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The extent of surgical resection is an important prognostic factor in the treatment of patients with glioblastoma. Optical coherence tomography (OCT) imaging is one of the adjunctive methods available to achieve the maximal surgical resection. In this study, the tumor margins were visualized with the OCT image obtained from a murine glioma model. A commercialized human glioblastoma cell line (U-87) was employed to develop the orthotopic murine glioma model. A swept-source OCT (SS-OCT) system of 1300 nm was used for three-dimensional imaging. Based on the OCT intensity signal, which was obtained via accumulation of each A-scan data, an en-face optical attenuation coefficient (OAC) map was drawn. Due to the limited working distance of the focused beam, OAC values decrease with depth, and using the OAC difference in the superficial area was chosen to outline the tumor boundary, presenting a challenge in analyzing the tumor margin along the depth direction. To overcome this and enable three-dimensional tumor margin detection, we converted the en-face OAC map into an en-face difference map with x- and y-directions and computed the normalized absolute difference (NAD) at each depth to construct a volumetric NAD map, which was compared with the corresponding H&E-stained image. The proposed method successfully revealed the tumor margin along the peripheral boundaries as well as the margin depth. We believe this method can serve as a useful adjunct in glioma surgery, with further studies necessary for real-world practical applications. [ABSTRACT FROM AUTHOR]

Herein, the performance of single-fiber reflectance spectroscopy (SFRS) in detection of cervical pre-cancerous squamous intraepithelial lesions (SIL) was compared with colposcopy. Based on the previous results obtained from 167 samples and finding the contributing parameters in differentiating SILs from non-SILs, a user-friendly interface was developed to detect the SILs using SFRS system. Detection of SILs in 301 patients was performed by both SFRS system and routine colposcopy. In addition to physician-determined sites, four quarters of the cervix were measured by SFRS system and suspicious lesions detected by either method were biopsied. Histopathologic results of the biopsied species were compared to the physician judgments based on colposcopy and the results of SFRS system. SFRS could differentiate between SILs and non-SILs with mean sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 38.3, 60.9, 15.2, and 84.3%, respectively. These values were obtained as 88.3, 10.6, 15.4, and 83.1% for the colposcopy, respectively. Although sensitivity of SFRS in detection of SILs is about twofold less than the colposcopy, it can reduce the number of unnecessary biopsies by a factor of more than 5.5. Therefore, the aid of SFRS system to the physician can reduce the number of unnecessary biopsies. On the other hand, both colposcopy and SFRS methods equally suffer from low detection worth in terms of positive/negative predictive values. In conclusion, using the online, simple and non-invasive SFRS system to choose between several suspicious sites in a patient in the clinic may be recommended. [ABSTRACT FROM AUTHOR]

This work presents the application of terahertz imaging to three-dimensional formalin-fixed, paraffin-embedded human breast cancer tumors. The results demonstrate the capability of terahertz for in-depth scanning to produce cross section images without the need to slice the tumor. Samples of tumors excised from women diagnosed with infiltrating ductal carcinoma and lobular carcinoma are investigated using a pulsed terahertz time domain imaging system. A time of flight estimation is used to obtain vertical and horizontal cross section images of tumor tissues embedded in paraffin block. Strong agreement is shown comparing the terahertz images obtained by electronically scanning the tumor in-depth in comparison with histopathology images. The detection of cancer tissue inside the block is found to be accurate to depths over 1 mm. Image processing techniques are applied to provide improved contrast and automation of the obtained terahertz images. In particular, unsharp masking and edge detection methods are found to be most effective for three-dimensional block imaging. [ABSTRACT FROM AUTHOR]

Purpose: Early and effective detection of cancers of the gastrointestinal tract will require novel molecular probes and advances in instrumentation that can reveal functional changes in dysplastic and malignant tissues. Here, we describe adaptation of a wide-field clinical fiberscope to perform wide-field fluorescence imaging while preserving its white-light capability for the purpose of providing wide-field fluorescence imaging capability to point-of-care microscopes.Procedures: We developed and used a fluorescent fiberscope to detect signals from a quenched probe, BMV109, that becomes fluorescent when cleaved by, and covalently bound to, active cathepsin proteases. Cathepsins are expressed in inflammation- and tumor-associated macrophages as well as directly from tumor cells and are a promising target for cancer imaging. The fiberscope has a 1-mm outer diameter enabling validation via endoscopic exams in mice, and therefore we evaluated topically applied BMV109 for the ability to detect colon polyps in an azoxymethane-induced colon tumor model in mice.Results: This wide-field endoscopic imaging device revealed consistent and clear fluorescence signals from BMV109 that specifically localized to the polypoid regions as opposed to the normal adjacent colon tissue (p < 0.004) in the murine colon carcinoma model.Conclusions: The sensitivity of detection of BMV109 with the fluorescence fiberscope suggested utility of these tools for early detection at hard-to-reach sites. The fiberscope was designed to be used in conjunction with miniature, endoscope-compatible fluorescence microscopes for dual wide-field and microscopic cancer detection. [ABSTRACT FROM AUTHOR]

Blood vessel plaque with a large lipid core is at risk of becoming thrombus and is likely to induce acute heart disease. To prevent this, it is necessary to determine not only the plaque's size but also its chemical composition. We, therefore, made the prototype of a combination probe to diagnose carotid artery plaque. It is used to differentiate propagation characteristics between light spectra and ultrasonic images. By propagating light and ultrasound along a common direction, it is possible to effectively warm the diagnosis domain. Moreover, the probe is thought to be compact and be easy to use for diagnosing human carotid artery plaque. We applied the combination probe to a carotid artery phantom with a lipid area and obtained an image of the ultrasonic velocity change in the fatty area. [ABSTRACT FROM AUTHOR]

A Monte Carlo model of steady-state light transport in multi-layered tissues had been compiled in C language so that it could be applied on various computers easily. In the standard model of photon transport in a semi-infinite geometry, only a group of optical parameters are employed (the absorption coefficient, the scattering coefficient and the anisotropy factor). In order to properly simulate the multi-component media, we proposed a modified model in which we gave each component a weight based on its percentage composition in every layer of tissue or complex solution, while the MCML model [Monte Carlo model of light transport in multi-layered tissues by Wang et al. (Comput Meth Prog Biol 47:131-146, )] cannot directly simulate the photon migration in multi-component media. The computational results using the modified model have been validated by existing analytical methods and the experiment. We have adopted the partial least-squares regression to measure the inner component's percentage of the model solution of biological tissue, the percentage errors of both the calibration and prediction were $$>$$ 1 %. It has been proven that the modified model is able to effectively simulate the multi-component media. It also has a potential advantage to be a valid method for relevant applications in biomedical optics. [ABSTRACT FROM AUTHOR]

Lasers used in dermatological treatments are presented. Commercially available semiconductor lasers (laser diodes) are also presented for comparison. Potential applications of semiconductor lasers to optical information processing as applied to the human body or noninvasive diagnosis as well as medical treatment are discussed. In addition, the current application of LEDs to dermatology is also included in the paper. [ABSTRACT FROM AUTHOR]

A new concept and its methodology for studying human meridians are presented based on rigorous and scientific observation on the objective existence of human meridians in view of biomedical optics. According to this methodology, the infrared radiant characteristics of acupuncture meridians over human body and the optical transport properties of light propagating along the meridian are reported. This study, thus, confirms the existence of acupuncture meridians, sheds new light on an approach to investigation of human meridians and offers a new perspective in understanding the potential meridian functions such as energy and information transfer and physiological regulation. [ABSTRACT FROM AUTHOR]

The article discusses the study regarding the measurement of optical signals in the cortical tissue via multi-spectral imaging system to examine the impact of skull cranial window to haemoglobin concentration. It explores the comparison of the cortical tissue of the experimented guinea pigs and exposed cortex to measure the concentration change in haemoglobin as influenced by the scattering and absorption properties of the skull. It notes the concentration changes derived from optical signals.

Near infrared spectroscopy (NIRS) is used to measure the change in blood volume and oxygenation in the brain cortex induced by functional brain activation. The development of an adequate model to calculate light propagation in the head is very important because the light is strongly scattered in the tissue and this causes ambiguity in the volume of tissue interrogated with a source-detector pair of the NIRS instrument. In this study, a two-dimensional realistic head model is generated from a MRI scan of a human adult head. The light propagation in the head model is calculated by the hybrid Monte Carlo-diffusion method to obtain the change in detected intensity caused by a focal absorption change in the grey matter or in the white matter to discuss the relationship between the depth of the activated region and the sensitivity of the NIRS signal. The sensitivity to the activated region in the white matter steeply decreases with an increase of the depth of the activated region because the spatial sensitivity profile is mainly confined to the grey matter. The contribution of the focal brain activity to the NIRS signal is determined by not only the depth of the activated region from the head surface but also the depth of the activated region from the brain surface. [ABSTRACT FROM AUTHOR]

The colour of tattooed skin has been predicted by a Monte Carlo method based on the optical coefficient spectra of the skin and tattoo dyes. Slices of pig skin, a tattoo phantom and skin phantoms with different thickness were prepared, and their reflectance and transmittance spectra were measured using an integrating sphere at wavelengths varying from 400nm to 700nm. The absorption and scattering coefficient spectra of skin phantoms, pig skins and the tattoo phantom were each calculated using the inverse Monte Carlo method. The skin phantoms and pig skins were overlaid on the tattoo phantom, and the reflectance spectra of the two-layered structures were measured. The reflectance spectra of the two-layered structures were calculated from the optical coefficient spectra using the Monte Carlo method. They agreed well with the measured spectra. The colour differences between the calculated and measured spectra were also evaluated by the L*a*b* colour space distances and showed good agreement, with 3.49 for the skin phantoms and 8.27 for the pig skins. [ABSTRACT FROM AUTHOR]