Journal of Medical Signals and Sensors
Volume:8 Issue: 3, Jul-Sep 2018

People with diabetes need to monitor their blood sugar levels constantly and attend health centers regularly for checkups. The aim of this study is to provide a healthcare system for mobile blood glucose and bilirubin monitoring.
It includes a sensor for noninvasive blood glucose and bilirubin measurement using near‑infrared spectroscopy and optical method, respectively, communicating with a smartphone.
It was observed that by increasing the glucose concentration, the output voltage of the sensor increases in transmittance mode and decreases in reflectance mode. Moreover, it was observed that by increasing the bilirubin concentration, the output voltage of sensor decreases in transmittance mode and increases in reflectance mode. In the collected data there was good correlations between voltage and concentration and their relationship were approximately linear. Therefore, it is possible to use noninvasive methods to predict the glucose or bilirubin concentration. In vivo experiments for glucose were carried out with 19 persons in training phase, and fve persons were used for testing the model. The glucose behavior model was built into the mobile application. The average glucose concentrations from the transmittance and reflectance mode were obtained. The average percentage error was 8.27 and root mean square error was 18.52 mg/dL.
From this research, it can be inferred that the noninvasive optical methods implemented on wireless sensors and smartphones could form a system that can be used at any time and any place in the future as an alternative to traditional invasive blood glucose and bilirubin measurement methods.

Tracheal sound analysis is a simple way to study the abnormalities of upper airway like airway obstruction. Hence, it may be an effective method for detection of alveolar hypoventilation and respiratory depression. This study was designed to investigate the importance of tracheal sound analysis to detect respiratory depression during cataract surgery under sedation.
After Institutional Ethical Committee approval and informed patients’ consent, we studied thirty adults American Society of Anesthesiologists I and II patients scheduled for cataract surgery under sedation anesthesia. Recording of tracheal sounds started 1 min before administration of sedative drugs using a microphone. Recorded sounds were examined by the anesthesiologist to detect periods of respiratory depression longer than 10 s. Then, tracheal sound signals converted to spectrogram images, and image processing was done to detect respiratory depression. Finally, depression periods detected from tracheal sound analysis were compared to the depression periods detected by the anesthesiologist.
We extracted fve features from spectrogram images of tracheal sounds for the detection of respiratory depression. Then, decision tree and support vector machine (SVM) with Radial Basis Function (RBF) kernel were used to classify the data using these features, where the designed decision tree outperforms the SVM with a sensitivity of 89% and specifcity of 97%.
The results of this study show that morphological processing of spectrogram images of tracheal sound signals from a microphone placed over suprasternal notch may reliably provide an early warning of respiratory depression and the onset of airway obstruction in patients under sedation.

Recently, a marginalized particle‑extended Kalman flter (MP‑EKF) has been proposed for electrocardiogram (ECG) signal denoising. Similar to particle flters, the performance of MP‑EKF relies heavily on the defnition of proper particle weighting strategy. In this paper, we aim to investigate the performance of MP‑EKF under different particle weighting strategies in both stationary and nonstationary noises. Some of these particle weighting strategies are introduced for the frst time for ECG denoising.
In this paper, the proposed particle weighting strategies use different mathematical functions to regulate the behaviors of particles based on noisy measurements and a synthetic ECG signal built using feature parameters of ECG dynamic model. One of these strategies is a fuzzy‑based particle weighting method that is defned to adapt its function based on different input signal‑to‑noise ratios (SNRs). To evaluate the proposed particle weighting strategies, the denoising performance of MP‑EKF was evaluated on MIT‑BIH normal sinus rhythm database at 11 different input SNRs and in four different types of artifcial and real noises. For quantitative comparison, the SNR improvement measure was used, and for qualitative comparison, the multi‑scale entropy‑based weighted distortion measure was used.
The experimental results revealed that the fuzzy‑based particle weighting strategy exhibited a very well and reliable performance in both stationary and nonstationary noisy environments.
We concluded that the fuzzy‑based particle weighting strategy is the best‑suited strategy for MP‑EKF framework because it adaptively and automatically regulates the behaviors of particles in different noisy environments.

Cancer is a complex disease which can engages the immune system of the patient. In this regard, determination of distinct immunosignatures for various cancers has received increasing interest recently. However, prediction accuracy and reproducibility of the computational methods are limited. In this article, we introduce a robust method for predicting eight types of cancers including astrocytoma, breast cancer, multiple myeloma, lung cancer, oligodendroglia, ovarian cancer, advanced pancreatic cancer, and Ewing sarcoma. In the proposed scheme, at frst, the database is normalized with a dictionary of normalization methods that are combined with particle swarm optimization (PSO) for selecting the best normalization method for each feature. Then, statistical feature selection methods are used to separate discriminative features and they were further improved by PSO with appropriate weights as the inputs of the classifcation system. Finally, the support vector machines, decision tree, and multilayer perceptron neural network were used as classifers. The performance of the hybrid predictor was assessed using the holdout method. According to this method, the minimum sensitivity, specifcity, precision, and accuracy of the proposed algorithm were 92.4 ± 1.1, 99.1 ± 1.1, 90.6 ± 2.1, and 98.3 ± 1.0, respectively, among the three types of classifcation that are used in our algorithm. The proposed algorithm considers all the circumstances and works with each feature in its special way. Thus, the proposed algorithm can be used as a promising framework for cancer prediction with immunosignature.

Bacterial sensors are recommended for medical sciences, pharmaceutical industries, food industries, and environmental monitoring due to low cost, high sensitivity, and appropriate response time. There are some advantages for using bacterial spores instead of bacteria in vegetative forms as spores remain alive without any nutrient for a long time and change to vegetative form when a suitable environment is provided for them. For biosensor fabrication, it is important to defne how the bacterial spores are delivered on the substrate media. In this study, a commercial inkjet printer (HP Deskjet 1510) was employed for transferring bacterial spores on a flexible substrate media, while in the previous studies, mostly, special printers were evaluated for transferring bacteria on rigid flms. Here, printed bacterial spores were used as calorimetric indicators for temperature. The custom‑made bio‑ink was made of bacterial spores along with gelling agent and pH indicator. The change in the temperature would have transformed bacterial spores into vegetative bacteria. This transformation would change bio‑ink pH to an acidic level that can be detected by a color change.

In the past, GRID therapy was used as a treatment modality for the treatment of bulky and deeply seated tumors with orthovoltage beams. Now and with the introduction of megavoltage beams to radiotherapy, some of the radiotherapy institutes use GRID therapy with megavoltage photons for the palliative treatment of bulky tumors. Since GRID can be a barrier for weakening the photoneutrons produced in the head of medical linear accelerators (LINAC), as well as a secondary source for producing photoneutrons, therefore, in terms of radiation protection, it is important to evaluate the GRID effect on photoneutron dose to the patients.
In this study, using the Monte Carlo code MCNPX, a full model of a LINAC was simulated and verifed. The neutron source strength of the LINAC (Q), the distributions of flux (φ), and ambient dose equivalent (H [10]) of neutrons were calculated on the treatment table in both cases of with/without the GRID. Finally, absorbed dose and dose equivalent of neutrons in some of the tissues/organs of MIRD phantom were computed with/without the GRID.
Our results indicate that the GRID increases the production of the photoneutrons in the LINAC head only by 0.3%. The calculations in the MIRD phantom show that neutron dose in the organs/tissues covered by the GRID is on average by 48% lower than in conventional radiotherapy. In addition, in the uncovered organs by the grid, this amount is reduced to 25%.
Based on the fndings of this study, in GRID therapy technique compared to conventional radiotherapy, the neutron dose in the tissues/organs of the body is dramatically reduced. Therefore, there will be no concern about the GRID effect on the increase of unwanted neutron dose, and consequently the risk of secondary cancer.

In recent years, the number of patients suffering from melanoma, as the deadliest type of skin cancer, has grown signifcantly in the world. The most common technique to observe and diagnosis of such cancer is the use of noninvasive dermoscope lens. Since this approach is based on the expert ocular inference, early stage of melanoma diagnosis is a diffcult task for dermatologist. The main purpose of this article is to introduce an effcient algorithm to analyze the dermoscopic images. The proposed algorithm consists of four stages including converting the image color space from the RGB to CIE, adjusting the color space by applying the combined histogram equalization and the Otsu thresholding‑based approach, border extraction of the lesion through the local Radon transform, and recognizing the melanoma and nonmelanoma lesions employing the ABCD rule. Simulation results in the designed user‑friendly software package environment confrmed that the proposed algorithm has the higher quantities of accuracy, sensitivity, and approximation correlation in comparison with the other state‑of‑the‑art methods. These values are obtained 98.81 (98.92), 94.85 89.51), and 90.99 (86.06) for melanoma (nonmelanoma) lesions, respectively.

With the advent of complex and precise radiation therapy techniques, the use of relatively small fields is needed. Using such field sizes can cause uncertainty in dosimetry; therefore, special attention is required both in dose calculations and measurements. There are several challenges in small-field dosimetry such as the steep gradient of the radiation field, volume averaging effect, lack of charged particle equilibrium, partial occlusion of radiation source, beam alignment, and unable to use a reference dosimeter. Due to these challenges, special dosimeters are needed for small-field dosimetry, and this review article discusses this topic.