Tomography: what is it for? Who can do it?

Due to technological advances, it is possible to perform complex tests and diagnose diseases or monitor the health of each element that forms our body. One of the tests that allows these processes is computed tomography.

Presented in the 70s, tomography is an examination considered non-invasive and is able to identify changes in internal organs, serving for the diagnosis of several diseases. Find out more about this exam in the text below!


What is tomography?

The computed tomography exam allows detailed images of different tissues and organs.

Computed tomography (CT) is an examination performed by means of x-ray waves that when they reach the body form images that can be seen on a monitor. It is possible to perform tomography in different parts of the body, such as the head, eyes, chest, abdomen, hips, arms and legs.

This test is considered to be safe and reliable, as it allows an accurate diagnosis (or monitoring), since it is not as sensitive to the patient’s movements during the process, unlike what happens with magnetic resonance imaging, for example.

In addition, through the exam, it is possible to analyze in detail structures, tissues and organs, being ideal to identify changes in the body early.

When carrying out the examination, it is common for doubts to arise regarding the amount of radiation used, however those considered as not sensitive to electromagnetic waves, can perform the tomography normally, since the level of radiation is controlled and adequate so as not to affect the patient.

In cases of radiosensitive people, such as children and pregnant women, it is necessary to be more careful in this matter. In general, it is indicated that these groups opt for magnetic resonance or ultrasound, since the level of radiation is lower. In this way, complications are avoided.

What is the tomography exam for?

The computed tomography exam serves to diagnose different muscle and bone diseases that are compromising the health and well-being of the patient or to monitor the progress of these diseases.

It is usually indicated in these cases because it allows a 360º view (degrees) of Organs analyzed organs, contributing for the medical evaluation to be detailed and accurate.

Among the changes that can be identified through tomography are: tumors, clots and infections.

When do I need to do it?

Computed tomography is not considered a routine exam, so it is done only by medical indication. Therefore, it is common for the patient to undergo assessments of clinical status, health history, among other checks before performing the exam.

In general, the most suitable case for tomography is when there are suspicions about the presence of a tumor (benign or malignant) and cancer , as well as the evolution and stages of these diseases.

However, there are other situations in which the exam can be requested, such as:

  • Cerebrovascular accident ( stroke ) and stroke;
  • Infections, injuries and clots;
  • Aneurysms;
  • Hemorrhages;
  • Perforation of intestinal loops;
  • Heart attacks ;
  • Pulmonary embolisms;
  • Cerebral edema.

In these situations, tomography is not usually the first examination option performed, however, as a way of finding out in greater detail, tomography is the best choice.

What types of tomography?

There are different types of computed tomography, which vary according to the region of the body in which it is done. Some of them are:

Skull tomography – called cranial angiotomography, the tomography performed on the skull is prescribed in order to identify hemorrhages, traumas, infections, hydrocephalus , aneurysms, among other changes.

Face tomography  makes it possible to view fractures in the mandible and maxilla, in addition to nasal deviations.   

Eye tomography – with optical coherence tomography or (OCT) it is possible to have a cross-sectional image of the retina and thus assess whether there are changes in it.

Abdominal tomography – indicated to assess the presence and evolution of tumors in the abdominal and pelvic region, and can also be useful in the diagnosis of appendicitis, lithiasis, renal malformation, pancreatitis , pseudocysts, liver damage, cirrhosis and hemangioma .

Chest tomography –  allows to identify diseases that affect the lung, rib cage and cardiovascular system.

Spine tomography – it is possible to view areas such as the cervical, lumbar, dorsal and sacral loin, and helps in the diagnosis of fractures and diseases linked to poor posture.

Tomography of the upper and lower limbs – serves to recognize fractures, muscle injuries, tumors and infections that affect arms and legs.

How is it done?

It is called a tomograph is the equipment used for the exam.

Computed tomography is an examination that is considered minimally invasive and does not cause pain. It is done through the use of special equipment that allows the formation and visualization of images, which are the tomograph and programmed computers.

The tomograph is a tunnel-shaped device with a narrow central opening through which an examination stretcher passes  where the patient remains during the entire process.

Thus, to perform the examination, the patient is instructed to lie down on the stretcher, which will then be moved into the scanner, where electromagnetic rays will scan the desired body region, which can be seen almost instantly on the monitor.

It is worth remembering that after lying on the table the patient must remain in the position, without making any sudden movements until the doctor requests, as this way it is possible to guarantee accurate and sharp images.

In some cases, it may be necessary for the person to learn to breathe while the images are taken.

In addition, the patient should not be wearing any metal accessories (bra, piercings, earrings, jewelry, among others), nor with clothes that have buttons or zippers. Usually, the site provides an apron to be used during the exam.

The computed tomography exam is not usually long, taking, on average, 10 to 30 minutes. However, depending on the area to be examined, the time may increase or decrease.

What is contrast tomography?

Contrast tomography means the use of some element that, when hit by the x-ray waves, remains opaque, that is, a radiopaque substance.

This element is administered so that the observation of some organs and tissues of the body is more efficient, since sometimes there is no opacity in these structures, preventing the complete visualization and the accurate diagnosis.

One of the most widely used contrast formulas is iodine with barium sulfate, with iodine being the radiopaque element.

The contrast can be applied in different ways such as orally, parenteral (injections into the vein), endocavitary (holes like the anus and vagina) and intracavitary (in the wall that will be analyzed during the exam).

The dose of contrast used depends on the area in which it will be examined and will follow the guidelines of the Brazilian College of Radiology and Diagnostic Imaging (CBR).

In general, the contrast is indicated by a doctor when there is a need to observe body tissues and the vascularization (blood flows) of these structures in greater detail.

What are the precautions to do the tomography?

To avoid problems, before taking the exam, it is necessary to provide information about the health condition.

The care that must be taken to perform tomography will depend on the type and specific guidelines of each clinic or laboratory where the exam will be performed.

To help determine these guidelines, it is common for the patient to have to fill out a form regarding their health condition before having a CT scan. Typically, the recommended care (depending on the case) is:

  • Fasting for 8 hours (when the use of contrast is necessary);
  • Suspension of medications (mainly for diabetes);
  • Use of laxatives (when the area examined belongs to the digestive system).

Who can do the tomography?

Computed tomography can be performed by most people, with the exception of those who are sensitive to x-ray waves and groups such as children, pregnant women and breastfeeding women who may experience negative reactions after the exam.

Therefore, it is essential to inform the doctor in case of sensitivity to electromagnetic waves and suspected pregnancy. In this way, the professional can indicate other forms of imaging exam, ensuring the patient’s health.

How much?

On average, the price of computed tomography is from R $ 200 to R $ 300 and can be done in radiology and diagnostic imaging clinics. However, in some cases, depending on the area to be examined, the amount can reach R $ 700.

Tomography can also be done free of charge by the Unified Health System (SUS), according to medical advice.

It is worth mentioning that it is necessary to take some important papers on the day of the tomography, such as, for example, the medical request requesting the exam, original documents with photos to perform the registration. Being in the clinic, it is necessary to complete a questionnaire before the exam.

The improvement of equipment by researchers and technicians in the health field, contributes to that image exams are increasingly efficient to identify diseases and health changes, collaborating for an accurate diagnosis.