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Inform yourself and get ready for your imaging study

Información relevante en forma de guías para esclarecer dudas sobre tus estudios

At Medica Sur Hospitals, not only do we deliver proper care to patients, but also relevant information in the form of guides with which every doubt regarding the imaging studies requested by their physician can be clarified. 

Questions about side effects, radiation effects, how the procedure is performed, etc. will have an answer in this explanatory guide, where you will have the chance to inform yourself before undergoing any diagnostic imaging study.

 Frequently asked questions

What are the benefits of DSCT?

Dual Source Computed Tomography is regarded as one of the top 5 medical advances in the last 40 years. DSCT has proven to be a valuable medical diagnostic tool, which won its inventors the Nobel Prize in Medicine in 1979.

Some of its benefits consist of a more efficient way to manage the procedures to be performed on patients.

  • It can be determined when surgery is needed
  • Reduces the need for exploratory surgeries
  • Better diagnosis and treatment of cancer
  • Reduces hospitalization period
  • Monitoring on treatments such as: injuries, heart diseases, and cerebrovascular accidents.
  • Better diagnosis to refer the patient to the right area of care, such as the intensive care units.

DSCT provides medical information different from that of diagnostic imaging studies such as ultrasounds, MRI, PET-CT or nuclear medicine, for it provides data which can rapidly be interpreted by the physician to assess an emergency situation, for example, after an accident, the patient can be scanned and it can be determined whether they have an internal hemorrhage and requires an emergency surgery. Its main advantages are:

  • Quick image acquisition
  • Large amounts of clear and specific information
  • View of a great part of the body

How does DSCT work?

The main function of DSCT is image taking of internal body structures.

In conventional x-ray imaging, the structures and organs are superimposed, for example, the ribs are superimposed upon the lungs and the heart. Hence in x-ray imaging the organs to be studied by the physician are often obscured by other organs or bones, which make the diagnosis difficult.  In turn, in DSCT imaging the superimposed structures are eliminated, therefore the internal anatomy is visible and evident to the eyes of physicians.

In DSCT, the x-ray tube rotates around the patient in a way that several images are taken from different angles. These images are stored in a computer which analyzes them to create a new image by eliminating everything that is covering the organ to be analyzed.


This allows physicians and radiologists to use this information to:

  • Know what the medical problem is
  • How extensive it is
  • Where it is exactly located
  • Find abnormalities
  • Other important details

Examination by this means enables the acquisition of information within seconds.

 How much radiation exposure is needed?

The amount of medical radiation or exposure to radiation will depend on your health needs, and that will be all you will be requiring. For example:

  • Low: x-ray for an ankle fracture.
  • Moderate: an appendicitis computed tomography.
  • High: multiple computed tomography after trauma.

Therefore, there is not a fixed answer, so it is recommendable to ask your physician and radiologist about the benefits of your study, as well as the amount of exposure needed to get the results desired. 

Does radiation have risks depending on age?

The amount of radiation needed to obtain images in children is much lower than in adults. Therefore, the risk associated with the diagnostic study in children does not have to be higher than that of adults, it is usually lower.
The risks for children and teenagers are higher, when exposed to the same amount of radiation as for adults. Children grow rapidly and their cells are more sensitive to radiation. Due to the fact that radiation effects take years to develop, the youth of children helps to prevent these possible effects from developing.
In elderly patients, the exposure to radiation becomes a minor problems, for body tissues in old age are less sensitive to the effects of radiation. Therefore, studies such as DSCT may play an important role in the diagnosis and treatment of elderly patients.


How are………studies performed?


It is a study that combines Computed Tomography (CT) with Positron Emission Tomography (PET), also called PET diagnostic imaging or PET exploration, in the same image and which constitutes a type of nuclear medicine imaging diagnosis.

Nuclear Medicine constitutes a subspecialty of the field of medical imaging which uses very small amounts of radioactive material to diagnose or treat a variety of diseases, including many several types of cancer, heart disease, and other particular abnormalities inside the body.

The procedures by nuclear medicine imaging or radionuclide are not invasive, with the exception of intravenous injections, and they are normally painless medical studies that help physicians to diagnose health problems.


Uses of PET-CT

For it is an effective diagnostic method, PET/CT may be used for oncologic studies (tumors), neurologic, psychiatric, infectious, autoimmune, cardiologic, or angiographic (blood vessels) both in adult patients and pediatric ones. 

PET and PET/CT studies are performed to:


  • Detect cancer
  • Determine whether cancer has spread in the body
  • Assess the effectiveness of a treatment plan such as cancer therapy.
  • Determine the return of cancer after treatment
  • Determine blood flow towards the cardiac muscle
  • Determine the effects of a cardiac arrest or myocardial infarction, on areas of the heart.
  • Identify areas of the cardiac muscle which will benefit from procedures such as angioplasty or coronary bypass surgery (combined with a myocardial perfusion study)
  • Assess brain abnormalities such as tumors, memory disorders and seizures, among other disorders of the central nervous system.
  • Schematize normal human brain and cardiac function.

The combination of these two techniques makes this study more reliable, diagnostic, and easy to interpret than if both studies were performed separately.

Previous preparation

  • Before the study these recommendations shall be followed in order for the diagnosis to be as accurate as possible.
  • You should inform your doctor and technician performing the study of any medications you are taking, including vitamins and herbal supplements, as well as whether you have any allergies or about recent diseases or health problems.
  • If you are breastfeeding it is advisable to drain the milk beforehand and store it for later use, for you will not be able to breastfeed until the PET radiopharmaceutical and the CT contrast agent are no longer in your body.
  • Metal objects such as jewelry, eyeglasses, dentures, and hairpins should be left at home or be removed prior to your exam, as well as hearing aids and removable dental work.
  • You will be asked not to eat nor drink anything for several hours before a whole-body PET/CT examination, for this might alter the distribution of the pet tracer in your body and can lead to a suboptimal scan.
  • You should not drink any liquids containing sugars or calories for several hours before the scan.
  • If you are diabetic, you may be given special instructions.
  • You should inform your physician of any medications you are taking and if you have any allergies, especially to contrast materials, iodine, or seafood.
  • You will be asked and checked for any conditions that you may have that may increase the risk of using intravenous contrast material.

How is the PET-CT procedure performed?

Nuclear medicine imaging is usually performed on an outpatient basis, but is often performed on hospitalized patients as well. In order for you to have a clearer picture of how this procedure is performed, here is an outline on how it is carried out:

  • You will be positioned on an examination table. If necessary, a nurse or technologist will insert an intravenous line into a vein in your hand or arm.
  • Depending on the type of nuclear medicine exam you are undergoing, the dose of radiotracer is then injected intravenously, swallowed or inhaled as a gas.
  • It will take approximately 60 minutes for the radiotracer to travel through your body and to be absorbed by the organ or tissue being studied. You will be asked to rest quietly, avoiding movement and talking. You may be asked to drink some contrast material that will localize in the intestines and help the radiologist interpreting the study.
  • You will then be moved into the PET/CT scanner and the imaging will begin. You will need to remain still during imaging. The CT exam will be done first, followed by the PET scan.
  • Total scanning time is approximately 30 minutes.
  • The actual CT scanning takes less than two minutes. The PET scan takes 20-30 minutes.
  • Depending on which organ or tissue is being examined, additional tests involving other tracers or drugs may be used, which could lengthen the procedure time to three hours. When the examination is completed, you may be asked to wait until the technologist checks the images in case additional images are needed.
  • If you had an intravenous line for the procedure, it will be removed once the study is completed.


Digital mammography

A mammography is a study which women should undergo periodically as prevention for timely detection of breast cancer or any other pathology.

Digital mammography is a mammography system in which the x-ray film is replaced by solid state detectors which convert x-rays into electrical signals. These detectors are similar to those found in digital cameras. The electrical signals are used to produce images of the breast that can be seen on a computer screen or printed on special film similar to conventional mammograms. From the patient's point of view, having a digital mammogram is essentially the same as having a conventional film screen mammogram.


 Uses of a mammography

Mammograms are used for two purposes: exploratory, to detect early breast cancer in women experiencing no symptoms, and diagnostic to detect and diagnose breast disease in women experiencing symptoms such as lumps, pain or nipple discharge.

  • Exploratory mammography: it is the early detection of breast cancer for it can show changes in the breast up to two years before they are found by the physician or the patient. It is advisable to undergo an exploratory mammography every year for women, starting from age 40. Research has shown that an annual examination leads to an early detection of breast cancer, and it is a stage in which there are more possibilities of cure and there are more breast preservation therapies available.
  • Diagnostic mammography: Diagnostic mammography is used to assess a patient with abnormal clinical findings—such as breast nodes and lumps—detected by the woman or the physician. Diagnostic mammography may also be done after an abnormal screening mammography in order to evaluate the area of concern on the screening exam.

These examinations may save your life, if you have any concern consult your physician.

Previous preparation

Before scheduling a mammogram, you should discuss any new findings or problems in your breasts with your doctor. In addition, inform your doctor of any prior surgeries, hormone use, and family or personal history of breast cancer.

Here is some advice for your examination:

  • The best time to perform a mammogram is one week after your period.
  • Always inform your doctor or x-ray technologist if there is any possibility that you are pregnant.
  • Do not wear deodorant, talcum powder or lotion under your arms or on your breasts on the day of the exam. These can appear on the mammogram as calcium spots.
  • Describe any breast symptoms or problems to the technologist performing the exam.
  • If possible, obtain prior mammograms and make them available to the radiologist at the time of the current exam.
  • Ask when your results will be available; do not assume the results are normal if you do not hear from your doctor or the mammography facility.

 How is a mammography performed?

Mammography is performed on an outpatient basis.

During mammography, a specially qualified radiologic technologist will position your breast in the mammography unit. Your breast will be placed on a special platform and compressed with a paddle (often made of clear Plexiglas or other plastic). The technologist will gradually compress your breast.

With a mammography, some women may experience discomfort, however, in Medica Sur we want you to feel confident and in a comfortable environment, therefore we guide you the process of your study:


  • You sit down comfortably in the chair of the device (mammography unit) or if you may remain standing, depending on how you feel better.
  • The person who will be with you during this process, in this case the technologist, will place the breast on the scanner.
  • The device will start the compression of the breast electronically to reduce the volume and obtain an optimal image with a low dose of radiation.
  • You must hold very still and may be asked to keep from breathing for a few seconds while the x-ray picture is taken to reduce the possibility of a blurred image.
  • The technologist will walk behind a wall or into the next room to activate the x-ray machine.
  • The image will be displayed almost immediately on the monitor near you.
  • The technologist will perform 4 or 6 similar exposures according to the instructions given by the radiologist.
  • Your physician will check the images and will interview you afterwards.
  • The study takes about 15-20 minutes.
  • Does not require preparation.
  • Results are available in 48 hrs.

You must be certain that this study will be performed with maximum respect and professionalism.

Dual Source Computed Tomography (DSCT)

A dual source computed tomography is the image obtained of a slice or section of an object (for example your body) built by a computer from a series of x-ray images of that section of the object, taken by an x-ray emitter and detector that swirl around the object on an axis.

A DSCT device basically consists of a gantry, where the patient is introduced, an x-ray emitter and detector behind the walls of the gantry, which swirl around the patient, and a computer that analyzes the date received by the detector. It should not be confused with MRI scanners, which are long-tube shaped and can sometimes cause claustrophobia.


Uses of DSCT

The uses of DSCT are various. It allows a precision view of the inside of the body in two and three dimensions, so it is used to diagnose different health problems, some of them are:

  • DSCT, for example, is used to identify brain hemorrhage and tumors, although MRI is more commonly used for these purposes.
  • In the lungs they are used to identify emphysemas, fibrosis and tumors. It is also commonly used to determine the presence of pulmonary embolism (a blood clot in the lungs), as well as for abdominal aortic aneurysms (AAA).
  • In the abdomen, it is used to identify renal stones, appendicitis, pancreatitis, etc.
  • In the limbs it is used to obtain detailed imaging of complex fractures, because it can clearly show even very small bones and surrounding tissue such as muscles and blood vessels.
  • It is one of the best and quickest tools to examine chest, abdomen, and pelvis, for it produces detailed transversal images of all kinds of tissues.
  • It is the preferred method to diagnose the different types of cancer including lung cancer, liver, kidney, and pancreas because the image allows the physician to confirm the presence of a tumor, measure its size, determine its exact location, and the effects it has on surrounding tissues that can be affected.
  • As a guide for biopsies and other procedures such as abscess drainage and minimally invasive treatment of tumors.

When something very specific inside the body needs to be observed (such as the blood vessels of a particular area), an intravenous contrast agent is administered, a substance that absorbs x-rays very well due to its opacity to radiation.

Previous preparation

To undergo a DSCT diagnostic examination it is necessary to follow some recommendations in order to obtain better results:

  • You may be asked not to eat or drink anything for several hours before the study, especially if a contrast agent will be used.
  • If you are allergic to a contrast agent or “dye”, your physician may prescribe some medications to reduce the risk of allergic reactions.
  • You should inform your doctor of any medications you are taking and whether you have any allergies.
  • Tell your doctor about any disease or ailment you have suffered from recently, and whether you have a history of cardiac diseases, asthma, diabetes, renal diseases, or thyroid disorders. Any of these problems may increase the risk of a rare adverse effect.
  • Women should always inform their technologist if there is any possibility that they are pregnant.
  • Metal objects such as jewelry, eyeglasses, dentures, and hairpins may affect CT imaging, therefore they should be left at home or removed before the study.
  • You may be asked to remove hearing aids and dental work. Women will be asked to take of their bra if it has metal wires.
  • Wear loose and comfortable clothes for the examination. You may be provided with a gown to wear during the study.

 How is a Dual Source Computed Tomography performed?

For this study you should not be worried, for in Medica Sur you will have the support and guidance of expert radiologists who will guide you through the process of your scan; for your comfort here are some of the steps to be followed during the study:

  • The technologist starts by placing you on the CT examination table, generally facing up, and not very often on one’s side or facing down.
  • Straps and cushions may be used to help you remain in the position needed and to stay still during the examination. Depending on the part of the body being examined, you may be asked to place your hands on your head.
  • If contrast agents are needed, they will be drunk, or administered through intravenous injection (IV) or by enema depending on the type of exam.
  • After that, the table will move rapidly through the scanning device to determine the right initial position for the exploration. Then, the table will move slowly through the device as it performs the exploration. Depending on the type of CT exploration, the device may run several scans.
  • You may be asked to keep from breathing during the exploration. Any movement derived from breathing or moving the body, may affect the imaging.
  • When the study is completed, you may be asked to wait until the technologist makes sure the imaging have enough good quality for an accurate interpretation.
  • The study takes about 30 minutes. The part of the procedure in which the intravenous contrast is injected usually takes between 10 and 30 seconds.

In general, DSCT studies are quick, simple and painless. With helical DCST the amount of time you have to lie in bed and remain still is reduced.