Commonly used diagnostic imaging tools

Posted by Resident Doctor, Master Tran Duc Tuan - Department of Diagnostic Imaging - Vinmec Central Park International General Hospital

Diagnostic imaging allows doctors to look inside a patient's body for signs of disease. Because each type of machine has a different structure and function to create images of the structures and activities inside the patient's body, the type of imaging equipment the doctor will use depends on the symptoms of the patient. the patient and which parts need to be examined.

X-ray imaging is the most common technique and is performed at medical facilities that are qualified to perform this technique. X-ray, which is also a broad term that includes many different types of X-rays. Patients need this technique for a variety of reasons, including diagnosing the cause of pain, determining the extent of the injury, checking disease progression, and evaluating the effectiveness of treatments.
The part of the body to be photographed will be placed between the X-ray machine and the photographic film or digital X-ray sensor. The patient needs to stay still while the generator sends electromagnetic waves (radiation) through the body, revealing an image that reflects the internal structure of the body. Radiation exposure from X-rays is not harmful, but your doctor will take special precautions if you are pregnant.
In some cases, the patient will have more contrast material injected into the joint during the X-ray, this technique is called a joint X-ray to help the doctor see the soft tissue structures inside the joint or help the doctor locate the needle into the joint to drain fluid or inject medicine into the joint.

Computed tomography (CT scan) allows the doctor to see cross-sections of the body. Cross-sectional images produce more detailed images than conventional X-rays. In fact, a CT scan is often ordered when something suspicious shows up on an X-ray and the doctor needs to find out more.
The patient will lie fixed on the slide and will slide into the CT scanner which is shaped like a cylinder. This process is painless. An X-ray tube slowly rotates around the patient, taking multiple pictures from all directions. The computer combines the captured images to create a two-dimensional view on the computer screen.
You may need a CT scan if you have problems with your small bone structure or if you have a serious injury to your brain, spinal cord, chest, abdomen, or pelvis. Sometimes, the patient may be given a contrast dye to make certain parts of the body show up better on the scan. In addition, a CT scan costs more and takes longer than a conventional X-ray.

Another option for capturing cross-sectional images is MRI. Similar to CT scans, MRIs are effectively used to image soft tissues such as organs and tendons. Unlike a CT scan, an MRI scan does not use ionizing radiation, instead it uses a strong magnetic field and radio waves. Because they don't use radiation, MRIs are generally thought to be safer, but they also take longer to perform. While a CT scan can take as little as five minutes, an MRI can take up to half an hour or longer depending on the procedure.
The patient will lie on a sliding table and slide into the tubular MRI scanner. The MRI machine generates a magnetic field around the patient and then broadcasts radio waves to the area of ​​the body to be examined. A computer is used to record the movement of various parts such as tendons, ligaments, nerves, ... and convert the data into two-dimensional images. The patient will not feel any pain during the MRI scan, but the machine may be noisy.
MRI can be used to help diagnose torn knee ligaments and cartilage, herniated discs, osteosarcomas, osteomas, and other problems. This technique can take anywhere from 30 to 60 minutes.

Mammograms are done to screen for and diagnose breast cancer. Mammography is used to detect breast abnormalities or to check for malignancies after finding a female patient has had a lump or thickening in the breast.

Ultrasound is used to take pictures from inside the body using high-frequency sound waves of soft tissues such as organs and blood vessels. For situations where exposure to radioactive materials is limited, ultrasound is a good choice for screening, for example pregnant women.
Preparation before ultrasound will depend on which part needs ultrasound. For abdominal ultrasound, the patient must fast, but drink water. The patient will lie down on the examination table and the doctor will apply a special gel to the skin and then, use the transducer of the ultrasound machine to send high frequency sound waves into the body as the transducer moves over the skin. . These sound waves create an image of what is happening inside the body and display it on an electronic screen.

Positron emission tomography scan or PET scan detects disease in the body at the cellular level. This technique uses a special type of contrast medium that contains a radioactive tracer. Depending on the procedure, this substance can be introduced into the body in one of three ways: Intravenous injection, inhalation, or oral administration. Some organs and tissues then absorb the tracer. When the PET machine detects these substances, monitoring tools help the doctor see how well the organs and tissues are working. It takes a certain amount of time for the radioactive tracer to move through the body, so a patient may have to wait about an hour before starting the scan. When the time comes, the patient will lie down on the table and automatically push into the O-camera. The technician will instruct the patient when to be immobile and when to hold their breath.
Customers who need to visit and do imaging tests can directly go to Vinmec International General Hospital nationwide, please book an appointment on the website for service.