Radiology: How do doctors see inside us?

Radiology: How do doctors see inside us?

A trip to the hospital usually means that you are going to have your body checked out. Sometimes, that includes more than just sticking your tongue out and letting the doctor check your breathing. I wanted to know more about these complex machines that are used during our medical checks, and Sengkang Health opened their doors at Alexandra Hospital for me to get a peek into how doctors see inside us.

1. CT Scan: Do not move while inside

CT Scanner / Photo Credit: Ong Kah Jing

CT Scanner / Photo Credit: Ong Kah Jing

An X-ray Computed Tomography Scan (CT scan) utilises radiation to acquire huge chunks of data from the human body and create images out of it for doctors to take a look inside. It is basically a more powerful method of X-ray that takes thousands of vertical X-ray images that can then be “scrolled through” and seen from multiple angles on a computer screen.

A single scanning session takes anywhere from 15 to 40 seconds, depending on the model of the scanner, the portion that is needed for scanning and the body dimensions of the patient. It is a good thing that it is quite short, because much like how we scan documents in the office, the subject should never move during the process.

We had a case where we were scanning the neck and head of a patient and the patient could not resist the urge to sneeze. We were focusing on the arteries and the image produced was blur, so we had to do another take.

Of course, before coming to that decision, we would first see if our objective was met because we do not want our patient go through scans such as this unnecessarily.

- Ng Jiajun, Senior Radiographer, Sengkang Health

The latter part of the CT radiographer’s explanation is referred to as the ALARA principle (also known as, “As Low As Reasonably Achievable”). Without a doubt, a single CT Scan session will expose a patient to a lot more radiation than a single X-Ray session, but proper steps are in order to ensure that CT scans are only recommended to the patient after it is certain that it is necessary in solving the health issues. The benefit of the scan must outweigh the potential harmful effects of it.

MEXT Chart / Photo Credit: Keio University

MEXT Chart / Photo Credit: Keio University

2. Ultrasound: It is more complicated than it looks

Ultrasound Image / Photo Credit: Ong Kah Jing

Ultrasound Image / Photo Credit: Ong Kah Jing

From one huge machine to one that is portable by comparison, the Ultrasound device is something many of us might be familiar with. While it seems simple to operate compared to the other fancy gadgets around the hospital, do not let its small size fool you. There is much skill involved in calibrating the ultrasound to see inside one’s body

Utilising sound instead of light, operating the Ultrasound machine is like taking a photograph with a DSLR camera due to the dozens of knobs and settings to adjust in order to get the perfect image. Humorously known as knob-ology by the internal staff, the operator fine-tunes the settings in order to peek into one’s body with clarity and identify anything that could seem out-of-place. For instance, the operator could increase the frequency of the sound, providing better clarity of the real-time image. But this would mean that the machine’s penetration level is lower and is therefore not applicable in all situations, such as looking at a foetus.

Ultrasound Image / Photo Credit: Ong Kah Jing

Ultrasound Image / Photo Credit: Ong Kah Jing

What’s more – an ultrasound operator has to do all these in real-time. This is unlike the previous mentioned CT scan, in which settings are adjusted and the process is pretty much automated after that. This is then followed by a process of observing any anomalies. By contrast, an ultrasound operator has to do all these tasks simultaneously. Observing such anomalies are also not easy in real time. The image is live and everything is in greyscale, thus requiring ultrasound operators to have sharp observations skills to find what the doctor is looking for.

3. Interventional Radiology: Tickles you from the inside

Catheter / Photo Credit: Ong Kah Jing

Catheter / Photo Credit: Ong Kah Jing

Both the CT scan and ultrasound machines help doctors assess the patient by scanning them from the outside. On the other hand, Interventional Radiology literally goes inside your body. By poking a small hole in the patient’s artery, the doctor will then insert a thin flexible tube known as a catheter and travel through it to reach the desired area. This tube is then used to pump a contrast medium that will then make it easier for doctors to spot anything of interest via x-ray, such as a leaking artery.

Surprisingly, the path to the brain starts from the groin area. The 100cm long tube will journey through the body, with some patients experience a ticklish sensation during the process. All things considered, Interventional Radiology is a massive step up from the previous option of resorting to big surgeries to literally cutting the skin to see what’s inside. The less invasive Interventional Radiology achieves the same objectives with far less complications.

Bone Mineral Density Machine / Photo Credit: Ong Kah Jing

Bone Mineral Density Machine / Photo Credit: Ong Kah Jing

BONUS: Bone Mineral Density Machine

Not only checks your bone’s strength, but also your fat content.

Before concluding the tour, I got to check out the Bone Mineral Density (BMD) Machine. It is a special X-ray machine used to assess the health of the patient’s bone by detecting the minerals present as well as its density. This is then provided as a set of data for the doctor to use for the patient’s assessment

A very simple examination that takes about 10 minutes, the machine usually scans the spine or hip area, the latter being a very good indicator of bone fragility due it being a vulnerable area of fractures and other tell-tale signs for the doctor’s assessment.. Most patients being assessed by the BMD Machine suffer from osteoporosis and other similar conditions involving weak bone strength.

Don’t think that this will apply to you? Think again. It seems some of our daily habits do put us in risk of osteoporosis. One habit highlighted to me by the radiographer was our intake of caffeine! Caffeine in coffee, tea and some soft drinks may decrease calcium absorption. Smoking and alcohol are other negative habits that could lead to osteoporosis.

As technology advances, many diagnosis procedures which are unheard of a few years ago now becomes a daily procedure to help our healthcare professional to diagnose any possible abnormalities quickly and with minimal risks involved. Diagnostics radiology is a good example of how technology advances help improve patient cares as well as providing a team-based care for patients.


This series is made possible through our collaboration with Sengkang Health, a SingHealth institution that aims to build a community compact for a healthier Northeast. We have worked with the doctors of Sengkang Health in creating this health series. Let us know if you want to see more similar content in the comment section below and check out the other articles of this 6-part series.