Digital diaphanoscopy method has potential to separate normal and pathological conditions of the maxillary sinuses. The entirety of all the features of the investigated area (the presence or absence of pathology, its etiology and morphological features) affects the resulting images of the maxillary sinuses by the digital diaphanoscopy. In this work, the MonteCarlo numerical simulation method was used to determine the patterns of propagation of light radiation in biological tissue. A biologically heterogeneous environment, represented by structures of the skull and maxillary sinuses, as well as pathological changes in them was modelled in the TracePro software.
The digital diaphanoscopy method seems promising for solving one of the urgent problems of modern otolaryngology, which is associated with providing accurate, painless and timely diagnosis of pathologies of the maxillary sinuses. Optical properties of the study area and their changes for different anatomical and gender features and pathologies presence determine the results of digital diaphanoscopy. Adjusting the parameters of the probing and measuring parts of digital diaphanoscopy devices taking into account these factors is important task to obtain similar light scattering patterns for different patients and the possibility of their subsequent comparison.
This paper presents the improved numerical model of the maxillary sinuses. The developed model considered the maxillary sinuses sizes, their location and asymmetry, various thicknesses of bone and soft tissues, size and localization of pathology (cystic fluid and tumor). The cross-sectional face model was more detailed and considered the curvature of the face. Simulation was carried out at various positioning of radiation source relative to the study area and detector. Additionally, the various rotation angles of the study area with radiation source relative to the detector were considered. The attenuation of probe radiation intensity at the detector was estimated using the Monte Carlo method in the TracePro (Lambda Software) for visible and near-IR wavelengths at the different intensity values.
The correlations between model signal and anatomical features of the study area, and the changes of the study area position were identified. It was established that registration of light scattering patterns at different position is important parameter for more accurate evaluation of the maxillary sinuses state and the localization of pathologies. The threshold values of the probe radiation intensity and the optimal study positions, which provide the optimal signal-to-noise ratio of the detectable signals, were identify.
Diagnosis of inflammatory diseases of the paranasal sinuses is one of the urgent problems of modern otolaryngology. Presently, radiography, computed tomography, magnetic resonance imaging, rhinoscopy and ultrasound are used to identify these pathologies. However, due to use of carcinogenic roentgen radiation during the study, a high level of falsenegative results and painfulness of the diagnostic procedures, application of these methods is limited. To overcome these shortcomings, the application of the digital diaphanoscopy method seems to be promising. For realization of this approach the experimental setup was designed and assembled. Low-intensity radiation of the visible and near IR ranges and CMOS-camera were used for translucence of the paranasal sinuses and visualizing the pattern of scattering light. To identify the range of exposure values of the CMOS-camera to obtain maximum sensitivity to identify of pathological changes, experimental studies were conducted on healthy volunteers and patients with inflammatory diseases of paranasal sinuses. During the studies the exposure time of CMOS-camera changed in the range from 0 to 39.7 ms with a step of 1 ms, followed by comparison of the results of digital diaphanoscopy with results of MRI. The results of study 20 volunteers and 15 patients of different genders and ages showed variations in the scattering patterns with the same exposure time. This was explained by such anatomic features as the structure of the skin, the thickness of the skull bone tissue, the size of the sinuses and their asymmetry.