CBCT - Cone Beam Computed Tomography is a specialized form of computed tomography (CT) that utilizes a cone-shaped X-ray beam to create detailed 3D images of the body. Unlike traditional CT scanners, which use a fan-shaped beam, CBCT produces a cone-shaped beam that allows for more efficient and accurate imaging of targeted areas. The technology is commonly used in dentistry, orthopedics, and otolaryngology, among other fields.
First off, let's talk about the fact that this machine is essentially a giant donut that you have to lie down inside of. And not just any donut, a medical-grade donut that costs thousands of dollars to manufacture. So, if you ever find yourself inside one of these machines, just know that you're basically a jelly-filled pastry waiting to be imaged.
In short, it is a fancy and advanced medical technology which helps the doctors diagnose way better with 3D images of our body.
The Science
To understand the science behind CBCT, we first should understand the science behind X-rays. X-rays are a form of electromagnetic radiation that have high energy and short wavelengths. When X-rays pass through the body, they are absorbed by different tissues in varying degrees, depending on their density and composition, thus creating a 2D image of the skeletal structure on a film where the X-rays are incident after passing through the body.
CBCT uses an X-ray emitter and a detector array which is composed of numerous sensors that are designed to detect X-rays. The emitter and the detector are placed opposite to each other on a freely movable head which is attached to the stand at the top.
It's more or less similar to X-ray imaging except that it uses a cone-shaped beam whereas the X-ray machine uses a fan-shaped beam. And it rotates around your head to get an image but the X-ray machines don't.
Imaging process
The imaging process involves a few more steps than a conventional X-ray machine. First the patient is positioned on a specialized table, which can be adjusted to capture images from different angles. The CBCT machine then rotates around the patient, capturing multiple images from different perspectives. That's all.
The patient is positioned on a table and the machine starts to spin. As it rotates, it emits X-rays from one end which passes through your head and is captured by the detector arrays on the other end. This emission and detection happens continuously till it covers one complete rotation.
There is a process called Back Projection which involves tracing the path of each X-ray beam as it passes through the body, and then using this information to create a detailed 3D model of the targeted area. Once the images have been captured, the computer uses back projection to reconstruct the 3D image.
How would the result look like?
I cannot find any images for this from the web. But from the words from doctors, what I can understand is that, the result will be something like a component in Blender. You can zoom, pan, rotate and visualize your skull as a 3D object in a 3 dimensional space.
Radiation levels
This CBCT emits no radiation levels. I'm just kidding. Well we're speaking about X-rays so there should be some minimal radiation levels which your body would be exposed to when you take that scan.
According to the American Dental Association, the effective dose of radiation from a dental CBCT scan is typically in the range of 5-600 micro sieverts - (μSv), which is equivalent to one or two days of the amount of natural background radiation you are being exposed daily.
Radiation dose of CBCT is relatively low when compared to conventional X-ray machines. According to the U.S. Food and Drug Administration, the radiation dose from a typical chest X-ray is approximately 100 micro sieverts (μSv), which is equivalent to 10 days of the amount of natural background radiation you are being exposed daily.
To put this natural background radiation into context, an average person receives an annual dose of about 3 milli sieverts (mSv) from natural sources of radiation, such as cosmic radiation and radon gas.
Applications of CBCT
CBCT is used in a wide range of medical and dental applications. In dentistry, it is commonly used to capture detailed images of the teeth and jawbone, which can be used to diagnose and treat conditions such as tooth decay, periodontal disease, and jaw misalignment.
In orthopedics, CBCT is used to capture images of the bones and joints, which can be used to diagnose and treat conditions such as fractures, dislocations, and arthritis. In otolaryngology, it is used to capture images of the sinuses, which can be used to diagnose and treat conditions such as sinusitis and nasal polyps.
Advantages of CBCT
One of the primary advantages of CBCT is its ability to capture detailed 3D images of targeted areas. This allows for more accurate diagnoses and treatments, as doctors and dentists can see the targeted area from multiple angles and in greater detail.
Another advantage of CBCT is its lower radiation dose compared to traditional CT scanners. CBCT uses a cone-shaped beam that is focused on the targeted area, which reduces the amount of radiation exposure to other parts of the body.