Flat panel detector definitions (Fill fraction, dels, pixels, matrix size, pitch)

[@AminSediqi-ze3ye]

Thank you so much for the video, It is very helpful for me to improve my occupational knowledge.

[@HowRadiologyWorks]

It's my pleasure. Pass it on

[@matth.4896]

I like having the math problems in the video. Love your videos!

[@HowRadiologyWorks]

Glad you like them! I think I will make more for an online course. The problems don’t do as well on KZbin

[@hariniseshadri915]

Hi! Thanks so much for the video. As the detector sampling frequency increases so does the spatial resolution and should be twice the signal frequency. But I had read that as the sampling frequency increases the sensitivity may drop . Could you please explain how that happens?

[@HowRadiologyWorks]

As the sampling frequency is increased the detector elements are getting smaller and there are some electronic components which can not shrink so the fill fraction goes down because the fraction of the detector element that is actively collecting x-rays goes down. Since the fill fraction is lower the detector is less efficient at measuring the x-ray and hence will have a lower sensitivity.

[@dankuselkus7241]

What IS sampling frequency? I know we calculate it based on the Pitch / DELs etc, but what is its significance/what does it represent? I must be missing something significant because I've looked everywhere and I can't figure out if it's anything other than pointless extra measurement somebody came up with; it feels like I'm being told "The Abracadabra Value of the FPD is equal to twice the pixel pitch". Okay, the abracadabra value is 1mm; why does it matter, what new information does this give us we didn't have before, and why do I care? Why did I make up the abracadabra value in the first place? I have the same questions for Sampling Frequency. It's 2mm^-1, why does that matter? What do I know now that I didn't know before? I know we say it's another way to determine DEL size, but so is the abracadabra value, so is the Sampling Frequency and the Abracadabra value equally useful? Can someone please unlock this for my brain to understand before I end up in a mental institution.

[@HowRadiologyWorks]

howradiologyworks.com/digital-x-ray-sampling/ check out our post with the sampling frequency. We like units of frequency as traditionally we measure resolution in frequency such as the MTF. You can think of sampling frequency of the detector as the best that you could do on the resolution of the system and there are geometric effects and the focal spot blurring

[@no-de3lg]

Can you explain the actual composition of detectors and its components and how they produce pictures

[@HowRadiologyWorks]

Sure I’ll put that one on the list

[@no-de3lg]

@@HowRadiologyWorks you are a decent man i hope u become rich and successful even more my heart with you for your dedication and beautiful channel I couldn’t find anywhere else

[@no-de3lg]

Thank you 🙏 so much

[@HowRadiologyWorks]

You’re welcome

[@no-de3lg]

Also is there a master in radiological technologist ?

[@HowRadiologyWorks]

Yes Peator www.mdanderson.org/education-training/degrees-programs/school-of-health-professions/academics/radiologic-sciences.html , is an example of one although most technologists do not have this degree and it is more for professional development.

[@no-de3lg]

Im having difficult time with radon transforms and back projection how the hell the computer knows the attenuation values of every 1mm inside that slice the detector receives all the sum of these attenuation values there’s no way it could figure out each pixel attenuation values individually I think I need to start mathematics and calculus understanding them conceptually to understand how they works i hate just to remember the laws but don’t understand what it actually means

[@HowRadiologyWorks]

Paetor - have you watched our video and seen our blog post on filtered backprojection?

[@HowRadiologyWorks]

howradiologyworks.com/filtered-backprojection-fbp-illustrated-guide-for-radiologic-technologists/

[@rubyamir5245]

Annoying music 😰😰😰😰😰😰😰😰

[@HowRadiologyWorks]

Thanks for your feedback, I’ve taken music out of recent videos