If you’ve been recommended to get a CT scan of the chest – don’t worry. It’s a painless, non-invasive test, with minimized radiation, that helps the doctor find out what’s troubling you by getting a clear picture of the internal structures of your body. A CT (Computed Tomography) machine uses a combination of X-rays and a computer to take images of the inside of your body. If you’re wondering why you can’t get an MRI scan instead of a CT for your lungs, it’s because CT scans provide better images of air-filled organs like the lungs than MRI scans, enabling radiologists and doctors to study minor differences in lung nodules. Also, CT scans are faster – an important aspect because you may have to hold your breath during a lung scan in order to avoid blurred images due to movement.
How does a CT machine work?
A CT scanner is like a large donut-shaped machine with a table in the middle of the donut-shaped ring. You will be asked to lie on the table, as it moves in and out of the donut ring. This ring then rotates, taking pictures of the body in multiple hi-resolution slices, which enable radiologists and doctors to view sections of your organs/body more clearly. These slices are often compared to the slices of a loaf of bread – where each individual slice can be seen clearly, while being part of the whole.
CT scan and radiation: Throughout the scan, experienced radiologists will be controlling the amount of radiation dose, in order to use the minimum possible radiation required. Especially in the case of children, the radiation dose is continuously monitored and adjusted according to the size of the patient and the scan area. This is why it’s crucial to get your scan done from a reputed center with qualified radiologists.
New technology in CT scan: Advanced CT scanners, like the multi-slice CT machines at Star Imaging, take multiple slices with just one rotation of the donut-shaped ring, making CT scans much faster. This renders the entire scan experience more comfortable, since patients don’t have to lie still on the table for long.
How should you prepare?
- Before going in for a chest/lung scan, you will be asked to remove all clothing from the waist up, and change into a hospital gown
- You will be asked to remove all metallic accessories including jewellery, watches, earrings, chains, etc. – while phones and personal belongings will have to be left outside
- If you need a scan with contrast, which will highlight certain internal parts of the body better, an IV cannula will be inserted into your vein – during the scan, a dye will then be injected through this IV
- Ladies, make sure you inform the doctor if you are pregnant, or think you may be pregnant
- If you’re getting a scan with contrast, you may be asked to not eat or consume solids and liquids for a minimum of four hours before the scan –always ask the scan centre for instructions when you call to set up your appointment
The actual scan
The actual CT scan only takes 10-15 minutes – you will be asked to lie on the table and stay still, as the table slides in and out a few times to check your body position before the scanning process begins. Don’t worry if the nurses use straps to confine your body – this is only to avoid a repeat of the scan, since even slight movements can cause blurred images (artifacts on the scan). Better to have the straps than go through the whole process again. Once the scan begins, you will be alone in the room, however, you will be in constant communication with the staff and technician through the headset provided.
At times, during the scan, you may be asked to hold your breath, lie still, or even raise your hands above your head. Do follow instructions as closely as possible to ensure the best results.
If you’re in pain or are anxious, and find it difficult to lie still, do not hesitate to talk to the doctors and staff – they will provide some medication to help set you at ease.
CT and claustrophobia: Since the CT machine is open on both sides, people do not generally feel claustrophobic. However, if you’re still worried on this score, do talk to the staff, and they’ll find a way to help you.
CT scan time
CT scans are generally quick, the scan may get done in 10-15 minutes, while the pre-preparation takes 20-30 minutes. Post the scan, you may be kept under observation for a few more minutes, and also until the technician checks to see if the images obtained are clear enough. Always remember to ask your centre for a CD of the scan – this will come in handy when your doctor needs to view the images in detail.