Infrared thermal imaging technology is another new branch for medical imaging after traditional medical imaging technologies such as X-ray, ultrasound and magnetic resonance (MRI). It has the advantages of noninvasive, nondestructive, simple and fast. Its application can radiate multiple clinical departments. This paper mainly expounds the principle, influencing factors of medical infrared thermography and its application in radiation protection and other medical fields.

The suspicion of mediastinal alterations, always includes in its initial study, the chest radiography. The identification of mediastinal alterations in the X-ray is a priority. The knowledge of the mediastinal references and the identification of their alterations allows the suspicion of a pathology specific to each of the mediastinal spaces. When the semiology of mediastinal lesions, their location and the three most frequent pathologies are taken into account, the possibility of having an etiological diagnosis increases^[1]. This is a review article based on a detailed literature search, in which radiological mediastinal references are studied, with emphasis on the epidemiological data of each one of them.

The micro staring hyperspectral imager can simultaneously acquire two spatial and one spectral images, and only record the external orientation elements of the entire hyperspectral image rather than the external orientation elements of each frame of the image, which avoids the geometric instability during scanning, effectively solves the problem of large geometric deformation of the small line scanning hyperspectral imager, and is suitable for the small UAV load platform with unstable attitude. At present, most of the research focuses on the radio-metric correction method of line scan hyperspectral imager. The application time of staring hyperspectral imager is short, and there is no mature data processing re-search at home and abroad, which hinders the application of UAV micro staring hyperspectral imaging system. In this paper, the calibration method of the linearity and variability of the radiation response of the micro staring hyperspectral imager on the UAV is studied, and the effectiveness of this method is quantitatively evaluated. The results show that the hyperspectral image has obvious vignetting effect and strip phenomenon before the correction of radiation response variability. After the correction, the radiation response variation coefficient of pixels in different bands decreases significantly, and the vignetting effect and image strip decrease significantly. In this paper, a multi-target radiometric calibration method is proposed, and the accuracy of radiometric calibration is verified by comparing the calibrated hyperspectral image spectrum with the measured ground object spectrum of the ground spectrometer. The results show that the calibration results of the multi-target radiometric calibration method show better results, especially for the near-infrared band, and the difference with the surface reflectance measured by the spectrometer is small.

Based on the characteristics of liquid lens sparse aperture imaging, a radiative multiplet array structure is proposed; a simplified model of sparse aperture imaging is given, and the analytical expression of the modulation transfer function is derived from the optical pupil function of the multiplet array structure; the specific distribution form of this multiplet array structure is given, and the structure parameters are approximated by the dimensionless method; the two types of radiative multiplet array structures are discussed, and the filling factor, redundancy, modulation transfer function and other characteristic parameters are calculated. The physical phenomena exhibited by the parametric scan are discussed, and the structural features and imaging characteristics of these two arrays are compared. The results show that the type-II structure with larger actual equivalent aperture and actual cutoff frequency and lower redundancy is selected when the average modulation transfer function and the IF characteristics of the modulation transfer function of the two structures are close to each other; the type-II structure has certain advantages in imaging; the conclusion is suitable for arbitrary enclosing circle size because the liquid lens-based multiplet array structure adopts dimensionless approximation parameters; compared with the composite toroidal structure, the radiative multiplet mirror structure has a larger actual cut-off frequency and actual equivalent aperture when the filling factor is the same.

To address the problem that the imaging inversion method based on a single model in integrated aperture imaging is difficult to effectively correct model errors and perform accurate image reconstruction, a dual-model (DM)-based integrated aperture imaging inversion method is proposed for correcting the parametric errors of the inversion model and performing highly accurate millimeter-wave image reconstruction of the target scene. In view of the different parameter sensitivities of the Fourier transform (MFFT) model and the G-matrix (GM) model, the proposed DM method first corrects the imaging parameters with errors accurately by comparing the reconstruction errors of the two models; then recon-structs a high-precision target image based on the accurate GM model with the help of an improved regularization method. It is proved by simulation experiments that the proposed DM method can effectively correct the parameter errors of the imaging model and reconstruct the target scene with high accuracy in millimeter wave images compared with the traditional single-model imaging method.

Objective: To evaluate the radiographic characteristics of dentigerous cysts (DC) diagnosed at the School of Stomatology of the Universidad Peruana Cayetano Heredia (UPCH) during the period of 2010–2017. Material and methods: Retrospective, descriptive, observational and cross-sectional study, where the panoramic radiographs of 37 cases of DC were selected. Results: The total number of diagnosed cases of dentigerous cysts was 233, which after inclusion and exclusion criteria, 37 cases were obtained, of which 45.9% of cysts were found in the second decade of life with a higher frequency of 51.4 percent for women, and a jaw predilection of 59.5% in all cases. In addition, it was found that 97.3% of the cases were radiolucent, defined limits were found in 67.6%, corticalized edges in 54.1% and unilocular in 94.6%. All dentigerous cysts were associated with a tooth, of which closed apex (48.6%) and tooth displacement (59.5%) were observed. The adjacent tooth was not affected in 56.8% of cases, but its hard lamina was affected (59.5%). The 68.2% of cases did not affect the basal mandibular cortex, but did displace the inferior dental canal (54.5%) and 46.7% of cases displaced the floor of the maxillary sinus. Conclusions: Most of the results obtained on the characteristics in the Peruvian population support previous studies reported in America, Europe and Asia. Radiographically the dentigerous cyst showed characteristics that support its clearly benign behavior.