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Location: CR vs DR Image Quality
Discussion: CR vs. DR, or Grid vs. Non-Grid (and/or Technical Factors)?
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tnxrayman |
CR vs. DR, or Grid vs. Non-Grid (and/or Technical Factors)?
Apr 17 2012, 2:13 PM EDT
I would argue that most of the differences noted in these images are primarily due to the absence vs. presence of a Grid/Bucky (and to gross overexposure on the CXR?), rather than being due to any advantage of DR over CR, unless the former is a newer unit with improved detail, etc., compared to the latter. I would also note that CR might be less likely to have mattress/other artififacts--or foreign objects--present. Finally--although this is a minor point--I believe the correct spelling for the word used in the discussion of the CR CXR to indicate "non-moving" should be stationary, not stationery (the latter representing, for example, the paper upon which we might write letters).
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metal-fan-666 |
1. RE: CR vs. DR, or Grid vs. Non-Grid (and/or Technical Factors)?
May 12 2012, 6:23 PM EDT
The CR images in both cases are certainly less than optimal due to the lack of grid usage. For the AP shoulder, the dedegraded image may also be due to underexposure with a mottle appearance over inferior angle of scapula - although this may be due to compression from extracting the image from PACS and reposting online. Without knowing kV usage and post processing paramteres it is hard to judge, but the non use of a stationary grid is concerning. I have never used DR, but the DR images look similar to what you would see with a CR image (using a grid) that has recieved double the exposure it needed.As for the chest, I have no idea why anyone would do any adult chest (excluding very thin patients) without a grid. The CR image is horrible, primarily due to lack of grid usage. Comparing an AP erect non grid CXR with an erect PA bucky DR is in no way a fair comparison. An AP Erect CXR using CR With a grid and exposure factors of 110kV and 6-8mAs on this patient would have produced an image similar to the DR, especially if the patient/cassette was straight and some caudal angle was used (or a 45 degree sponge placed behind the patients neck. If most radiographers would choose to use non grid techniques for CXR's and shoulders on what appears to be an average sized male then there are serious issues in the field of radiography. The reasons given for the poor CR images sound more like laziness, as the DR images surely used a grid. Do you find this valuable? |
mrenfinger |
2. RE: CR vs. DR, or Grid vs. Non-Grid (and/or Technical Factors)?
May 26 2012, 11:30 AM EDT
I agree... grids should always be used for mobile chest radiography - even with CR and DR, and I have been saying so for quite a long time (http://bloggingradiography.blogspot.com/2008/01/to-grid-or-not-to-grid.html). There's just no substitute for image quality. One of the challenges we face in the U.S. is that some old-school techs have been using non-grid techniques at 75-90 kVp for their entire careers, and don't understand the digital image acquisition process... they are developing poor habits among new grads in the field, and chastise them for attempting exposures with grids after I ask them to try it during class. Hopefully people will spread the word!
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metal-fan-666 |
3. RE: CR vs. DR, or Grid vs. Non-Grid (and/or Technical Factors)?
Jun 7 2012, 1:26 AM EDT
| Post edited: Jun 7 2012, 1:39 AM EDT
Best way to change their habbit is to find a larger patient who has had repeat x-rays with and without grids, the images should speak for themselves. Then ask them which images they would prefer taken of them once they end up visiting the emergency department every couple of months. I'm sure their opinion will change.
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