Category: Biomedical Measurements
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The General Principle of Fiber Optic-based Sensor
Optical sensors are typically interfaced with an optical unit. This optical component supplies the excitation light, which may be from a monochromatic source such as a diode laser or from a broadband source e.g. quartz-halogen that is filtered to provide a narrow bandwidth of excitation. Typically, two wavelengths of light are employed: one that is…
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Micrometer and Nanometer Biomedical Sensing Applications
The advancements in microtechnology and, in particular, nanotechnology are transforming the fields of biosensors, prosthesis & implants and medical diagnostics. In medical diagnostics, these devices are being employed in combination with optical biosensing for external, lab-on-a-chip, high throughput screening for analysing blood and other samples. Several companies and researchers are developing optically based nanotechnology applications…
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Contrast Agents Commonly Applied In Medical Imaging
Contrast agents emphasize or magnify the physiological features or functions that would otherwise, be invisible, weak or obscured in images. Contrast agents are commonly applied in vasculature and also employed in applications where the uptake of an agent by an organ is used to indicate the degree of functional or metabolic activity. Each agent is…
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Clinical Applications of NTC Thermistors
Thermistors are certainly the most used transducers for medical temperature measurements. Their properties facilitate clinically difficult measurements that include: hypothermia, transcutaneous measurements during cardiopulmonary bypass, testicular temperature measurements in reproductive medicine, continuous monitoring of preterm infants and personal heat strain monitoring in occupational medicine. Thermistors are also extensively used in a variety of clinical and…
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Blood Glucose Sensors
The accurate measurement of blood glucose is essential in the diagnosis and long term management of diabetes. In this article, we discuss the use of biosensors for the continuous measurement of glucose levels in the blood and other body fluids. Glucose is the main circulating carbohydrate in the body. In normal individuals, the concentration of…
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Key Features of ECG Amplifiers
A differential amplifier is employed as ECG amplifier instead of the typical electronic amplifiers. The reason why the electronic amplifiers aren’t employed in electrocardiograph (ECG) is because they create an interference problem when they are used to measure small bioelectric potentials. A differential amplifier can be considered as two amplifiers having separate inputs but they…
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Principle Parts and Types of ECG Recorders
Building Blocks of an ECG System In Electrocardiography (ECG) recorder five leads from the patient are connected to the ECG recorder through a selector switch to obtain 12 lead configurations as illustrated below: A standard voltage of 1 mV is used to calibrate the recorder. The output from the lead selector switch is amplified using…
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How Partial Pressure of Oxygen and Carbon dioxide in the Blood is Measured
The measurement of partial pressure of oxygen and carbon dioxide in the blood is one of the key physiological chemical measurements. The partial pressure of a dissolved gas is defined as the contribution of this dissolved gas to the total pressure of all dissolved gases in the blood. Hence, the partial pressure of a gas…
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The Function of Impedance Pneumograph In Respiration Measurements
Impedance pneumography is an indirect method for the measurement of respiration. This measurement is performed by the impedance pneumograph which measures the respiratory volume and rate through the relationship between respiratory depth and thoracic impedance change. Impedance pneumography avoids burdening the subject with spirometers, tubes, and flowmeters; does not hinder respiration and has minimal effect…