Nowadays CT Scan (Computed Tomography) also known as CAT Scan (Computer Assisted Tomography) is an essential part of radiodiagnosis.

It is a unique tool for radiologists to diagnose the patient’s quick and easy way.

More important is that most of the time accept biopsy and other complex diagnostic procedures it is totally painless for patients.

In a simple manner answer to “What can CT Scan detect?” is that it shows the cross-section area of patient’s body organs in the desired thickness without performing any surgical procedure.

The more simple way to understand imagine a cucumber and a knife. If knife cut cucumber from the middle.

Here we get circular pieces with a visible inner cross-section area of cucumber.

Here are the images below for more clarity.

Cucumber slicing example

Similarly CT scan machine also virtually cut a slice of our body organ need to diagnose in any selected plane and show as mentioned below the image.

Image generation of CT Scan after slicing

Here also an option in the ct scan machine for slice thickness selection. In the post (Digital Geometry) processing process arrange all the slices to produce a 3D images of an organ (body part).

3D CT Scan

The Radiologist acquired patient images from machines and compare the standard human anatomy organ structure for any dissimilarities.

Also can find out the location and size of fracture, internal bleed, or cancer for surgery purpose. Thus CT Scan machine is helpful to make diagnoses.

How does a CT Scan work

To practically understand the working need to start from Radon Transform named after Johann Radon.

Radon Transform is a mathematical theory, which is behind all kinds of computed tomography techniques.

Before going further lets quick view about CT Scan vs X-Ray.

CT Scan vs X-Ray

Both machines use X-Ray as a source for generating internal organs images of the given subject.

Even though in CT Scan and X-Ray beam is collimated. But in the CT beam is narrow in size, fan-shaped unlike the wide rectangular beam in X-ray.

A conventional X-ray machine takes a square or rectangular picture of the inside of the human body. On an X-ray film or CR Cassette / DR Detector.

X-Ray Process

The denser objects (like bone) allow less X-Ray to penetrate and appeared white, on the other hand, the less dense objects (like air) pass maximum X-Ray through it and so appeared black.

CT Scan Process

During the X-Ray, the collimator can limit the area of exposure but can not limit the thickness of the object (patient’s body ).

Difference between images of CT Scan vs X-Ray

In the 1960’s Dr. Houndsfield came up with a remarkable new way to use these X-rays with computer-assisted tomography.

Instead of a large area exposure, his idea was to make a thin collimated conical X-Ray beam exposure or series of exposures called a ‘slice’.

Normally CT Scanner can take images of slices thickness 1 to 10 mm’s.

Importantly instead of just making one exposure from one viewpoint, rotates the tube ( X-ray generation source ) around the body and performs many exposures from different viewpoints (angles).

The X-Rays pass through the body collected by the arrays of the receiver called Detector. Which also moves along with the tube but is placed in the opposite direction of the x-ray tube (source).

Most modern CT scanners take 500 to 1000 exposures in 1 revolution around the patient. Each exposure is called a view.

Up to this point, there was nothing that new, lots of scientist worked.

Dr. Houndsfield collects raw data of all views and put them into a computer (what is computer definition) and used the mathematical formulas of ‘convolution’ and ‘back-projection’ to create a cross-sectional image from that data known as a slice.

By taking multiple slices, the human body can be viewed like slices of bread without actually cutting the patient into pieces.

The remarkable images were so revolutionary that Dr. Godfrey Hounsfield received the Nobel Prize for his work jointly with Allan MacLeod Cormack.

Basic working principle of CT Scan

The circle represents the axis positions of the tube and detector as they rotate.

CT Scan raw data collection process

The X-Ray source

This is known as the X-Ray tube. It generates X-Rays that will go through the object or patient’s body. For most scanners, the tube is at 12 o’clock position (apex) when it begins scanning the patient.


This is the part of CT Scanner where the patient or object to be scanned. For a CT scan machine, the reconstructed image is 512 by 512 pixels (points).

CT Scan Gantry


The detector is arrays of receivers that measure the X-Rays that pass through the patient. A typical multi-slice detector has 752 or 912 channels.

As the CT scanner rotates and collects the X-Rays that pass through the patient. After that convert from analog to digital information.

The CT scanner takes 984 views (in most cases and it may vary)of the patient during a 360-degree rotation of the tube and detector.

X-Ray measurement at detector channels

As you can see the X-rays are measured by the detector. Fewer X-rays are getting through the round object. The fewer X-rays there are at the detector.

Denser the objects their less X-Ray at that location. Density attenuates between the X-ray tube and the detector because of the object between them.

Each channel of detector represents the pixels of varying density. The detector can only detect the total amount of radiation at each channel.

The raw data collection process takes the number of X-rays at each detector channel and converts this to a pixel density accordingly.

The fewer the X-rays, the greater the density of the patient or object’s between the tube and detector.

As the tube begins to move, the shadow of the object moves across the face of the detector. This is called Views vs Channels (sinogram)

View vs channels raw data (Sinogram) of ct scan

CT Scanner’s raw data can be viewed as shown above. So that should be able to visualize how Views versus Channels shows all the raw data taken by the CT scanner.

Sinogram is also useful to troubleshoot problems with the data collection and processing section of the scanner.

Image Reconstruction from Raw Data

Here for image construction use the views versus channel data as raw data and try to reconstruct the original image cross-sectional view.

To do so the following process in involved.

Back Projection

Attempt to recreate the original image using raw data the process called ‘Back Projection’. Remember that for each view that we collected (on the previous screen) we calculated a density number for each channel.

Every channel value of view by the view is taken at a time and performs Fourier transform on each view.

In the next step rearrange each view after performing Fourier transform.

Cross Sectional back projection view

The following shows an object’s cross-sectional image, the first back-projection at zero degrees, and the image after the last back projections.

Problem with Back Projection Image

As seen in the above image the blurring is the problem with back projection.

If consider scanning the value of a single channel (pixel) and plot graph of density numbers after back projection.

It must be look like as mentioned below.

Back projection pixel value

Convolution ( Two Dimensional Fourier Transform)

Pixel value after convolution

Subtract the blurring from back projection, by applying a two-dimensional Fourier transform. Thus achieve an actual image of the original data.

For each view, the value of each pixel is subtracted from the adjacent pixels before the back projection. This method is called ‘Convolution’.

The following shows the original image after convolution and back projection. Present on screen as 512 x 512 matrix.

Image after convolution and back projection

This picture is very close to the object’s cross-sectional area. The convolution filters are very difficult to design and perfect.

Different filters work better with hard objects like bone, and others work well with soft objects.

Artifact of CT Scan and Image Quality

Any known or unknown abnormality like the ring, spot, streaks, or missing of information that reduces the quality of information inside the output image is called an Artifact.

Usually, it occurs when some foreign body comes between tube and detector accept object need to scan.

For any engineer troubleshoot an image artifact is a very tedious job.

Some other more frequent reasons are faulty detector channel or data path otherwise calibration.

The calibration method, detector architecture, and data path vary according to the manufacturing company and their models.

Some common artifacts are :

Aliasing Artifacts

There are many types of aliasing artifacts classified by how they look like. The artifact problem may be rise from the source or detector side.

Aliasing Artifacts

Unless getting very few numbers of views and improper grid or filter selection for back projection.

Patient motion Artifacts

The mobilization of the patient causes blurred image as a result.

Motion Artifact

No matter what kind of motion dealing with, the most efficient way to reduce motion artifact is to minimize scanning time.

Although it has been achieved by helical CT, the effort of reducing patient motion artifacts is still making.

Methods to reduce patient motion artifacts include patient immobilization, ECG gated CT and some correction algorithms.

Metal Artifacts or Foreign Body Artifacts

Metallic materials such as prosthetic devices, dental fillings, surgical clips, Contrast residue, and electrodes produce streak artifacts on the image.

There are so many techniques that remove the artifacts from the final image.

Metal Artifact

One of them is metal artifact reduction (MAR) by using threshold values to define metal images and interpolate missing images to reconstruct a new image data.

This method of threshold technique can also be used in reducing artifacts result from arterial wall calcification.

Beam Hardening Artifacts

Beam hardening is a phenomenal result of the increase of the mean energy of the x-ray beam when it passes through an object.

Beam Hardening Artifact

Therefore, the CT numbers (HU) of certain image change and produce some artifacts.

The artifact can be minimized or removed by applying a filter that ensures the uniformity of the beam at the detectors.

Partial Volume Artifacts

Partial volume artifacts arise when a voxel contains many types of tissue.

It will produce a CT number as an average value of all types of tissue.

This is the source of partial volume effect and will appear as bands and streaks.

Partial Volume Artifact with Ring

The posterior cranial fossa is the most critical region to produce a partial volume artifact.

Using thinner slice and some computer algorithms can reduce partial volume artifacts.

Ring Artifacts

When one or more than one concentric ring or band in the color of black or white appears inside the image called ring artifacts.


Most of the time appears due to a change in the ct value of air in the calibration data and the value during the scan taken.

Otherwise, an artifact is due to obstacles on the detector channel or the channel is faulty itself.

Streak Artifacts

The most common reason for this artifact is missing view during the image acquisition process.

Missing views due to intermittent fluctuations in the X-Ray generation or data acquisition system (DAS) power supply.

In this case, all streaks pass through the common center. But the below image is a classic example of a streak artifact across the circle due to raw data storage ram fault.

Streak Artifact with Circle

History and Generations of CT Scan

Even X-Ray was discovered by Wilhelm Rontgen in 1895 but till 1971 CT Scan could not be made. Because the technology and computers evolved later on.

In real development only started after 1917 when Johann Radon present his Radon Transform Theorem.

Based on Radon, theorem scientists start experimenting on tomography in different ways.

Like in the year 1959 the Ronald N. Bracewell used a method similar to Ronald Transform to reconstruct the map of solar radiation.

From here the William Oldendorf grab the idea for the human body, head scan.

In the year 1961 published paper was the foundation for developing mathematics for computed tomography by Allan MacLeod Cormack.

Dr. Godfrey Hounsfield at EMI (Electric and Musical Industries Ltd.) and Allan MacLeod Cormack in tufts university developed head CT Scanner using Allan’s mathematics.

Later Pfizer the drug company take rights from the university and produce a 200FS model which was fast, with no need for a water tank, and uses a 256 x 256 matrix instead of an 80 x 80 matrix.

Generations of CT Scan

Classification of CT Scan according to their geometrical architecture categorized in seven generations and evolution is continuing.

First Generation CT Scan

It was the simplest possible scanner using one pencil beam ( pinhole ) x-ray source, two detectors, rotate, and translate mechanism only.

Most of the things explain earlier which is belongs to the first generation. Due to again repetition explaining in short.

Second Generation CT Scan

For reducing scan time introduce thirtieth (30) detectors also to cover all the x-ray on detectors channels.

Changed x-ray source pinhole to narrow fan beam source up to 10 degrees.

Rotate and translate mechanism was as before. But still capable to perform only head scans.

Here CT scanner not fast enough to acquire other movable body part images.

Third Generation CT Scan

Again the meager change in the third generation was made to minimize the scan time to under twenty seconds.

For this reason, made wide arch size detector with 400 to 1000 channels and keep wide fan beam angle 40 to 60 degree to cover all the channels of the detector.

Also, remove translation movement and thus also speed increased. From the third generation, a body scan becomes possible on the CT Scanner machine.

Rotation servo mechanism keep unchanged.

Fourth Generation CT Scan

In the fourth generation, CT Scanners try to overcome ring artifacts which were big issues in the third generation because of the large no of channels (more than 400) used in detectors.

Here are arranged detector channels ( 5000 approx) around 360 degrees in a fixed position. The only tube rotates with a wide beam angle.

Therefore this system is called rotate-stationary geometry at that time. Because of this kind of arrangement (stable detector) no need to calibrate the detector so often.

Fifth Generation CT Scan

Exclusively dedicated to cardiac CT imaging even cine-CT name for it. Even achieve 50 mili seconds acquisition time through electron beam CT Scanners.

Electron beam CT Scanner

Similar to the fourth generation detectors channel make x-ray source also stationary.

For that, the half-circle tungsten ring is put around the patient’s body and the rest half is for detector channels.

Tungsten ring works as an anode which is an integral part of an X-Ray tube.

When an electron beam strike to tungsten ring anode generates an X-Ray which is received by detectors through the patient’s body.

No doubt there is a deflection mechanism to move electron beam across the tungsten ring.

This arrangement called a stationary-stationary arrangement.

Those CT Scanners was not so much popular because of its prize was very high and the limited use for cardiologists.

Sixth Generation CT Scan

Earlier generations of rotating mechanism use servo mechanism which rotates in one direction then stop.

The next axial scan rotates in opposite direction for acquiring the next image.

The main issue with this process (start- accelerate-rotate-apply break and de-accelerate-stop.

Again the same process in opposite direction) was time taken to process, can not operate detector, and X-ray tube for a long time.


Problem resolved when slip-ring is introduced and now power and signals can be interchanged with the fast rotating parts assembly.

Because of slip-ring technology now detector and Tube can rotate very fast in one direction.

Also no need to turn it off in between so that axial image acquire can be fast and continuous.

Spiral Scan

Now the machines were able to take axial or helical scans but helical scans don’t have full axial data.

which is compensated by changes in reconstruction methods. Those models were very famous as Spiral CT Scanners.

Seventh Generation CT Scan

Instead of changing in rotation mechanism, increase the detector (channels) in parallel so that during one rotation can acquire more than one image.

This way can cover more body areas in a short time.

Multi Slice CT Scan Detector

Dual slice, four-slice, eight slices, and up to more than a thousand slices can be acquired in a single rotation.

To achieve this increase detector thickness to put more elements in parallel and make the cone-beam collimator wider in the z-direction.

Also, make changes in algorithm and software programs.

Only a solid-state detector makes it possible to design detector elements small and arrange them in a parallel fashion.

Earlier CT Scan machines uses Xenon detectors.

Dual Source CT Scan

Again the dual-source technology introduce for making cardiac diagnosis like coronary artery disease (CAD) and Coronary Computed Tomography Angiography (CTA)

The rest of the machine is similar to previous generations except using two different X-Ray sources with different energy and angle.

It is done by so many methods which seem suitable for the company.

Someone is using two x-ray tubes and another company using one tube as dual-source making changes inside the tube.

Currently this is the second generation of dual source CT Scanners.

ASIR (Adaptive Statistical Iterative Reconstruction)

The main reason for the development and using ASIR to reduce the dose of radiation.

During scan about 60% without compromise with the image quality. This is applied after the images are reconstructed.

Basically, ASIR uses Harr Transform to reduce noise from an image. 2D ASIR is applied within each slice, and 3D is performed from slice to slice.

The Harr transform is actually an image compression algorithm. Firstly applied in digital photography.

Where diffusion filter is applied to areas of the image. It was developed for digital photography image processing.

After filtering, a single area might appear slightly lighter or darker than the surrounding areas.

IN the CT Scanner views are collected and used to create 2 images. The even views are back-projected to create one image and the odd views are back-projected to create a second image.

Both images are subtracted to create a third different image.
The SD of the center pixels is calculated.

This number represents the amount of noise in the images.

The noise value is used for the constants in the diffusion filter in the next steps as constant.

The anisotropic diffusion filter basically works by “averaging” noise across adjacent pixels.

The number of repetitions is based on the percentage of noise the operator selects to remove.

This is the “iterative” part. The filter is applied to the final image.

The “averaging” is a convolution like a filter. The constants for the width of the filter come from the “noise map” generation from the first flowchart.

It appears we are doing this over several pixels in each direction.

This filter is applied in 2 dimensions (left/right and Up/down) or 3 dimensions (between adjacent images), so it is more processing-intensive than standard convolution.

The diffusion filter also has edge detection. If the next pixel over is significantly different, it will stop. This keeps the edges sharp.

CT Scan machine Main Units (Parts)

Almost every CT Scan machine consists of four basic units (Gantry, Table, Console, and PDU) and other accessories. Setup required a minimum of two separate rooms.

One known as the gantry room where patient lie-down on the table for scanning.

Another one called the console room from where the radiographer or radiologist performs an examination.

Between both rooms keep one big lead glass window for visually patient monitoring and avoid radiation inside the console from the gantry room.

Gantry Table Room

Table and Gantry

Gantry and table integrated and align such a way so that while patients lie down on the table.

The patient is positioned by adjusting table height so that cradle ( moving part of the table moves the patient in and out through gantry bore) could be the position for required body part scanning.

Inside the gantry all image (raw data) acquiring devices like X-ray Tube, DAS / Detector, Slip Ring, Servo Mechanism for moving assembly, Tilt Mechanism, etc.

PDU (Power Distribution Unit)

As clear by name all the power comes from mains first fed into power distribution unit.

Here generate all the required power supply for the rest of the units and make it possible to control all the power input for a machine.

That can be controlled from the gantry, table, and console as and when required by units.


In case of any miss-happening emergency, button pressed then PDU shutdown the rotation, X-Ray generator power, and make cradle-free to patient pull out with hands.


The console visualizes, configure and control from console room up-to patient registration to the end of the examination.

It is the place where radiation dose, scan technique, scan time, filter, table movement, and other parameters configured.

At the end console process raw data and produce the desired result on the console monitor.

CT Scanner Console

Even console can process patient data in many ways (2-D,3-D, Visualize image from different planes and angles ) so that radiologists can diagnose accurately.

Other units of CT Scan works under the console as master-slave fashion.

Many companies used Hp z800 workstation ( hp z800 specs ) as a main part of the console unit.


Other small parts like headrest, armrest, and lots of such things need when CT Scan was done on the specific part of the body.

Few more accessories come along with a CT Scan machine for technical (service and troubleshooting) purpose like a phantom set for calibration, toolbox, etc.

Other Accessories

Those are not standard parts or come along with the CT Scan machine. These are the options for smoothly making diagnoses.

Pressure Injector

Used to inject contrast (die) remotely from the console. With the help of injectors, radiographers can control the amount and timing of contrast.

MedRad Contrast Injector

Modern machines where need to scan immediately before contrast flow out prefer injectors instead of manual.

ECG or EKG Monitor

Captured ECG pulses show directly on the console screen to assist in proper Coronary Artery Imaging.


Respiratory system

Similar to ECG, display lung/chest moments on console monitor for breast, chest scan, or lung scan. Mostly used in IGRT for therapy planning.

Respiratory System


The uninterrupted power supply is used for those places where the normal power supply is not good.

To protect from damage of machine due to all of the sudden power shutdown.

UPS for Console

During diagnosis power shutdown is also very critical.


Used when the quality of normal line power is not good means change in power frequency and voltage fluctuations.


So many countries where power conditions are not good to feed power supply into PDU via Stabilizer.


Mainly used for post-processing of acquired images. Images from the CT Scan machine send to a workstation via the Dicom network.


Here can apply different reconstruction techniques like MPR, MIP, 3-D volumetric or surface view, planer sections, different filters, etc.

Provides the best and clear view of the area where the problem accrues in the body.

Printer or Camera

When a diagnosis is finished on a CT Scan machine and patient or doctor needs reports and images for further treatment or consulting.

Printer (previously called camera) print acquired images on film for this purpose.

Haunsfield Unit (HU) or CT Value

Dr. Godfrey Hounsfield not only invents the CT Scan machine but also introduce a dimensionless unit called CT Value or HU ( Hounsfield Unit).

CT value denotes the density of the selected region (ROI) in the image. Witch means ct value shows the density of scanned objects by calculating its pixel values.

On the zero degrees centigrade and one atmospheric pressure the ct value of pure water is 0 (zero) and for air is -1000.

The ct value for bone is +1000 thus more dense objects have higher HU (CT Value).

It is useful to confirm a diagnosis when need to identify internal bleeding, calcification, cancel tissue/cell identification.

Contrast or CT Scan Dye

When in the scanned images have less observable details and need a more enhanced image for confirming a diagnosis.

Such a point use die or contrast which is a chemical that has the ability to absorb X-ray radiation.

This way the organ needs to diagnose seems more clear in the CT Scan.

During the patient examination contrast absorbed by particular organs and after that it flows out.

For different body parts, there are different ways to give contrast to patients. Oral, Anal and directly inject veins are common practice.

There are mainly two types of contrast Ionic contrast and Non-Ionic contrast.

CT Scan With Contrast

During the normal scan procedure not able to get desired details of that particular region (organ) or need more enhanced images to confirm the diagnosis.

In such a situation perform the CT Scan procedure again with contrast and compare images whether something is missing or now appearing clear after contrast.

CT Scan Without Contrast

As explained above if the CT Scan procedure does no required contrast for further examination. Then no need to pay extra for contrast for CT Scan.

Can a CT Scan Detect Cancer

Big yes because initially CT Scan and MRI are the only way to cross-examine brain tumors or other cancer tissues inside the body after symptoms appear.

Then for confirmation CT guided biopsy also performed and pick some tissues for lab tests. PET is also an important tool for cancer diagnosis and treatment.

Secondly helpful for planning surgery like size, location removing brain tumor inside out.

After the treatment to know how effective the treatment is again CT Scan comes back in the picture.

IGRT (Image-guided Radiation Therapy)

Specially made CT Scan machine models are used for RT Planning.

The purpose of Image-guided radiation therapy is to minimize and precisely the doge of radiotherapy radiation.

Usually, CT Scan used for IGRT have a big size bore between the gantry compare to the normal ct scan machine.

Table cradle also flat instead of curve made from carbon fiber.

Additional attachment lap laser and respiratory system with marker tracking install to position and mark body more precisely.

With the help of these simulate the focused radiation dose and direction, for radiotherapy machine-like linear accelerator.

Especially for moving body parts ( lung, Breast). Also, help to make masks for this purpose.

Type of CT Scan Imaging Examination

CT Scan Imaging now capable of a full-body scan but it is not a common practice.

In general, scan only perform on a particular body part advised by the doctor for scanning.

Like medical terminology for human anatomy CT Scan examination also have the same name.

Use the same name for the upper limb, lower limb, and other extremities organs.

Brain or Head

Very common examination specially in trauma (accidental ) cases.

In the accidental cases when a patient is not conscious and needs to know the damage inside the head ( fracture, bleed, etc.) for starting treatment as soon as possible.

Instead of MRI the CT Scan prefer in trauma cases because it takes less time than Magnetic Resonance Imaging.

Secondly, the reason is the patient may have a magnetic implant inside the body.

The Head study is also used for a brain tumor, calcification, or observe the normal development of the brain, anatomical displacement, swelling.


This study diagnoses the body part between head and shoulder like the ear, nose, mouth, and neck.

Also, perform for facial abnormality ( lump or mass in the neck). Also study thyroid gland abnormality, sinus.


Mainly studied for bone structure and find out the abnormality. Fracture and recovery follow-ups.

Chest or Lungs

Study enlarged lymph nodes, tuberculosis, mycobacterium tuberculosis, lung cancer.


Most of the time scan for slip disk, disk compression, dislocation of L3, L4, L5 or else, spine canal or fracture study.

Cardiac or Angiography

Both studied are different but are related to the heart. Diagnose the heart and its veins and arteries. Study about heart valve and chamber functioning.

Angiography is mainly related to vein and arteries blockages findings. Calcium ct scan also part of angiography.

CT Guided Biopsy

The tissue or small piece of organ collection with the help of a needle for testing in Lab for further treatment without performing open surgery called a biopsy.

CT Scan performs and acquires images in real-time for guiding needle up to the lesion with extreme precaution safest and smallest way.

Abdominal, Lower Abdominal and Pelvic

The liver, spleen, kidney stone, pancreas, adrenal glands, large intestine, gallbladder, intestine, and the gastrointestinal tract comes under these studies.

All the studies usually reefers when patient-reported pain. Then refer him to CT Scan, in case deep study needed then ultrasound study advised.

These studies are often ordered to check for a cause of pain and sometimes to follow up on an abnormality seen on another test such as an ultrasound.

Other Extremities

Legs, knee joints, ankle, hand, palm, and remaining body parts come under the above headline.

Risk and Side Effects

Of course, CT Scan uses X-Ray Tube as a radiation source. Which is Ionic radiation, in other words, ionic radiation removes electrons from the atom.

Simply it destroys our DNA structure and it may cause cancer. Other symptoms are lack of hair, less apatite, rashes, vomit, skin related problems, etc.

How Much Radiation In a CT Scan

Due to the above reasons, CT Scan radiation dose depends on patient body weight and the scanning region.

The maximum dose from CT Scan is 80 mGy in exceptional cases.

For the common study, the doses are around 0.01 to 0.15mGy. Here gray or mGy and sievert or mSv are the units to measure radiation.

In general, the radiation dose from CT Scan is very nominal and comparable with the natural sources of radiation the human body absorbs.

As per the above statement, the study shows there are very rare chances anyone gets side effects because of only a single CT Scan.

Even for extra precaution pregnant ladies never allow scanning due to the risk of radiation exposure to the unborn babies.

CT Scan Dye Side Effects

Contrast is Iodine-based Dye to acquire more enhanced images. In general contrast especially non-ionic contrast never show any kind of reaction and flow out from the body within 24 hours.

In some cases shows rashes or itching like allergy symptoms. Very rare case to see any serious side effects.

Although if women are feeding to a baby then not advise contrast otherwise feed again after 24 hours.

Other CT Scan Applications

The major and most common use of CT Scan machines in the medical/healthcare sector.

But still a few more places where the need to see objects from inside without damaging CT Scan is a useful tool.


There are so many artifacts that need to visualize from the inside but we can not afford to open or damage them from inside.

Very clear example is mummy, found inside the tomb and need to find out information about facial and bone structures, provide valuable information about mummy.

Industrial Applications of CT Scan

So many industries uses CT Scan to check and verify their product quality from inside finished goods for their flaw detection, failure analysis, metrology, assembly analysis.

Also CT Scan used for reverse engineering without damaging the original artifacts.

Forum for CT Scan Error

For any technical or troubleshooting related quarries have forum CT Scanner where can discuss error codes and also can upload screen shot of error.

Here is the article about X Ray, “X Ray Radiology Complete Amazing 101” hope like to read also.

What can CT Scan Detect?

CT Scan can not detect anything, only acquire a cross-sectional view of the body and represent after processing in 2-D or 3-D planes.
But definitely, it helps radiologists to make diagnoses. CT Scan has many tools and filters for enhancement like HU or ct value which makes it easy to reach any conclusion for a radiologist.

What is difference between CT Scan and MRI ?

Few key differences that need to discuss here are
1) CT Scan and MRI both are based on different technologies like CT Scan uses X-Ray for image creation but MRI is based on magnetic resonance imaging which deals with electromagnetic waves.
2) CT Scan is good for hard tissues and objects like bone but on other hand, MRI is good for the study of soft tissues like gray matter.
3) As compare to MRI is really quick nowadays normal brain study can be done in just 20 seconds where MRI takes few minutes to an hour. This is the reason CT scan is very useful like emergency conditions where need quick diagnose.

How long does a CT Scan take?

Nowadays on modern CT Scan, any study can be done in 20 seconds to few minutes until some extraordinary investigation needed to be done.

Why is CT Scan done?

CT Scan needed to see inside our body without surgery for confirming and investigation of abnormality inside the body.

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