Development a low-cost electrical impedance tomography system for non-invasively detecting abnormal in breast tissue - Phantom study-

Electrical Impedance Tomography (EIT) is known as non-invasive method to detect and classify the abnormal breast tissues. Reimaging conductivity distribution within an area of the subject reveal abnormal tissues inside that area. In this work, we have created a very low-cost system with a simple 16-electrode phantom for doing research purposes. The EIT data were measured and reconstructed with EIDORS software.

Design and Simulation of an Ultra-Wide Field Optical Coherence Tomography Retinal Imaging System

Peripheral retinal imaging is a unique approach for assessing and monitoring ocular diseases. In this paper, we proposed a design for an optical coherence tomography system to accomplish ultrawide field (>120°) retinal imaging without montages. Scanning of the sample arm was achieved via two ellipsoidal mirrors. The optical design software Zemax and an eye model were used to estimate the inherent aberrations in the system and the optical performance of retinal imaging. Simulation results of the aberrations in the designed system indicated that the designed system can achieve an unprecedented imaging field of view (FOV) while maintaining acceptable resolution without sacrificing the working distance. This work suggests that ultrawide field optical coherence tomography retinal imaging is achievable, which is highly important for the diagnosis and treatment of ocular—especially peripheral—retinopathy.

Multifrequency Impedance Tomography System for Research on Environmental and Thermal Processes

The possibility for spatial and temporal monitoring of environmental, chemical or thermal processes is of high importance for their better understanding thus control and optimization. Therefore, measurement methods that enable such opportunities might be especially valuable for researchers and process engineers. For this reason, in this paper the novel Electrical Impedance Tomography system is proposed that enables the visualization of the processes in which the electrical conductivity of material is changing. The proposed EIT system is based mostly on general purpose equipment. It consists of three laboratory-grade devices: a signal generator, a switching device and a data acquisition card for voltage measurement. In addition to those devices, the current source was constructed to complete the system. The EIT system was designed to have the ability of sourcing the current of frequency up to 250 kHz. A set of validation experiments were carried out to verify the EIT system accuracy. The validation tests consisted of object detection, distinguishing between objects of different conductivity, multifrequency imaging and visualization of slow-changing processes. The obtained results were also compared with the numerical simulations. The proposed system was proven to have the ability of correct imaging of irregularity inside the area of the sensor.

Effects of 0.01% Atropine Instillation Assessed Using Swept-Source Anterior Segment Optical Coherence Tomography

In this paper, we assessed the short-term effects of 0.01% atropine eye drops on anterior segment parameters by performing ocular biometry using a swept-source anterior segment optical coherence tomography system (AS-OCT). We recruited 17 healthy volunteers (10 men and 7 women aged 24–35 years) with no history of eye disease. Participants without accommodative demand demonstrated significant mydriasis 1 h after the atropine instillation (4.58 ± 0.77 to 5.41 ± 0.83 mm). Pupil diameters with a 5 diopter (D) accommodative stimulus at 1 h (4.70 ± 1.13 mm) and 24 h (4.05 ± 1.06 mm) after atropine instillation were significantly larger than those at baseline (3.71 ± 0.84 mm). Barring pupil diameter, no other biometric parameters significantly changed at any point in time after atropine instillation without accommodative demand. However, with an accommodative stimulus, anterior chamber depth (ACD) at 1 h and posterior curvature of the lens at 1 and 24 h were both significantly larger than those before atropine instillation. Using AS-OCT, we detected a slight decrease in the accommodation response of ocular biometric components evoked by 0.01% atropine instillation. Morphologically, our measurements suggested a change in the ACD and horizontal radius of the lens’ posterior surface curvatures due to the subtle reduction of accommodation.