0 ppm (on the left). The frequency (X-axis) of the spectrum is labeled in units of parts-per-million (ppm).An example of poor/insufficient resolution: most peaks within 1-2 ppm and 8-9 ppm are not resolved from the adjacent spectral lines.For these peaks, the recording provides an excellent resolution. Another example of a well-resolved peak is the line at 6 ppm. An example of well resolved peaks: two signals, one right below 10 ppm and one right above it are well-resolved.The sensitivity of this recording is overall strong as the noise level (wiggles of the baseline) is obviously lower than the intensity of most peaks and the signal-to-noise level is way greater than the value of 1.Thus, the spectrum has some value but its sensitivity and resolution need to be analyzed critically. General assessment: the spectrum allows reliable observation of some individual signals and shows some groups of signals which appear as collectives. ![]() Here are some comments on sensitivity and resolution with some peaks as study cases. Let’s take a quick look at the spectrum in Figure IV.1.A above. From this table we can see that for example infrared spectroscopy deals with radiation frequency values of 3.0×10 2 – 3.0×10 5 GHz (1 Hz = 1 oscillation per second 1 GHz = 10 9 Hz), energy values of 2.0×10 -29 – 2.7×10 -22 kJ and wavelength values of 700 nm – 1 mm.Įxamples (Quiz MC questions with a new Spectrum will be presented from the Examples here) Most common types of irradiation and corresponding ranges of frequency, wavelength and energy. Thus, in Table IV.1.I the frequency and energy values grow from left to right, whereas the wavelength values grow from right to left (and hence each wavelength range is bracketed from its largest to smallest values). From these formulas, we see that quantum’s frequency and energy values are inversely proportional to its wavelength. These relationships are parametrized via two universal constants, speed of light \(c\) and Plank’s constant \(h\).
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