what is computed radiography?
Good morning all
Hope you had a fruitful study of the material
Hope you had a fruitful study of the material
Yesterday we saw the meaning of DR and types as indirect and direct
Indirect uses a photostimulable cassette while direct doesnt
Indirect has two different modes of image acquisition: Direct and indirect modes. The indirect modes uses scintillator to convert x-ray photons into light
Indirect uses a photostimulable cassette while direct doesnt
Indirect has two different modes of image acquisition: Direct and indirect modes. The indirect modes uses scintillator to convert x-ray photons into light
I believe there is no problems so far or if you have any challenges, do let me know before we continue, so that the class will give their contributions which will shade more lights into our studies
alright sir
I want to believe we all are in order so lets continue
let us shade more lights into CR/indirect D.R
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Computed radiography is a cassette based digital radiography means cassette is used to deliver the latent image in the digitaliser
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
Beautiful @ Blaise
The CR has components as ID terminal, digitizer, the review workstation and printer with or without PACS system
some have the ID terminal incoporated in the digitizer while others have it separately
some have the ID terminal incoporated in the digitizer while others have it separately
When a radiographer has exposed the imaging plate, he takes it to the processing room, the patient details are typed on the computer or inputed with a swipe card, then the cassettee is inserted in the ID terminal or inside the digitizer for those who do not have a separate unit.
This must be put in a proper orientation, then the processor recognizes the IP
when this is done the radiographer clicks ID on the computer to assign the patient information on the image
This must be put in a proper orientation, then the processor recognizes the IP
when this is done the radiographer clicks ID on the computer to assign the patient information on the image
If the system has a separate ID terminal then the IP will be taken and inserted into the digitizer for processing.
If there is incoporation with the digitizer then the processing continues asfter assigning the names.
If there is incoporation with the digitizer then the processing continues asfter assigning the names.
The image plate or detector is very sensitive and is housed within the cassette
Because of its sensitivity to radiation and heat many departments make it a duty to clean it daily before start of work by inserting it inside the digitizer to erease any background excitation
Because of its sensitivity to radiation and heat many departments make it a duty to clean it daily before start of work by inserting it inside the digitizer to erease any background excitation
From time to time the IP can be brought out and cleaned by the radiographer to minimize artefacts due to dust particles
The IP in the holder or cassette like conventional films or intensifying screens has layers. In IP there are 5 layers
These layers include:
Protective or anti abrasive layer
The phosphor layer which is the sensitive layer
The base or support layer
Aconductive layer that minimizes incidence of electrostatic charges
The light shield layer which reduces possibility of image degradation due to lights releasing trapped electron within the plate before it is processed
Protective or anti abrasive layer
The phosphor layer which is the sensitive layer
The base or support layer
Aconductive layer that minimizes incidence of electrostatic charges
The light shield layer which reduces possibility of image degradation due to lights releasing trapped electron within the plate before it is processed
These plates are made of barium fluorohalides and can have additives or activators like europium to improve efficiency
HOW IS LATENT IMAGE FORMED ON THE IP?
Remember in physics there is a valency band and a conduction band in an atom in so way we have the ground state and excited state too
Remember in physics there is a valency band and a conduction band in an atom in so way we have the ground state and excited state too
The semi conductor materials are also made to act as holes
The IP reacts like the intensifying screen in that it fluoresences
when x-ray falls on the radioluscent cassette, there is excitation of electron on the IP which could cause partly fluorescences (this causes losses)
The excitation will cause electrons to be trapped at a higher energy level differentially according to the amount of radiation absorbed
The excitation will cause electrons to be trapped at a higher energy level differentially according to the amount of radiation absorbed
so, is that partly fluorescence the source of increased patient dose?
@ Emmanuel NO, it is just the behaviour of the material and the manufacturer has corrected for those losses therby doesnt mean you have to ncrease exposure factors as a compensation, just as the various layers also tried to improve efficiency
well received sir
Okay @Emmanuel
The content of this change in energy levels is read by inserting the cassette inside the digitizer, after the ID. The digitizer opens the casstte to extract the IP or detector.
The extracted detector is now passed through a laser beam. when this beam passess through the IP it releases the excited electrons to the groung state, this process liberates a blue light like Film screen systems.
The lights are picked up by the PMTs which acts as photodiodes and also multiplies or intensifies the quantity and this mechanism would help to compensate for background degradations.
the PMT after the amplification converts the lights into electrical signals, the ADC (analogue to digital converter) will convert this x-ray raw data into a digital information and numbers assigned according to the gray scales using the processing algorithms.
The DAC (digital to analogue converter) converts the digital image into a visible image whic h is dispalyed on the screen
The extracted detector is now passed through a laser beam. when this beam passess through the IP it releases the excited electrons to the groung state, this process liberates a blue light like Film screen systems.
The lights are picked up by the PMTs which acts as photodiodes and also multiplies or intensifies the quantity and this mechanism would help to compensate for background degradations.
the PMT after the amplification converts the lights into electrical signals, the ADC (analogue to digital converter) will convert this x-ray raw data into a digital information and numbers assigned according to the gray scales using the processing algorithms.
The DAC (digital to analogue converter) converts the digital image into a visible image whic h is dispalyed on the screen
After this process, an intense white light in the digitizer shines on the IP to liberate any pending trapped electron which could cause ghosting artefacts in subsequent exposure.
After this the IP is returned into the digitizer and closed before it is released for further use
After this the IP is returned into the digitizer and closed before it is released for further use
This scanning occurs in raster pattern meaning from ome edge to the other
The density on the image is a function of amount of energy absorbed, the intensity of the laser beam and the number of pixels (picture elements) which is a function of the sampling frequency.
The density on the image is a function of amount of energy absorbed, the intensity of the laser beam and the number of pixels (picture elements) which is a function of the sampling frequency.
During inputing the ID the radiographer also idenifies the exam and projection
There is what is called Exposure data recognition, histogram and look up table.
These are like refernce values with which the CR compares its information to, to determine if it is within acceptable range.
Just as your teacher may want to compare your performance in a quiz to a standard range to determine if you did pass or fail and the degree
These are like refernce values with which the CR compares its information to, to determine if it is within acceptable range.
Just as your teacher may want to compare your performance in a quiz to a standard range to determine if you did pass or fail and the degree
I hope we are all togrther so far,
please let me have your comments from everyone in class for us to see if we can progress or not
please let me have your comments from everyone in class for us to see if we can progress or not
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
I am still here following sir
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
Good @ Blaise
Thank you
Thank you
latent image formed after the excitation of phosphor material hit by x-ray photon
Sure @ Emmanuel
okay
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Morning. This is clear sir
In reply to SURPRISE AIMEE MUHIRWA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
Thank you@ Surprise
so what does that pacs help?
@ Emmanuel PACS means picture archiving and communication system
It has a memory and a network. Memory to store an image and a network to send image to connected offices or persons.
It means you can finish the processing and like whatapp or email send the image to the reporting radiologist without you going out or sending the image and result to the referring doctor even before the patient gets back to the clinic.
Hope this is clear
It has a memory and a network. Memory to store an image and a network to send image to connected offices or persons.
It means you can finish the processing and like whatapp or email send the image to the reporting radiologist without you going out or sending the image and result to the referring doctor even before the patient gets back to the clinic.
Hope this is clear
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Is it the same as that used in CHUB ?
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
CHUB has a digitizer which doesnt have a different ID terminal. The digitizer also does the duty of assigning patient information if the command is given by the operator.
I am not sure if they have PACS but if they send information from the consol directly to reprting or sending physician then they are using PACS
I am not sure if they have PACS but if they send information from the consol directly to reprting or sending physician then they are using PACS
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Yeah they process the image using the digitizer they input the patient information in the computer and the image will go directly to the patient code( this code is given to every patient)
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
I have a question on the ID terminal what are their use
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
@ Blaise they are used to write or assign patient information and exam on the image.
Most CR has the ID as part of the digitizer but CHUK has one CR in the CT room which has a different ID terminal but the one in the x-ray room has it as part of the digitizer.
In conventional darkroom you identify film by actinic marker before processing or ordinary marker after processing, thats the role of the ID terminal to assign the image and exam
Most CR has the ID as part of the digitizer but CHUK has one CR in the CT room which has a different ID terminal but the one in the x-ray room has it as part of the digitizer.
In conventional darkroom you identify film by actinic marker before processing or ordinary marker after processing, thats the role of the ID terminal to assign the image and exam
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Well received
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
But sir, Does the CR work the same as indirect DR?
At Gisagara we've used CR with photostimulable phosphor plates and I've seen this PPP in indirect DR..
So do they relate or quite the same?
At Gisagara we've used CR with photostimulable phosphor plates and I've seen this PPP in indirect DR..
So do they relate or quite the same?
In reply to SURPRISE AIMEE MUHIRWA
Re: Everything about Digital Radiography
Computed Radiography is also known as Indirect DR or Cassette based DR
In reply to SURPRISE AIMEE MUHIRWA
Re: Everything about Digital Radiography
Computed Radiography is also known as Indirect DR or Cassette based DR
computed radiography is the conversion of latent image to visible image due to excitation of phosphor material without displaying final image to silver halide films but with computer assembled to digital processor
In screen- film radiography the radiographic intensifying screen is scintillator that emits light in response to x-ray interaction .in CR the response to an x-ray interaction is seen as trapped electrons in a higher energy metastable state
In reply to MARIE CLAIRE NIYONIZEYE
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
@ Marie Claire
This is scholarly
This is scholarly
@Emmanuel
Nice
Nice
Good @ Emmanuel
Let us remember that the IP unlike the conventional film has only one active side. This side must face the front of the cassette, if it is inserted wrongly inside the cassette a poor output will be the result because we are using the back
Also, assigning the body parts and projection, adult or paediatric helps the machine to consult the look up table (LUT), Exposure Data recognition (EDR) and the histogram to verify if the information being carried matches the limit of values in each.
This implies if the exam is Chest paediatric the machine has a range of values on it and samples the data in the IP with that of the standard values
However, with innovations and wide latitude of different exposures you can still assign a wrong matches ans still have optimal images, by this i mean you can do skull x-ray and during processing assign it hand and it doesnt affect your output because the information falls on permissible limit
This implies if the exam is Chest paediatric the machine has a range of values on it and samples the data in the IP with that of the standard values
However, with innovations and wide latitude of different exposures you can still assign a wrong matches ans still have optimal images, by this i mean you can do skull x-ray and during processing assign it hand and it doesnt affect your output because the information falls on permissible limit
Please can we continue
Go on break or meet another day?
Go on break or meet another day?
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
On this issue, many colleagues are complaining that they re not getting messages in this discussions i don't know if it is network problem but it is that reason why many are not participating
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
How is this active part recognised
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
@ Blaise The best thing is to be careful to insert it back how u removed it from the container, nevertheless though the IP appears white but the back can be abit dull
Please, can we go ahead or adjourn the class
Hope many people hasnt left the class or didnt come for studies
Hope many people hasnt left the class or didnt come for studies
Still following sir
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
On this issue, many colleagues are complaining that they re not getting messages in this discussions i don't know if it is network problem but it is that reason why many are not participating
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
@Blaise thanks for the feedback.
We keep encouraging them to participate but they can do the troubleshooting:
Do they have MB?
Does their phone have internet where they are?
If yes how strong and consistent so far?
were they able to access the platform?
This is pertinent because if others at different places were able to connect we can narrow down the problem and find out how to keep adjusting.
On this note we can stop presently to continue during our next schedule, hoping they would join us subsequently.
Please, visit the module under digital radiography for assignment there after which should be ready by wednesday next week. Thanks
We keep encouraging them to participate but they can do the troubleshooting:
Do they have MB?
Does their phone have internet where they are?
If yes how strong and consistent so far?
were they able to access the platform?
This is pertinent because if others at different places were able to connect we can narrow down the problem and find out how to keep adjusting.
On this note we can stop presently to continue during our next schedule, hoping they would join us subsequently.
Please, visit the module under digital radiography for assignment there after which should be ready by wednesday next week. Thanks
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Some may have MBs today but tomorrow they cannot get them so it is still a problem to be here all at the same time, the internet also is not strong everywhere we are at so to get these messages they sometimes be hard for us. Some also they reply but their replies does not appear in the discussion. on the assignment i was asking if it is at the end of the notes of digital radiography?
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
@Blaise, is okay, we can keep trying dear, all those challenges are well noted.
Hope your class has the time table already for your reference.
No digital radiography still continues, in our next class we will talk about image quality and see how far we can go.
Hope your class has the time table already for your reference.
No digital radiography still continues, in our next class we will talk about image quality and see how far we can go.
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Thanks for your time, we appreciate it
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
So they are not bought separately?
In reply to BLAISE HERTIER IRASUBIZA
Re: Everything about Digital Radiography
by Sunday Joshua Akochi -
@blaise yes
When you buy the cassttes it has the plates.
The manuafcturers are often wise too to keep their business going by not allowing the cassttes of another product or model to be used on another
When you buy the cassttes it has the plates.
The manuafcturers are often wise too to keep their business going by not allowing the cassttes of another product or model to be used on another
In reply to Sunday Joshua Akochi
Re: Everything about Digital Radiography
Well understood thank you
Computed radiography (CR) is the digital replacement of conventional X-ray film radiography and offers enormous advantages for inspection tasks – the use of consumables is virtually eliminated and the time to produce an image is drastically shortened. Imaging plates are reusable. No darkroom or chemicals needed