Quote:
Originally Posted by mugaliens
Nearly all x-rays taken these days are digital, for a number of reasons, the principle one being the fact they're far less expensive, per x-ray, than film. The second one is that they're loaded into the hospital's patient administration system, which allows any doctor seeing the patient to view the x-ray.
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Technically, there are two common modern ways to get those images in the computer, and only one is "digital", meaning captured originally by a digital sensor. The other option is to use a "CR" plate about the same size, shape, and weight as a film casette, which records an analog image, and then plug it in to a reader which pulls out the part that has the latent image recorded on it, scans it, digitizes its information, clears it, and slides it back into the cassette to be reused. "CR" came along before true digital sensors did and was named, as an alternative to film radiography, "computer/computed/computerized radiography".
As a radiography student, I've worked with both, and even handled some film. Overall, I prefer CR. It's not as fast, but the difference between a few seconds and maybe 20 seconds is small, and the separate, independent sensor cassette allows more options and freedom for positioning. (And positioning to get the image at just the angle you need is a very big deal!) Also, digital sensors not only are fixed to the machine but also have a built-in "bucky", which slightly increases the distance between the anatomy of interest and the sensor and filters out some of the radiation. Sometimes you want or need that, but sometimes you don't really want it, and using CR cassettes gives you the choice.
For those reasons, even in the true digital radiography rooms with the built-in digital sensors, we still bring in CR plates for some exams. Also, even if the entire X-ray department were to use nothing but digital rooms, the hospital would still need CR readers and cassettes because they're the only way to get an image from the "portable" machines, the ones that get taken in to patients' rooms or out to their homes, because you physically can't build in a digital sensor for those. As a result, even hospitals and clinics that never touch film at all and are fully computerized have either all CR, or at most a mix of CR and digital.
(The thing about dentists doing it either way intrigued me; I'd never heard of digital sensors that small, but I've also never seen a CR image receptor that small either.)