BIOMEDICAL TECHNIQUES

It involves the application of the principles of natural sciences especially biology and physiology to clinical medicines. Clinical medicines utilises various techniques for numerous diagnostic purposes.

The biomedical techniques are listed below:

1- ANGIOPLASTY

 

It is a technique of mechanically widening the narrowed or obstructed arteries, the latter  typically being a result of atherosclerosis. An empty and collapsed balloon on a guide wire, known as a balloon catheter, is passed into the narrowed locations and then inflated to a fixed size using water pressure some 75 – 500 times of normal blood pressure(6 – 20 Atm). The balloons crushes the fatty deposits, opening up the blood vessel for improved flow, and the balloon is then deflated and withdrawn. A stent may or may not be inserted at the time of ballooning, to ensure the vessel remains open.

 

2- ORGAN TRANSPLANTATION

It is the transfer of an organ from one body to another or from a donar site to another location on the patient’s own body, for the purpose of replacing the recipient’s damaged or absent organ.

The emerging field of regenerative medicine is allowing scientists and engineers to create organs to be re-grown from the patient’s own cells (stem cells, or cells extracted from the falling organs). Organs and/or tissues that are transplanted within the same person’s body are called autografts. Transplants that are performed between two subjects of the same species are called allografts. Allografts can either be from a living or cadaveric source.

3- X- RAY RADIOGRAPHY

X-rays were discovered by Roentgen in 1895. Radiography is basically an imaging technique that uses electromagnetic radiations which has the ability to penetrate the materials that do not transmit visible light. In this, an X-ray beam is allowed to pass through the patient on to a photographic plate.

It is commonly employed for diagnosing diseases of the heart, lungs and bones, etc.

4- ANGIOGRAPHY

It is used to visualise the inside or lumen of blood vessels and organs of the body, particularly in arteries, veins and heart chambers. Traditionally, it is done by introducing a radio opaque, i.e., contrasting agent (e.g., iodine) or fluoroscopic cemical. In this image intensifiers are used to provide real image and cathode ray tube (CRT) are used to view the images.

5- COMPUTED TOMOGRAPHIC SCANNING (CT SCAN)

 

It is a special radiographic technique which combines X-ray imaging with computer techniques to produce and visualise clearly two or three dimentional cross sectioned image of deep internal organs that could never be attained by conventional X-ray methods.

Since, the technique combines the use of X-ray with computers and hence, it is called Computed Tomography(CT) or Computed Axial Tomography (CAT). CT scan provides broad and detailed information than obtained by X-rays.

6- MAGNETIC RESONANCE IMAGING (MRI)

MRI is a very expensive technique. This medical test is used by the doctors to diagnose and treat diseases that cannot be accurately diagnosed by X-rays, ultrasounds and CT scan. It is mainly used to detect lesions of multiple sclerosis on brain and spinal cord and also to examine joint injuries and slip disk conditions. It can have beneficial application in differentiating the white and grey matter of brain. It can also be helpful in examination of cancerous tumours and to measure blood flow.

MRI depends on the phenomenon of nuclear magnetic resonance (i.e., magnetic field and radio frequency pulses) because it is based on the fact that some nuclei behave like tiny magnets. The MRI technique uses the natural behaviour of the protons (nuclei) of H atoms, when they are introduced to a very strong magnetic fields and radio waves.

In our body, hydrogen atoms in water molecules act like the abundant source of protons. It reflects difference in the water content of tissue. It allows MRI to differentiate between water poor and water rich tissue. By this technique, the detailed picture of organs such as heart, kidney, liver, pancreas are obtained on a computer screen.

7- ULTRASOUND IMAGING (SONOGRAPHY)

 

This technique uses ultrasound for producing images of internal body parts. Ultrasound is mainly a high frequency sound waves. The humans cannot hear it. The limit varies from person to person and is approximately 20 kHz (20,000 Hz) in healthy young adults. In sonography, inaudible high frequency sound waves in the range of

1-15 MHz are produced through a physical phenomenon called piezo electric effect. It is very useful in diagnosing kidney stones, gall bladder stones, liver cirrhosis, obstructions in intestine, uterus, etc. It also reveals pregnancy and foetal abnormalities and ultrasound also plays an important role in studying heart functioning by ecocardiography.

8- ELECTROENCEPHALOGRAPHY (EEG)

This test is performed to measure the electrical activity of the brain, i.e., voltage fluctuations resulting from ionic current flow within the neurons of the brain. It is mainly used to diagnose epilepsy, brain diseases such as encephalitis, dementia, head injuries, brain tumours, insomnia, brain hoemorrhage, etc.

It is also helpful in determining the level of brain functions in people who are in coma. The functioning of EEG depends on the neurons of the brain that generate electrical impulses which fluctuate rhythmically in a specific manner.

These neurons conduct four types of waves in different states of nervous activity.

9- IMMUNOTHERAPY

It is a medical term defined as the treatment of disease by inducing, enhancing or suppressing an immune response. Immunotherapies designed to elicit or amplify an immune response are classified as activation immunotherapies, while the immunotherapies that reduce or suppress an immune response are classified as suppression immunotherapies.

10- HORMONE THERAPY

It is the use of hormones in medical treatment.

Some useful examples includes:

• Hormonal therapy for cancer.
• Hormone therapy for prostate cancer refers to androgen deprivation therapy.
• Hormone replacement therapy (menopause) connected to menopause.
• Testosterone replacement in males with low levels due to disease or ageing.
• Hormone therapy in Klinefelter’s syndrome.
• Hormone therapy in Turner’s syndrome.

11- POSITRON EMISSION TOMOGRAPHY (PET)

It is a nuclear medical imaging technique that produces a 3-D image or picture of functional processes in the body. The system detects pairs of gamma rays, emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule. 3-D images of tracer concentration within the body are then constructed by computer analysis. In modern scanners, three dimentional imaging is often accomplised with the aid of a CT X-ray scan performed on the patients during the same session in the same machine.

12- CORONARY ARTERY BYPASS SURGERY

It is a surgical procedure performed to relieve angina and reduce the risk of death from coronary artery disease. Arteries or veins from elsewhere in the patient’s body are grafted to the coronary arteries to bypass atherosclerotic narrowings and improve the blood supply to the coronary artery supplying the myocardium (heart muscle). This surgery is usually performed with the heart stopped, necessitating the usage of cardiopulmonary bypass. Techniques are available to perform CABG on a beating heart so called off-pump surgery.

 

SOME DIAGNOSTIC TECHNIQUES AVAILABLE IN KITS

• ENZYME LINKED IMMUNOSORBENT ASSAY(ELISA)

It is a popular format of a ‘wet-lab’ type analytical assay that uses one sub-type of heterogeneous, solid-phase Enzyme Immuno Assay (EIA) to detect the presence of a substance in a liquid sample or wet sample.

The ELISA has been used as a  diagnostic tool in medicine and plant pathology, as well as a quality-control check in various industries. It is mainly used as an initial screening or HIV detection on the basic of antigen-antibody interaction.

• PREGNANCY TEST KITS

This kit is usually used to test or determine whether a woman is pregnant or not. It uses markers, i.e., urine and blood that indicates pregnancy and require them as sampling substances. The modern test for pregnancy that provides the quickest result after fertilisation is a rosette inhibition assay for early pregnancy factor(EPF). EPF can be detected in blood within 48 hrs of fertilisation. However testing for EPF is expensive and time consuming.

The kit measures the hormone, Human Chorionic Gonadotropsin(hCG) in urine.