Articles Summary

Posted  March 6th,  2019

Computed Radiography (CR) or Digital Radiography (DR)?


Whether you are just starting radiography service and need to cut down cost or upgrading your system to catch up with recent technology advantages, this question might pop up into your mind.

To Summarize the major differences between CR and DR systems, we will mention the most thought of aspects for any business.

  • Cost

Normally the first thing that comes on mind is, what is the cost associated of owning a CR or DR acquisition system and if the difference out weights the benefits.

Although CR systems still have cost advantage, the reduction in DR cost in the recent years, along with the continuous development of its technology, made it the preferred choice in most cases.


  • Dose Efficiency and Image quality

DR acquisition systems can produce same CR results at less x-ray dosage depending on the type of the flat panel detector (FPD) used. Whether the detector is CSI or GOS, it has two to three times more dose efficiency than CR system.

Less x-ray dosage is not only useful for patients but also for x-ray tube usage and consumption. It can prolong the x-ray machine life-time and make it more efficient in scanning dense tissues or obese patients.


  • Workflow and productivity

The DR acquisition and image processing takes a few seconds as the receptor (detector) is itself the image processor, it is a one step process. On the contrary the CR takes much more time from exposure to cassette scanning to image processing.

The speed of operation is crucial for practices with busy workflow and for small practices that are keen to offer optimum service by spending more time with patients.


  • After sales service support

There are pros and cons owning both solutions when it comes to after sales service.

CR systems have more mechanical parts and require more regular service than DR acquisition systems. On the other hand, CR cassettes are less expensive and not as risky to handle FPD.

Although FPD are getting lighter, more shock tolerant and less likely to get damaged, they still need to be handled with carefulness as they are more likely to get entirely replaced if damaged.

There are protective covers that limit drop accidents, they cost from $500-$1000. Some practices prefer to add drop insurance coverage for extra protection and for peace of mind.


  • Depreciation Value

If you are looking at the total cost of ownership not just the initial cost of owning a CR or DR system, then you need to factor in the depreciation value.

Thanks to the increasing number of FPD manufacturers, the competition is getting fierce and the prices are getting more affordable to consumers. Also putting more pressure on CR manufacturers to switch to FPD.

Moreover, the nature of FPD of being just a solid plate of pure electronics compared to the CR and its mechanical parts that age over time, makes the FPD more reliable asset that can keep its value for a longer time.

Read more

Posted  January 5th, 2019

What to consider when buying an x-ray machine?


When time comes for purchasing an x-ray machine, many buyers with no related technical knowledge will get confused between different machines’ specification, and consequently might not be able to compare prices fairly.

To start, let’s all agree that an x-ray machine consists of two basic parts, the x-ray system for x-ray radiation and the acquisition system for receiving and reconstructing an image. Calling the machine conventional or digital in todays’ market depends on whether the two parts are integrated or not.

  • Digital x-ray machine = x-ray system + digital acquisition system
  • Conventional x-ray machine = x-ray system or x-ray system + conventional screen film (SFR)

Here is a very basic explanation of the x-ray system and what features to consider when buying and x-ray machine.

       I.  X-ray System

The main component for an x-ray machine is the tube and how it is mounted (floor mounted, ceiling suspended or portable unit), everything else could be optional. We will start with the patient table and the common features you might need to think about.

  1-      Patient table (PT)

If you are a chiropractor, you wouldn’t need a patient table. If the machine is for a hospital or imaging centre, then PT would be a necessary part and you’ll need to decide which table is more suitable for your business.

  • 2-way floating table: It moves in two directions, can be considered if you are a vet clinic.
  • 4-way floating table: It moves in four directions, and this is the common type for most diagnostic imaging practices
  • Fixed or elevating table: Fixed is more convenient for limited budgets as you might need to invest 4k-8K more for motorised elevating tables.
  • Automatic Exposure Control: AEC function controls and limits the amount of x-ray exposed to patients making operators’ exposure-errors less likely to happen.
  • Rotating bucky: It makes it easier to rotate the cassette or detector without taking it out of the tray. It saves time and makes the operators more satisfied, but not a necessary feature.

2-      Wall Bucky Stand (WBS)

Wall bucky stand can be very basic or very advanced. Below are optional features to consider.

  • Automatic Exposure Control: AEC function as mentioned in the patient table
  • Fixed grid: Wall bucky stand usually comes with moving grid but can always be replaced with fixed grid. (The fixed grid doesn’t make noise as it doesn’t need to move during x-ray, better in removing scattered radiation also more durable as no communication needed between grid and x-ray during exposure but it is more expensive option)
  • Motorized movement: Most of the wall bucky stands are counter balanced but there are optional features to have them motorised for even easier lifting
  • WBS tilting: Tilting the detector is always an optional feature making life easier for operators and patients, but all comes with additional cost
  • Remote control of the WBS movement: Mostly available in all brands and not offered unless asked for.
  • Synchronization between tube movement and WBS is a feature that limit the double work for operators as they don’t need to adjust the two parts. They just adjust the tube and the WBS will get aligned automatically. Very nice feature if you have a very big flow and you need to save time.

3-      X-Ray tube mounting designs 

There are mainly two options for tube/collimator mounting.

  • Floor mounted/floor-ceiling mounted (No big differences, only depending on the room dimensions and set-up)
  • Ceiling suspended: Provides more flexibility in tube handling and positioning. It is more convenient solution when scanning emergency or in-patients while they are on their transporting trolleys, without the need to carry them onto the patient table.

4-      Generator power rating:

There are different generator power specifications depending on manufacturers. Below ranges are just to give a closer idea.

  • 30KW – 50KW systems: Ideal for VETS and Chiropractors
  • 50KW- 80KW systems: More ideal for hospitals and medical imaging centres.
  • 3KW-20KW systems: Ideal for portable x-ray systems. From small animals to humans.


       II. Acquisition Systems

In todays’ market, an acquisition system can be either through cassette readers (CR) or flat panel detectors (FPD). We will tackle a few main points to compare between both solutions and the related cost, without going in deep technical details.

  • Speed: FPD takes 2-6 seconds to acquire and reconstruct an image. CR can take an average of a minute to get the one image processed depending on operators’ speed. The advantage of multiple scanning at the same time using detectors versus one by one using CR systems gives FPD superiority in speed.  


  • Panel handling: Although most of the recent FPD are shock tolerant, however, they should be always handled with care as there is a possibility of getting damaged if dropped from a distance. CR cassettes are much safer to use and less likely to get damaged.


  • Image quality against applied dosage: One more advantage of using FPD is the image quality specially if you are using CSI detectors which can give a better image quality at less applied dosage (which is also good for prolonging the life time of your x-ray machine).


  • Panel Size: FPD comes in one size of your choice, the most common is the wireless 14’X17” but there are options of tethered or wired 12x 12 inch or 14 x 17 inch or 17 x 17 inch. For the CR you can easily have the 3 sizes available with every CR system.


  • Cost of ownership: When it comes to cost, CR systems win for the short-term, they can be a better choice for a new starting business or a business that has limited number of patients every day. However, considering depreciation value, satisfaction of stuff, speed and quality of work, FPD might be a better long-term investment choice even for small business.

Read more

Posted August 3rd, 2018

CSI or GOS Flat Panel Detecor?

Detector Plate

If you ever came across a situation to choose between CSI and GOS detector, what would you choose? 

Based on a common question that we are always asked; “which detector is more convenient for my practice, the GOS or the CSI detector"

There are two main materials being used as scintillators in the manufacture of these detector panels: gadolinium oxysulfide (GOS) and caesium iodide scinitilators (CSI).

CSI detectors have the advantage of higher resolution and less x-ray dosageapplied to the patients. You can apply around 10% less dose using the CSI detector and get same results using GOS detector. On the other hand the CSI detectors are roughly 20-25% more expensive.

A) X-Ray Dosage:

Does 10% sound like a big number? We can do a quick mathematical equation to understand the effect.

We can say the average common spine exposure is about 1 mSv in dosage. It varies depending on the machine, FOV, patient…. etc.

So, doing the calculations, the 10% more dosage using GOS detector for a single spine x-ray is equivalent to 0.1 mSv.

Sounds Good! But what is the annual limit for radiation exposures? 

Based on the Australian Government’s primary authority on radiation protection and nuclear safety, the current limit of radiation exposure for an individual is 20 millisieverts (mSv) per year averaged over 5 years, and not more than 50 mSv received in any one year.

  • 20mSv ≈ 20 spine x-ray exposures using CSI FPD ≈ 18 spine exposures using GOS FPD.

Although we do not have clear numbers about the average dose from CR systems to achieve same GOS results as there are so many factors included but it is on average of 5%  ̴  15% higher.

(20 mSv ≈ 8 CT Head examinations ≈ 3 CT head+abdomen+pelvis examination ≈ 1 PET CT examination).

So, the extra x-ray dosage from the GOS detector for spine x-rays will not be the huge contributor for the patients to reach their annual exposure limit.

Although we proved the differences are minor, we should always strive to make exposures as low as possible following the “As Low As Reasonable Achievable” principle (ALARA).

B) Resolution:

However, the resolution of the CSI detector is slightly better, it is still an advantage that cannot be ignored, even if it can contribute to one more pathological finding for every hundreds or thousands of cases.

Obviously, the CSI detector is a better choice, but because of the budget constraints, whether you are introducing a new digital imaging service or upgrading from a Cassette Reader (CR), this is one step forward towards a better service to the patients and to the community.

Read more