A Level - CT/CAT scan voxel explanation

[@no-de3lg]

I love your channel but do i need to have basic calculs mathematics concepts to understand this i super appreciate your video i got so happy to see it in my home screen I have so much joy to see finally someone talk about it

[@patricktan7120]

Ok. Not a single video or website tells me WHY we subtract the 21 from the reading, and WHY we divide by 3 in the final step

[@ogardner2531]

Thank you for the question. We divide by 3 because there are 3 further scans after the initial scan so it is effectively 3 x as "intense". You do not need to know this for Alevel but interesting nonetheless.

[@notyourbusiness8579]

Great explanation! I'm a medical student so a little bit ahead of A levels but still, it helped me a lot to understand the fundamentals of the ct. So thank you! However, I would recommend to cut out the parts where you took a step back and began to explain again. It is a little bit confusing to hear the same thing twice. I began to wonder whether my phone has problems playing the video :D

[@mridu5685]

thanks a ton!!

[@tajprabha7286]

Thank you sir this video was helpful to me

[@KULDEEPSINGH-li6gv]

Hi Gardner, this video is very helpful, could you please add reference of figure you used in earlier session.

[@abubakarmuhammadtsamiya5864]

this is very interested lecture,coz now i really understood what voxel elements and image reconstruction is,but sir what up picture elements (pixels)?

[@ogardner2531]

Thank you. Are you referring to pixels on the screen? These are just the smallest "squares" you can see if you zoomed in on the screen. Cameras often have a pixel rating which just tells you the smallest piece of an image possible

[@weihai1shen743]

hi, nice explanation, but one silly question is it definitely works well for 2 * 2 dimension, but what's about large dimensions, like 100 * 200

[@ogardner2531]

Hi. Thank you. It is the same process but just on a larger scale. Sorry, but the algorithm that does this is beyond my knowledge of this topic and the A level requirement.

[@no-de3lg]

What are. You studying I like your kawaii pfp

[@DrAmine-ip8jm]

Thank you very mutch please in 5:58 we arrived to know that a=5 and c=8 then we can deduce that b=6 and d=2 why shall we continue the process

[@TrungLe-em2rg]

how did you do it can you share with me , thank you

[@karthicksk1324]

Where is voxel I can be seen??

[@ravindranathhospital1362]

I don’t understand why we do this calculations if the answer is same as what we had in the beginning.

[@ogardner2531]

This is just an example. In real life, they would not know what the values are at the beginning and this process leads to them (well the computer) finding out the values. Hope that helps

[@ravindranathhospital1362]

@@ogardner2531. Oh. I understood. Thanks

[@jannatulferdous1503]

Is this included in the 2022 cie syllabus?

[@ogardner2531]

The new syllabus says: "understand that computed tomography (CT) scanning produces a 3D image of an internal structure by first combining multiple X-ray images taken in the same section from different angles to obtain a 2D image of the section, then repeating this process along an axis and combining 2D images of multiple sections". So no specific mention of voxels but worth having a rough idea.

[@jannatulferdous1503]

@@ogardner2531 thanks!