Radiology departments as well as the physicians dedicated to this specialty are of utmost importance in any medical service.
In many cases, diseases need to be confirmed by means of imaging tests, along with making differential diagnoses and knowing what is normal and abnormal in the body.
Specialists in radiology are essential to be able to diagnose findings seen through any of its working tools.
History of radiology
The rise of conventional radiology dates back to the end of the 19th century, when the German physicist Wilhelm Roentgen discovered X-rays.
According to historical records, Roentgen was in a dark room with only a fluorescent screen, a Crookes tube, an induction coil and black cardboard.
By means of the Crookes tube and the inductor coil, light was created that was able to pass through the black cardboard and reflect the fluorescence of the screen.
These rays were able to pass through other solid materials with great ease, except for metal and dense objects.
When he saw that this light passed through matter, he saw the possibility of its implementation in medicine, a fact that earned him a Nobel Prize in physics in 1901.
At that time, the physician had a strong limitation when investigating the causes of a disease and therefore the interior of the organism to know what was happening.
Relevant information before discussing the different modalities and their invention.
Each modality or study method has its distinct advantages and disadvantages, indications and contraindications, study purpose, cost-effectiveness, and specificity and sensitivity.
Study purpose refers to the fact that some imaging studies are of choice and routine over others.
For example, plain radiography is the most commonly used, but when this study does not reveal enough, the implementation of CT or MRI is contemplated.
Likewise, each diagnostic method has its own specificity and sensitivity.
Specificity is defined by the probability of a healthy person having a negative result, i.e. not having the disease.
Sensitivity, on the other hand, represents the ability of each study to be positive in detecting abnormalities.
The different radiology modalities
Created in 1895 and already mentioned, it was the first diagnostic imaging method invented and was born at the University of Würzburg, Germany.
Nowadays, conventional radiography is used to obtain images of bones, soft components, thorax contents as well as the abdomen.
The values attributed to radiography are only two, radiolucent, for dense structures with little visible oxygen, representing the color white.
And also radiopaque structures (with the highest expression of oxygen), such as the interior of organs and soft tissues, seen in black and gray color.
The first mammogram was developed in 1951 by the physicist and physician Charles Gros in order to find benign or malignant tumors in the breast.
Computed Tomography (CT)
CT was designed by Godfrey Hunsfield and Allan Cormack in 1972. They were based on the design of radiography.
Unlike radiography, which offers only one image, CT is capable of generating thousands of images at different angles and with greater definition.
Of helical CT it is important to highlight the wide availability of studies, such as those specific to the abdomen and pelvis, skull, spine, orbital (eye) and thorax.
This allows, in addition to obtaining sharper images, reconstructions in the third dimension.
It has its own statistical value, the Hunsfield unit, to represent CT hyperdensity (white) and hypodensity (black).
Magnetic Resonance Imaging (MRI)
The appearance of MRI in 1972 is somewhat peculiar, since it was not designed for medical research.
In general, atoms act as magnetized particles, a fact that was of interest to the physicist Paul C. Lauterbur, creator of nuclear magnetic resonance and researcher of chemical reactions.
However, the use of MRI in medicine arose thanks to an article by Raymond V. Damadian, a physician who described the use of magnetic fields to differentiate normal tissue from tumor tissue.
The first stages of implementing MRI were not very satisfactory, but the support of physicist Peter Mansfield made it possible to perfect this imaging method.
Thus, throughout the 1980s, the first equipment for magnetic resonance imaging was developed.
The magnetic resonance images of the body are elaborated from magnetic waves processed in a computer.
The information is represented by hypointense (black), isointense (gray) and hyperintense (white) tones.
One of the most important points is that it does not use ionic radiation, which is used by X-rays and CT.
The ultrasound or ultrasonography we know today is totally different from the one used more than a century ago.
Between 1880 and 1881 saw the development of the first US created by Jacques and Pierre Curie, using the electric field generated to experiment on quartz and tourmaline crystals.
However, the first US of application in medicine was until 1951, this ultrasound consisted of a transducer capable of generating ultrasonic pulses on the tissue.
All this to generate composite images from the “echoes” recorded in real time, a task that has been maintained to date.
Something to highlight about ultrasound is its particular safety, since it is even safer than tomography, X-rays and magnetic resonance.
The sound frequencies necessary to generate the images (above 20,000 Hz) are not harmful to humans, nor does it use radiation, and it is much less costly and cumbersome than MRI.
Nuclear medicine is a specialty of medicine and is complemented by radiology, since it is used for the evaluation and diagnosis of diseases.
This branch had a great boom after the discovery of several radiations. Roentgen and X-rays in 1895, Henri Becquerel with uranium (1896) and Marie Curie with natural radioactivity (1898).
In addition, Irene Joliot Curie, who discovered artificial radioactivity in 1934, initiated nuclear medicine as a diagnostic method.
Following these contributions, many other physicists and physicians have investigated radiotracers for medical purposes.
Nuclear medicine is based on the administration of such radiotracers or radiopharmaceuticals into the body to examine a specific area of the body.
These compounds are capable of accumulating on tumor and inflammatory processes, which are highlighted on the images to be examined.
To appreciate the images, positron emission tomography (PET-CT) or single photon emission tomography (SPECT-CT) is used.
Also, as a comparative method, associating it with CT or MRI scans facilitates diagnosis.
Other radiology modalities
They are administered to enhance the imaging findings, since they highlight the areas with involvement seen by any of the radiological modalities.
These contrast materials can be taken orally, rectally or intravenously, and are absorbed by the body and then discarded in the urine and feces.
Among the most commonly used contrasts are barium sulfate, gadolinium, microbubbles and technetium.
To a certain extent, they are safe for the body, because overdose or contrast allergies are the most common causes of side effects.
Beginning in 1963, physicians Cameron and Sorenson described a method for measuring bone mineral density from radiation.
Also known as X-ray absorptiometry, it is the method of choice for the diagnosis of osteoporosis in predisposed individuals.
It estimates bone mineral content from radioisotopes that allow visualization of bone composition, whether increased, normal or reduced.
Its implementation requires X-rays, CT or rarely ultrasound.
Dr. Antonio Caetano, a neurologist, developed the first angiography in 1927, introducing sodium iodide as a contrast method.
Angiographies are of importance in the study of diseases of the vascular system. It is performed by means of X-ray, CT or MRI.
For its use, a catheter containing contrast material is also needed to observe the blood circulation of the area to be studied.
It helps to identify aneurysms, atherosclerotic plaques, malformations, serves as a guide for reconstruction and stent placement, among many other functions.
Born since the discovery of X-rays with the physicist Wilhelm Roentgen and perfected by Thomas Edison.
It is a technique to observe in real time the graphic representation of the human body by means of X-rays and contrasted media.
It is useful for medical interventions and diagnostic tests, however, radiation exposure must be taken into account.
In Grupo PACS and Teleradiology we are committed to provide updates on diagnostic methods, and this time talking about the past, inventions and creators helps us to give a basis for enrichment about radiology.