Radiography Equipment (For Non-Rads)

I was chatting to a friend recently and realised that I was talking gibberish with terms like CR and DR, so for non rads, I’d just like to briefly describe some current equipment in terms that should make sense; in conventional projectional radiography (eg not CT, MRI, ultrasound) there are three main types of kit, and as pretty much everyone has a camera now, that’s what I’ll compare it to.



Now I’m quite lucky as I’ve never had to develop a film radiograph; if I’d done A-levels and gone to uni straight afterwards that’d probably be different. This is a fairly easy comparison to make to photography as both have used film for the majority of their lifespans. You have an x-ray tube, a film plate, and the patient in the middle. The exposure would be made, and then the film would be developed while the patient waits.


Computed Radiography

Here, the plate is replaced by a digital cassette which is processed by a machine rather than dunked in noxious fluids. Cassettes are about a centimetre thick and come in a variety of sizes depending on what anatomy you’re examining. Cassettes are passive technology, and as such, if they’re dropped you won’t necessarily lose your data. Think of them as the old digital cameras which stored photos onto a floppy, but didn’t have a screen; you don’t have to wait to get the pictures back from Snappy Snaps, but you do have to take the disk out and put it in your PC before you can see if your thumb is obscuring that gorgeous sunset.


Direct Radiography

Same tube, same patient, but a digital receptor rather than a plate or cassette. These can be super-fancy; they’re usually connected to the radiography system wirelessly, meaning that as soon as you take the exposure the image appears on the screen in front of you. Unlike plates and cassettes, you can repeat images using the same receptor as it doesn’t store the data after it transmits it. Unfortunately, as it uses active technology, it’s not as small or light as a cassette and if you drop the receptor you’re dropping few thousand pounds’ worth of not terribly robust equipment. Not a good way to impress your manager. This is sort of like a modern digital camera with a screen and wifi connectivity.


This won’t pass any radiographical equipment essay marking criteria, but hopefully it will clear up a few of the terms I’ll be using in future blog posts.

2 Comments on Radiography Equipment (For Non-Rads)

  1. Jason
    August, 28th 2013 at 3:08 pm

    Nice post. First I’ve seen that actually digs into the equipment used in the industry. Have to also say that I love your pictures. Hope you’re still getting to travel.

  2. Ambrose
    September, 23rd 2013 at 11:24 am

    One word for your post: informative.

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