Guide to CT Scanners

CT scanners are a popular modality and they come in many sizes, number of slices, accessories, and price ranges.

So how to pick a model – Each chapter of this guide covers an important factor that will bring you closer to a great fit.

Main Differences of MRI and CT Scanners 

CT scanners are often compared to MRI scanners. Therefore, before you start choosing a CT scanner, consider checking that you actually need a CT rather than an MRI.

Generally, CT scanners are more suitable for imaging bones and blood vessels.
On the other hand, MRIs are great at detecting very small changes in soft tissue, joints, ligaments, tendons, the spine, and brain.

You would use a CT to:

  • Find and diagnose injuries from trauma
  • Determine the location and size of a tumor
  • Determine cancer stages
  • Diagnose infections
  • Detect the location of blood clots
  • Diagnose conditions of the lungs and heart
  • Identify vague abdominal problems

You would use an MRI to:

  • Diagnose tendon and ligament injury
  • Detect and evaluate spinal cord issues
  • Evaluate soft tissue in more detail
  • Monitor brain tumours
  • Examine complicated abdominal abnormalities

Frequently, CT and MRI are used to image the same body area, however, each can provide different types of information about the region of interest.

Bone imaging is a good example – To examine bones, you typically use a regular X-ray for 2D images or a CT scanner for 3D bone imaging. However, when examining bone marrow, MRI scanners will be the best at detecting abnormalities. This is due to their fat and water seperation ability.

And in some cases, doctors may recommend an MRI scan if the CT scan is unable to provide all the necessary information. For example, in some cancers MRI may better show how deep the tumor has grown into body tissues.

Another difference between CT and MRI scanner is the examination speed.

A CT exam is faster, about 5 to 20 minutes, compared to 15 minutes to 2 hours for MRI examinations.
On top of this, MRI machines are noisy and their tube can be claustrophobic, which is why patients generally find them uncomfortable.

We this cleared up what the main differences between MRI and CT scan machines are.

Main Factors When Choosing a Brand of CT Scanner

The main brands are Toshiba (now Canon Medical), Siemens, GE, and Philips.

All these brands have been supplying high quality CT scanners for years and the value of their used systems is high. Furthermore, it is easy to get your hands on parts from these brands.

Each of the brands has CT scanners installed worldwide, but some regions have a stronger presence of one OEM.
Therefore, the main factor in choosing between the brands, is simply what service providers you have good access to.

On top of this, you might have a strong personal preference, so remember to let the seller know if this is the case, or if you are used to working with a specific brand.

Some of the most common CT scanner series on the secondary market are:

  • Toshiba: Aquilion and Activion
  • Siemens: Somatom Emotion, Sensation, and Definition
  • GE: BrightSpeed, Discovery, LightSpeed, and Optima
  • Philips: Ingenuity and Brilliance

CT Scanner Slices – What Slice Count Do I Need

This is a specification that comes up early in discussions of CT scanner purchases.

In the second-hand market, the commonly available slice counts include 16, 32, 40, 64, and 128 slices.
And more and more we also see 256 and 320-slice CT scanners.

Systems with 4 and 8 slices are still found in the market but are in the process of being withdrawn.

The main effect of the slice count is on the time it takes to perform a CT scan.
The pros of a CT scanner with a higher number of slices are:

  • Reduced scan times
  • Higher patient throughput
  • Lower radiation doses
  • More detailed images with fewer artefacts
  • Options for advanced imaging, such as cardiac exams

Nevertheless, higher number of slices also means higher price. And if you only perform routine studies, the extra cost is likely not worth it – For many clinical facilities, a lower slice count with lower cost will be the soundest investment.

Therefore, when deciding on a CT slice count make sure to balance your clinical needs, your patient flow targets, and your budget.

Lets us look in detail at the individual slice counts, from 4 to 320 slices.

4- and 8-slice CT Scanners

4- or 8-slice CT scanners are a good choice if you run a veterinarian clinic, or a department with a limited number of patients no need for fast diagnosis.

These scanners are among the cheapest on the market, but also perform scans slower. Furthermore, they are less powerful.

They are suitable for follow-up procedures where time is not a factor.

16-slice CT Scanners

The 16- slice is the first choice of many clinics and radiology departments where patient flow is rather steady, as they are faster than the 4- or 8-slice scanners.

These units are great for standard general studies.

That makes the 16-slice suitable for urgent care centers and ERs – but also for busier imaging facilities, as a 16-slice scanner is a solid workhorse.

32-and 40-slice CT Scanners

CT scanners with 32 and 40 slices are typically found in similar situations and facilities as the 16 slice.

The difference is that the extra slices provides more coverage per gantry rotation, and thus further reduce the scan time compared to the 16-slice.

Therefore, the obtained image is not influenced by motion artifacts to the same extent.

Naturally, the price of a CT scanner with 32 or 40 slices will, naturally be a bit higher than for those with a lower number of slices.

64-slice CT Scanners

The 64-slice CT is standard for hospitals and imaging centres.

Thanks to the reduced scan times, more advanced studies, such as cardiac, can be performed.

Its speed and accuracy makes it suitable for practices with moderate to high patient throughput.

In terms of cardiology, a 64-slice CT scanner can perform cardiac examinations but still require slowing of the heart rate. However, for advanced cardiac it is optimal with more slices.

+128-slice CT Scanners

The top-notch scanners, ranging from 128 to 320 slices, can provide whole body scans in seconds, while providing an incredibly sharp 3D image of any organ.

The capabilities of these scanners are often excessive in a standard clinical setting.

Therefore, they are usually found supporting specialty practices, such as cardiac departments, in research facilities, or where the volume of patients is very high.

To sum up, how many slices do you need based on the exams you perform?

As CT scanners are used for many different examinations, knowing the examinations your system will be used for will help you determine what CT scanner is the best for you.

All CT scanners can perform general imaging procedures, for example abdominal, which includes the scanning of internal organs such as liver and kidneys.

However, certain procedures, such as cardiac, rely on higher slice counts to deliver sufficient image quality.

To get a better overview of CT scanner applications in relation to slices, see the table below:

How Much Does a CT Scanner Cost

The price of used CT scanners varies greatly.

It and even though number of slices is the main factor, there are several others that has influence, such as age, demand, model, tube count, and more.

The cost of CT machines on the used market ranges from 35.000 to more than 250.000 euros. Get an overview in the table below.

Keep in mind the several other factors influencing the price of a CT scanner:

  • Brand
  • Age
  • CT X-ray tube and its tube count
  • Injector
  • Workstation
  • Warranty and installation

If you want to dive deeper into the costs of used CT scanners and the factors affecting the prices, you can read our dedicated blog post on that matter.

Or watch our video explaining CT scanner pricing:

CT Scanner Tube and Tube Count

An X-ray tube is a crucial part of a CT scanner.

Furthermore, replacing a tube can be costly, a new X-ray tube can cost from 50.000 to 150.000 euro. Therefore, a system will be cheaper with a more heavily used tube, but it also comes with a bit more risk of an impending cost.

A newer tube comes with less risk, but of course also at a higher price. Therefore, choice of tube condition depends on personal preference and budget.

Tube condition is assessed through tube count, for which there are multiple measures, depending on the manufacturer:

  • Total patient exams
  • Clicks/counts
  • Scan seconds
  • mAs (milliampere seconds)

Learn more about each in a dedicated blog post – 4 Measures of X-ray Tube Count on CT Scanners.

X-ray tubes are defined by the amount of heat they can withstand, measured in an MHU (Mega Heat Unit).
The larger the number (MHU), the more heat the tube can take and the more exams it can perform.

MHU can assist you in estimating how long a CT scanner tube will last. For example, a 7MHU tube can last more than 150 million mAs, while a 4 MHU tube lasts approx. 70-100 million mAs. These are average figures and may vary depending on the manufacturer.

Tip for extending the life of your CT tube:

Before you begin your CT scan schedule, make sure to perform a tube warm-up.
This will raise the temperature in the tube gradually and prevent damage due to temperature shock.

Air Cooled vs Water Cooled CT Scanners

Another factor to consider when choosing a CT scanner is its accompanying cooling system.

There are many moving parts inside, and thus, the the CT machine quickly generates heat.

The systems are generally designed to handle approximately 100 kW of power in the tube and a high patient load. Therefore, their cooling system is important to ensure that the system is running optimally.

There are two types of cooling systems used in CT scanners.

The most widely used is air cooling, but you can also get water cooled models, mainly from Siemens and Philips, such as the Siemens Sensation line.

Air cooled CT scanners

Air cooled systems dissipates heat to the surrounding air through the outer covers of the gantry by a fan.

This is the cooling system on most available CT scanners.

The cooler itself is a bit more expensive and air cooled systems are hereby slightly more expensive than the water cooled ones.

Benefits of air-cooled systems:

  • Less preventive maintenance
  • No water quality concerns
  • No need for an external chiller
  • Takes up less space and is easier to install
  • A cheaper cooling system in the long term
  • Has a smaller footprint

Furthermore, if you plan to install the CT scanner into a trailer or modular building, you should always choose a CT with an air cooling system due to the lack of space for water exchange.

Water cooled CT scanners

If your facility has a ready water source, such as a cooling tower or a factory chilled water system, then water cooling could be suitable.

You can also use a CT with water cooling if the facility does not have a sufficient water source, but then it will require an external chiller.

Benefits of water-cooled systems:

  • Almost zero noise
  • Clean – no dust from heavy airflow of fans
  • No additional HVAC system per room
  • Often cheaper aquisition cost
  • Suitable for rooms with inconsistent humidity and temperature control as temperature changes have less effect on the water cooled system than on an air cooled system

However, they take up more space, so you need to either have room for that, or to have the options of placing some of the parts outside and then run the cables through the wall.

Whether you decide to go for a water cooled or air-cooled system, make sure that the room environment meets the specifications listed in the CT scanner manual, including temperature and humidity.

CT Scanner Workstation

We are almost done, but there are a few more things to decide on.

One is whether to acquire a workstation.

A workstation is an option for most medical imaging equipment.

Since it is independent of the main modality console, you can process and analyze images while still allowing patients to keep coming in for examinations.
Furthermore, it enables doctors to analyze the images long after they have been taken.

If you plan to perform image analysis yourself, getting a workstation is necessary.

On the other hand, if you plan to send the images in a DICOM file to a PAC system located in a specialized clinic, focused on diagnosing and interpreting medical images, you do not need a workstation.

Difference Between Used, Refurbished, and New

When we talk about used, refurbished, and new CT scanners we refer to the condition of the CT.

So how do you choose between these three categories?

Used CT scanners

Used is used. Meaning that it has been used in another clinical setting.

The condition of used depends on the number of patients, how well it has been taken care of, but also of the supplier your purchase it from. Different resellers have different standards for what they do with the system.
LBN Medical for instance, test and check all incoming systems before they are put op for sale.

When buying used, the price is lower up-fron than for new and for refurbished. And if you buy a quality system, you will get good value for money.

Refurbished CT scanners

Refurbished can either be seller refurbished, ISO refurbished, or OEM refurbished.

Seller refurbished is defined by the seller from system to system, usually on request on the buyer. It can be comsetic or technical refurbishment.

ISO refurbished is a more defined process, and OEM refurbished is the OEMs performing a very specific refurbishment process on selected systems.

And of course with refurbished equipment, you pay for that extra effort. However, the price is still very attractive compared to new equipment.

New is simply brand new, from factory. Which you can buy from the OEMs.

Sum Up

Thanks for reading this far. In this paragraph, we will sum up the most important points from this guide to CT scanners.

  • What CT brand will be the best for my practice?

    You have many different options, although we recommend one of the following: GE, Siemens, Philips or Canon Medical. These brands have a long history of manufacturing CT scanners and are known for providing high quality.

    Choosing between these brands are mainly a question of access to service providers and your personal preference.

  • What type of studies will I perform?

  • What slice count do I need?

  • What type of CT scanner cooling should I get?

  • How much does a CT scanner cost?

  • How to measure CT scanner tube count?

  • Do I need a workstation for my CT scanner?

Thanks for reading this far

We sincerely hope you got valuable insights on CT scanners.

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