Medical Imaging Techniques and Biological Agents

Radiography: First Imaging Technique

Radiography is the first imaging technique developed. It is based on the use of X-rays. X-rays are a type of radiation with much energy, which causes some objects to pass through easily. Abuse of X-rays poses a risk of producing cancer. This technique is not recommended for pregnant women and small children.

Computerized Tomography (CT)

Computerized Tomography (CT) is based on taking multiple X-rays of a body area with a special device where the X-ray rotates around the patient. All images are combined using a PC. This technique provides detailed images of the body's interior. Its major drawback is that it requires using large amounts of radiation.

Magnetic Resonance Imaging (MRI)

Magnetic Resonance Imaging (MRI) is a large tube-shaped machine that creates a strong magnetic field around the patient. This technique does not use radiation, therefore it has less risk, but it cannot be used in people with certain objects like pacemakers or prostheses.

Ultrasound Imaging

Ultrasound is based on the utilization of very high-frequency sounds inaudible to people. The ultrasound waves are focused on the patient's body, and the apparatus receives the echoes that occur in various structures of the body to create an internal image.

Nuclear Medicine Scans

Nuclear Medicine is based on the introduction of various radioactive substances to examine how they are distributed throughout the body. These substances emit gamma rays, which are captured by a detector called a gamma camera. The images obtained, called scans, inform us about the functioning of the organs.

Bacteria: Unicellular Organisms

Bacteria are unicellular organisms with no nucleus. When bacteria multiply inside the body, they can destroy cells and nearby tissue. Additionally, they produce various substances called toxins. These toxins are distributed through the bloodstream and cause more serious symptoms of the disease.

Viruses: Replication Process

Viruses cannot reproduce on their own. To reproduce, they must introduce themselves within a cell, inside which they replicate, producing large numbers of viruses.

Protozoa: Disease-Causing Species

Protozoa are unicellular organisms with a defined nucleus. Only about 20 species cause disease in humans, but a quarter of humanity is affected by them.

T Lymphocytes and Immune Defense

When a virus affects a cell, it leaves proteins from its envelope on the cell surface. T lymphocytes recognize these proteins and destroy the infected cells where the virus is found. This prevents the virus from replicating. T lymphocytes are similar to B lymphocytes in that each lymphocyte recognizes a specific antigen and becomes activated when it recognizes it. T lymphocytes also regulate the functioning of immune system elements, making them key in defending the body.