Frequently Asked Questions NDT

Non Destructive Testing

1. What is Amorphous Silicon (a-Si) Flat Panel Digital Radiography (DR) technology?
2. How is the a-Si digital radiography inspection system deployed?
3. What are the benefits of using a-Si digital flat panel detectors in comparison to traditional film?
4. What is the image quality and sensitivity of a-Si flat panel radiography compared to traditional film?
5. What are the different active area sizes of the available a-Si flat panel detectors?
6. Can the a-Si flat panel detector be provided with different types of fluoroscopic screens and what is the effect?
7. If I already have a Vidisco CCD based imager, can the Vidisco flat panel system still operate it?
8. Are the Vidisco Flat foX-17 & foX-Rayzor suitable for field battery operation?
9. Can the Vidisco Flat foX-17 & foX-Rayzor be used for stationary NDT work?
10. What are the typical industries that benefit most from using the Flat foX-17 & foX-Rayzor for field NDT Work?
11. What are some of the industries that use DR a-Si flat panels in stationary fashion?
12. What is the image quality advantage of the a-Si flat panel Flat foX-17 & foX-Rayzor field operated systems compared to CCD based systems (i.e. foXrayII/RTR/DRS-2)?
13. Which X-ray sources can be used with the Flat foX-17 & foX-Rayzor?
14. Cay an existing customer X-ray source be used?
15. What is the average size of a regular X-ray image file? And is it not too big to process on a laptop?
16. I have an existing stationary a-Si flat panel detector. Can you use my flat panel and make it into a portable system?
17. What is CR technology?
18. What is DR technology?
19. Does Digital Radioscopy (DR) eliminate a workflow step in the processing of X-ray images in comparison to other radioscopy technologies (film, CR Phosphor plates)?
20. How does the CR system acquire an image?
21. Is Amorphous Silicon DR Digital Radiography more portable than CR?

Q:

What is Amorphous Silicon (a-Si) Flat Panel Digital Radiography (DR) technology?

A:

It is based on a digital flat panel detector, which unlike traditional film or Phosphor plate replacements, can provide instantaneous digital readout of an X-ray image providing the operator with "real time" images, or what we call "image upon request". The operator does not have to change film or Phosphor plates in between shots, and no development or scanning time is required. The image is available a couple of seconds after the X-ray is fired and it immediately appears on the computer monitor providing instantaneous results.

The panels are produced with a gadolinium oxysulfide scintillator which is quite rugged to the elements and environmental conditions thus lending itself much more readily for portable applications mounted on an amorphous Silicon plate. The scintallator emits light photons in direct proportion to the energy of the X-ray striking it. The photons are picked up by the underlying array of amorphous Silicon photodiode matrix, which converts them into an electric charge (electrons). This charge is then converted to digital values (signals) for each individual pixel. Amorphous Silicon Flat Panels were initially introduced for medical applications as high quality replacements for traditional film being used in the early 1990’s.

For more information see our Amorphous Silicon info page.

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Q:

How is the a-Si Digital Radiography inspection system deployed?

A:

Deployed foX-Rayzor System

Just as with any conventional X-ray, the inspected item is placed between the X-ray source and the imager, which in this case is an a-Si digital flat panel detector. The X-ray source is fired, energizing the digital flat panel detector. Once the image is captured and read out, it is immediately displayed on the computer monitor, and ready for a wide range of image enhancements, extreme zooms (up to 800 percent) and Window Leveling, to make full use of the wide dynamic range presented by this technology.

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Q:

What are the benefits of using a-Si digital flat panel detectors in comparison to traditional film?

A:

The main advantages of a-Si Digital Radiography (DR) flat panel technology over traditional film are:

1. Fast set-up & immediate results.
2. Sensitivity: DR can acquire the image in as little as few milliseconds, while film can take several minutes per image. Depending on the type of film being used a-Si DR can be 10-100 times more responsive.
3. No repositioning of film cassettes/no returns to the area of interest for re-shoots.
   Typical NDT Equipment CCD-Based foXrayII Portable X-ray Inspection System
4. No purchasing, storing and disposal of consumables - DR users can benefit from up to 97% reduction in equipment footprint.
5. No processing of film required including the handling chemicals or equipment maintenance, meaning that a-Si is environmentally friendly.
6. "Cost free" imaging, infinite "reshoots". Once the initial purchase has been made, there are no additional costs per X-ray image.
7. Images are immediately captured and stored in digital format, which enables exact reproductions, easy storage and easy exchange of image information between users.
8. Easy, on the spot measurement and annotation of indications or defects.
9. Compact, inexpensive and permanent archiving with multiple backup possibilities.

10. When switching from film to DR, users working extensively with X-ray can recover their investment on equipment within four or five months, with a savings or over $6,000 per month per system:

    Traditional Film Radiography
    Equipment (initial one-time cost)		Recurring Costs (per 1000 exposures)
    Film processor	$28,000	Film Chemicals Waste disposal Processor Maintenance Other consumables
    Film feeder	$8,700
    Dark room	$20,000
    Tank set	$280
    Silver recovery unit	$2,000
    Pump station	$900
    Twin illuminator	$640
    Film filing cabinet	$900
    Total	$61,420	$6,000 (per month)
    Amorphous Silicon DR - Digital Radiography
    Equipment (initial one-time cost)		Recurring Costs (per 1000 exposures)
    Total	Similar to traditional film cost above	1 CD-R disk: 24 cents

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Q:

What is the image quality and sensitivity of a-Si flat panel radiography compared to traditional film?

A:

A-Si flat panels detectors can be more sensitive than traditional X-ray film by a factor of 10 to 100 times, therefore dramatically requiring much less exposure time when taking an image with a-Si flat panel detector! For example: when using a commercial pulsed 150kV or 270kV source, an entire image can be achieved with only one pulse, which is the equivalent to 60 nanoseconds width of exposure (a minimal amount of energy!). The detector acquisition read time and presentation of the entire image on a laptop screen will take approx. 2-5 seconds, depending on the size of detector used.

Regarding dynamic range, film is quite limited to several hundred gray levels, however, bear in mind that since the human eye can see only somewhere between 60-100 gray levels, the relative sparse dynamic range of film can not be fully utilized or visualized with any ease. In comparison the a-Si flat panels detectors have a very wide dynamic range of 14 Bits or 16,384 gray levels. By using the automatic or manual "Window Leveling" feature built into the Vidisco software, the operator can utilize the computer to scroll through the entire gray scale range showing us "gray scale slices" of that range that our human eyes can distinguish. In other words, the computer allows the operator to practically benefit from this vast dynamic range in way that would never be possible with film.

20 Line Pair / mm 20 Line Pair / mm - magnified

Depending on the type of scintillator used, a-Si flat panels detectors can provide resolution of up to 4 line pair/mm when items are positioned directly adjacent to the panel, however when using a good micro or mini-focus X-ray source and geometric magnification (moving the target closer to the X-ray source, away from the imager, the resolution can be improved up to tens of line pair/mm).

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Q:

What are the different active area sizes of the available a-Si flat panel detectors?

A:

Flat foX-17 system includes a detector with an active area of 28.4 x 40.6 cm (~12"x16" inch). 

foX-Rayzor System includes a detector with active area of 22.3 x 21.6 cm (~9"x8.5" inch).

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Q:

Can the a-Si flat panel detector be provided with different types of fluoroscopic screens and what is the effect?

A:

Yes, any a-Si flat panel detector can be offered with one of two types of fluoroscopic screens, either a Fine screen or a Fast screen. The Fine screen type stresses the fine sharp images with up to 4 line/per mm and is best for use with easier to penetrate items. The Fast screen type is a more sensitive screen that provides approx. 6-7 times more light at the price of gaining some unsharpness, albeit small. This screen would be the choice for difficult to penetrate items like thick concrete, steel, etc. and is used in most applications.

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Q:

If I already have a Vidisco CCD based imager, can the Vidisco flat panel system still operate it?

A:

Yes. Vidisco has a retro operation kit which allows any of our a-Si flat panel systems to be able to operate older CCD based imagers.

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Q:

Are the Vidisco Flat foX-17 & foX-Rayzor suitable for field battery operation?

A:

Both systems are especially designed to perform on-site field work and are housed in one ruggedized hand-carry "Storm" case on wheels. The systems can be easily moved by one person and are fully battery operated, lightweight & small. The a-Si flat panels have easy to grip handles and are tripod mountable (using the Vidisco tripod mount option) and are laptop driven (No PCI Cards necessary). Each Vidisco system is provided with a 50m lightweight cable on reel connecting between the imager and the computer. This one cable handles all power and data requirements. Furthermore, Vidisco a-Si systems can also be operated fully wireless (either wireless X-ray and data operation or both are available).

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Q:

Can the Vidisco Flat foX-17 & foX-Rayzor be used for stationary NDT work?

A:

Yes, in addition to their uniqueness that enable a fully battery operation mode for field inspection, the user can benefit from using the a-Si flat panels in a stationary fixed fashion. DR a-Si flat panels are used in much the same way as film and can be left in place while robotic or conveyor belt systems bring parts to them or reposition parts from multiple views. The operator does not have to change film or plates between shots, and the X-ray image is available within seconds after firing the X-ray, greatly improving on the inspection productivity (compared to working with film). Flat foX-17 & foX-Rayzor are unique by providing both a portable field and stationary solution in one system.

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Q: 

What are the typical industries that benefit most from using the Flat foX-17 & foX-Rayzor for field NDT Work?

A:

Digital X-ray imaging for EOD/IED by Vidisco

Due to the numerous advantages digital radiography offers compared to film based X-ray, Vidisco portable digital X-ray inspection systems are used for many applications including homeland security.

Petro-Chemical Industry

For on-site inspection of plants and performing regular maintenance inspection of insulated pipes, joints, welds etc. without the need of dismantling pipe segments, removing insulation for leak tracing and halting production for long periods of time.

Aerospace Industry

For on-site inspection of aircraft in place of dismantling wings, rotors and other parts and taking them to an X-ray room for inspection. By using the a-Si flat panel detector on manned or unmanned aircraft (UAV’s) in the field or hanger, the NDT professional can verify components assembly and part fit-up, detect foreign objects, honeycomb defects and make quick decision regarding pipes, welding integrity and more.

Forensic

Murder/arson investigations with on-site X-rays without having to move the object from the scene enabling enhanced ballistic analysis, fire damage, etc. before any disintegration of the evidence occurs.

Veterinarians

For inspecting any animals on-site from race horses, to domestic, farm and zoo animals without the need to transport them to a clinic with a stationary X-ray room. The major benefit of using a portable battery operated a-Si flat panel detector is its extremely fast image acquisition, combined with the capability to be able to "bring the system to the target". In addition, due to its high level of sensitivity, the required exposure will most likely be shorter than what was previously required with film, with instantaneous results and no processing required. Should the subject need to be re-X-rayed, this can be done on the spot, and will be known immediately.

Security NDT

On-site inspection of ammunition in warehouses without the need to move the volatile live weapons. See Security FAQ for more information.

Q:

What are some of the industries that use DR a-Si flat panels in stationary fashion?

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A:

Aerospace industry: for aircraft parts in production or QA stage, welds, composite material, electronics components, casting parts etc.

Petro-Chemical Industry: for tubing welds, isolated pipes.

Automotive industry, casting. Agriculture products, and any industry that needs to replace film based X-ray with high productivity and return on investment can embrace the a-Si digital radiography technology.

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Q:

What is the image quality advantage of the a-Si flat panel Flat foX-17 & foX-Rayzor field operated systems compared to CCD based systems?

A:

The a-Si flat panel Ssstems reflect a quantum leap in the image resolution. We can see up to 4lp/mm with the digital panels, meaning that it offers about 10 times the resolution of CCD based systems that provide only up to 1.3 line pair/mm (the pixel size area for this unit is approximately 10 times smaller). As for the dynamic range, the digital panels provide 14 Bit data, meaning that they have 16,384 gray levels building the X-ray image, instead of the 8 Bit (256 gray levels) in a standard CCD based system - that represents 64 times greater dynamic range (i.e. 64 times more information delineation).

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Q:

Which X-ray sources can be used with the Flat foX-17 & foX-Rayzor?

A:

The systems can basically be used with any X-ray source up to 160kV, and higher with additional shielding. Of course, as these are truly portable and battery operated systems, the most commonly used X-ray sources are also battery operated providing a completely autonomous and fully portable solution. The line of Golden Engineering's pulsed X-ray sources (Golden XR150, XR200 & XRS-3) are ideal for usage with the Vidisco portable inspection systems. These portable X-ray sources can be packed right into the system carrying case. These sources range from 150 - 270kV and are quite powerful for their size.

In addition, we can offer a battery operated constant potential 120Kv (CP120B) or160Kv source for specialized applications.

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Q:

Can an existing customer X-ray source be used?

A:

Yes, both standard Flat foX-17 & foX-Rayzor can be integrated for use with customer’s existing X-ray sources. All that is required is to prepare an activation cable for the specific X-ray source to be used, and the Vidisco software will be able to control the firing of the X-ray.

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Q:

What is the average size of a regular X-ray image file? And is it not too big to process on a laptop?

A:

The X-ray image file size of an image acquired by a foX-Rayzor System with active area of 22.3 x 21.7 cm is approximately 5MB. The X-ray image file size of an image acquired by a Flat foX-17 with active area of 28.4 x 40.6 cm is approximately 15MB. The Vidisco proprietary software is specially designed to easily and quickly manage these files with 16 bit processing without any screen flickering or delays. Vidisco designed the communication protocols for extremely fast data transfer and our software algorithms allow for 800% non digitizing zoom, automatic Window Leveling and easy data base compilations.

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Q:

I have an existing stationary a-Si flat panel detector. Can you use my flat panel and make it into a portable system?

A:

Yes. Vidisco has worked with nearly all the major producers of amorphous Silicon and by using the Vidisco designed Interface Control Unit (ICU), which is an embedded hardware platform, we can most likely retrofit your flat panel detector allowing it to be fully operated on batteries, laptop driven, and to work with one lightweight data/power cable. In other words, no PCI frame grabber, no heavy power supply and limiting cable, and no thick data cable would be required to operate your existing panel. You will no longer be forced to use a desktop computer and short cables to work with your flat panel. Your system will now be able to be easily transported in a "Storm" case on wheels, and tripod mounts for certain large format (Varian, Dipx and Thales) panels are also available. Contact your local Vidisco representative for more information.

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Q:

What is CR Technology?

A:

CR technology is Computerized Radiography, generally meaning using a Phosphor plate which is scanned by a laser scanner after being exposed to X-ray. This technology is very similar to film in the sense that the images are not retrieved in "real time" and must be scanned (instead of developed in the case of film) in order to retreive the data.

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Q:

What is DR Technology?

A:

DR refers to two different acronyms and meanings: either Digital Radiography which is a general term for digital panel technologies (includes amorphous Silicon or Selenium panels), or Direct Radiography where the digital panel detector creates the signal without the use of a conversion screen.

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Q:

Does Digital Radiography (DR) eliminate a workflow step in the processing of X-ray images in comparison to other radiography technologies (Film, CR Phosphor plates)?

A:

Yes, traditional film needs processing time and CR Phosphor plates/film need reading (scanning) time. DR takes the processing, reading or scanning out of the equation by producing instant results at the point of inspection by acquiring an image per request in as little as 2-5 seconds.

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Q:

How does the CR system acquire an image?

A:

CR technology utilizes a storage Phosphor plate in a hard or soft cassette much like the film cassette. The Phosphor is placed in the plate which is then positioned like a film cassette would be placed and the exposure occurs. The plate is then removed manually and taken back to the darkroom and placed in a reader. The reader has a laser scanner that reads down the information from the storage phosphor plate and displays the information on a monitor. This is interpreted for the results. The biggest advantage this technology has over traditional film is that the storage Phosphors are reusable and the images are saved on a computer. The processing time is similar and there are still the same cumbersome and time consuming steps to follow as with X-ray film and cassette.

In contrast, with an amorphous Silicon DR flat panel detector, the X-ray image is acquired immediately on site, in as little as 2-5 seconds, and is immediately visible on the computer screen.

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Q:

Is Amorphous Silicon DR Digital Radiography more portable than CR?

A:

Yes, the Flat foX-17 and foX-Rayzor a-Si flat panel systems are truly 100% field portable. They are lightweight and small, can be hand carried by a single operator, housed in one "Storm" case (including pulsed battery operated X-ray source) and are fully battery operated (No external power required). Vidisco even offers a backpack version of its foX-Rayzor system. A standard laptop (ruggedized model options are also available) controls the Vidisco systems and wireless operation between the imager and computer can even be provided. In particular the foX-Rayzor panel is only 13mm wide - thinner than a film cassette and is the thinnest digital imager produced! This panel also has an imaging area which starts right down at the bottom and over to one side, making it truly unique and convenient for tight positioning in field applications where generally we have limited access. Vidisco a-Si panels are also the only panels in the world that can be operated in a wireless format (unlike any other competing technology).

In contrast CR scanners of phosphor plates require external power and are larger in overall size. CR is much more time consuming and does not give any real time information.

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